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Discussion

xxx, 2024-03-13 00:52

This Is How Pornstar Kayleigh Will Look In 10 Years xxx

Cruz, 2024-03-13 00:52

This Is How Pornstar Kayleigh Will Look In 10 Years xxx

Sam H, 2023-03-18 17:59

Hello

I made the soft latching momentary switch toggle on/off circuit here http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/electronic-circuits/push-button-switch-turn-on/latching-toggle-power-switch

It worked fine when the momentary switch (I used SPST micro-switch) was located in close proximity to the board (i.e. short wire leads of approx 5cm) but when I used it in my real world application where the wire leads were each approx 1.5m long, momentary presses of the switch only caused the high-side MOSFET to switch on momentarily and did not latch on (I had a 3mm LED powered from the high-side switched power out so I could see visually). With further experimentation I found that in order for the circuit to latch on/off, the switch had to be momentarily closed for such a very brief whisker of time that the circuit was not practical or useable. It was a challenge to close the switch for such a very short period of time, fractions of a second.

Now, I'm not sure why this should be. Does anyone know of a tweak or a workaround in terms of component values etc which would resolve this situation? Or even an explanation of what is happening and why? I have used all the correct resistor and capacitor values in the original Mosaic schematic above and used a CD4011 DIP IC

Keep up the good work by the way, an excellent site and resource

Sam

minji.zhang, 2023-02-08 04:08

I have browsed "Slew-Rate Control Reduces EMI", first of all thank you for your work, it is very well written. But I found that the Eqn. 8 formula seems to be incorrect through the study of the attachment of Note 1. Please check and look forward to your reply.

Nigel Cleveland, 2022-10-12 16:11

Hi, Im trying to use your polyniomials to add mV to temperature conversion into a spreadsheet im using. I notice the low end of the ranges are showing large errors, probably due to them being below the range of the coefficients used - example, -265 on a type K when your coefficients only go as low as -250. Are there additional coefficients i can use to make the low end of the scale more accurate? Thanks

CNINE, 2022-08-21 09:06

hi my product component is fail in market after the using of 5-6 months

Michael, 2022-08-18 04:28

Hello, I have created a Proteus model implementing a Press-ON-Press-OFF push button according to the first schematics of these pages:

http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/electronic-circuits/push-button-switch-turn-on/microcontroller-latching-on-off

http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/raspberry-pi/on-off-power-controller

For testing purpose, the Microcontroller is replaced by the LED10 to show Power on/off and SW2 for the I/O pin to reproduce manually the I/O

What I expect:

.short button press of SW1: LED ON

.and another short button press of SW1 toggles it back OFF

What the simulation gives: see the picture at: https://ibb.co/w7B1XWg

.short button press of SW1: LED OFF. See the left picture on the above link. The Probe is at almost 0V

.and another short button press of SW1: LED OFF. See the right picture on the above link. The Probe is 0.0826V

Can you please help me to find where the schematics do not work? Thx

Regards, Michael

Georges Quénot, 2022-06-03 05:40

Greetings,

Thanks for sharing this. These questions are about the "Cell Constant of Parallel Wire Electrodes" article.

In his 1909 JSTOR paper (https://www.jstor.org/stable/pdf/984152.pdf), A. E. Kennelly proposes acosh(a/r)/pi = ln(a/r+sqrt(a²/r²-1))/pi for the cell constant while you propose ln(2a/r-1)/pi. Both are asymptotically the same for large values of a/r but the difference is significant for small ones, e.g., ~1.317 and ~1.099 respectively for a/r = 2. I am not expert enough and/or I do not have the time to investigate but probably one of you is doing some approximation at some point (or maybe you both do with different ones). Could you please have a look and tell me which formula is the most correct one?

Additionally, is there a way to get, even approximately, the current density profile across the yz plane as a function of y?

Andi, 2022-03-20 09:41

Dear all,

my RPi Zero2 restarts immediatly after he has poweroff himself by pull low the GPIO.

What can i do? Are there any hints?

THX

Best Andi

Marius John Knop, 2021-10-26 08:37

Hi Mosaic Team,

Im writing my master thesis at the University of Paderborn in Germany. I need to develop a Sensor Board which measures the conductivity and pH value at low cost. For now I cant find a solution to measure the conductivity with a 4 probe sensor named LFS1305 from IST Technology. I developed a first circuit, but my mearsurements dont really work. Is it possible to help. I can send more detailed, when i upload an appendix.

Kind Regards Marius John Knop

Tom Barwa, 2021-12-27 17:47

Hi! I accidentally came here looking for information on the construction of microprocessor circuits based on MC68HC11 and found an excellent description of the QED development board. Unfortunately, this description not contains, at least for me, very cautious information - I mean logic equations for the PAL U2 chip - is only given for U1. Without it, I am not able to reproduce the U2 system in reality. Please add a description of the logic table ( equations) needed to produce U2 JEDEC file.

T andreas, 2021-10-17 12:17

How were the coeffients in the RTD rational polynomial functions calculated? The included spreadsheet shows the error results but not the computation method for the presumably matrix based interpolation of the data. I tried using coeffients as is, but clearly they don’t come out right for my device, which is zero degrees C at 1000 ohms.

T andreas, 2021-10-17 12:17

How were the coeffients in the RTD rational polynomial functions calculated? The included spreadsheet shows the error results but not the computation method for the presumably matrix based interpolation of the data. I tried using coeffients as is, but clearly they don’t come out right for my device, which is zero degrees C at 1000 ohms.

Jacob Christ, 2021-09-08 19:45

A warning, the shutdown circuit for a Rasp Pi (3B) give here doesn't always work:

http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/raspberry-pi/on-off-power-controller

When an ethernet cable is plugged into the Pi and the Pi is running on a battery the Ethernet cable seems to inject energy into the circuit and the N-Ch gate bounces when GPIO goes high impedance (50K pull up) which causes it to turn back on and keep the Pi powered. Seems to work okay without Ethernet connected, the bounce is still there but the gate goes below zero and bounces up to less that 1V and thus the N-Channel does not turn back on.

Rashi, 2021-06-13 11:35

Hello, http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/electronic-circuits/program-regulator-voltage For the Dynamically programmable feedback for variable output voltages can you explain me the connections of VC and VR what are they exactly Thank you.

ALEJANDRO MEDINA, 2020-09-14 16:54

good day

Can you please explain to me how to find the coefficients c1, c2 … c7 for the rational polynomial function formula, used to determine the temperature with respect to the resistance of a pt100

Thank you

Randall Dwornik, 2020-04-03 09:39

We have multiple of your legacy handhelds P/N HH11-RT2 which all are showing a dark screen at power up. Jumper J3 is removed so it should be a bright backlite but we still get the dark screen, I do remember this happening several years ago but do not remember the solution, do you know what could be causing this?

Thank you Randall

C. Nelson, 2019-11-06 19:15

I've been looking for a 9S12 development/proto board that I can use with my assembly language programming. I already have an assembly IDE, chip programmer with BDM connection so I don't need Forth/higher level language/etc. Nor do I need any on chip operating system.

Question: If I perform a mass erase (all memory on the controller including RTOS etc.), then is the PDQ Board Lite still able to function? Function meaning I can load my own assembler program and all headers/ I/O pins, reset switches, power ports are still available to the 9S12 controller. I didn't see anything in the schematic to lead me to believe that any of the interfaces would be inactive without the RTOS. It appears that all headers, I/O pins connect directly to the controller without any RTOS or kernel.

Thank you.

Sean, 2019-11-02 22:10

Hi, thanks for this great resource! I'm curious though, regarding the BCM2835 Pi's (old Gen 1's of A/B/etc. and modern Zero's), Do they really have multiple impedance/current limit outputs configuration and input hysteresis configuration? I can't find any mention of either of those much less how to set them in the BCM2835's peripherals datasheet, https://www.raspberrypi.org/documentation/hardware/raspberrypi/bcm2835/BCM2835-ARM-Peripherals.pdf

And if they don't, is 8mA or 16mA the proper static limit?

Thanks for any assistance

  1. ~~~~

Christo Viljoen, 2019-07-04 01:48

Hi, I have two questions regarding the Latch and Toggle Power Circuits, specifically for the circuit schematic of a latching push button ON/OFF power switch using a MOSFET high side switch

1) In the diagram there is an "Auto-Off Auto-On" (Switch?) What is this component, could you direct me to a web site where it is described?

2) BAV99 Diodes have 3 connector legs, do you only use the first Diode or do you connect both inputs 1 and 3 together? Can another diode be used? if so what value?

http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/electronic-circuits/push-button-switch-turn-on/latching-toggle-power-switch#press-on-hold-off-latching-circuits

Thank you so much, this site is a treasure trove of information!

Kind regards,

Christo

Darren White, 2019-05-05 16:02

Hi,

First of all, thank you very much for your helpful "Push Button On-Off" circuit. I am currently using it with an Atmel uC that is controlling servo motors for pressing buttons on an external device.

Can this circuit be modified to remove the feature of switching the circuit off with a 3-second press? Thus, I only want my microcontroller to switch the circuit off when detecting a momentary input from the On/Off switch.

Your help will be much appreciated.

Thomas Johansen, 2019-03-28 08:02

Hi,

I have a question regarding Thermoocouple masurement.

We have made a T-type Thermocoupler sensor using the rational polynomial function approximation. And the question os about the area where the temperatur is 0 decrees.

The T sensor is in a calibrator at zero decrees. The sensor is started and there is an internal heating from the electronics that needs to be stable.

The measured temp starts a -0.2 and rises over time when the electronic is heating up.

If we draw the curve for that (X is the time, Y is the measured temp), the curve flatten out when it reach zero decree for a few seconds. Then it continue claiming again. It is the same for all sensors.

Any idea why it behaves like this?

Thomas

Raymond Nation, 2019-03-03 17:09

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EJones, 2018-12-29 19:50

Gee this stuff on drivers is great. I'm very glad I didn't want to give up looking for source and document schema thanks so much for your big time work. There is nothing like learning.

Mr.AtiX, 2018-11-04 04:08

Hello,

Actually i have a Lab PSU, from a PC-ATX the 12/5/3.3V ouputs and a additional input (for other transformer/PSU testings), wired out on front Bananajacks. Works fine.

Now i search a shematic or example to enhance the Lab PSU with latched toggle switches.

When possible, wish to become: - One output, allways starting with Auto OFF. - The 4 Voltage source inputs, selectable (OR-gates). - a normal OFF (like as master off). - a delayed ON (apply the source input).

I'm new in shematic design, unsure how to use one of the Latch and Toggle Power Circuits-examples. May is a other way as to simple multiplied 4x the 4011 NAND? Also to use 4x MOSFET or Relays (maybe SSR) for the switched final Output?

Please, can you help me or give a hint for similar solutions? Thanks

Jose vicente , 2018-11-02 04:44

Hello, I've just found your website and I find it very useful with a lot of information. I relly like the circuit schematics png figures you post. My question is what software or CAD application are you using to draw these circuits? I would like to use it for illustrations on reports. Thanks in advance. Jose Vicente

Philippe Gerard, 2018-11-01 12:44

Hello, i implemented the latching push button On/Off presented on your site:

i added three LED + a resistor of 200 Ohm between ground and switch power. I wired to have a auto-off mode when starting, First of all, often the mode is on when i plug the battery to that circuit, but after a while the LED switched on alone. It seems like the LED help a capacitor to charge and switch on the circuit. I am kind of lost, i would like to validate the circuit for a product i am designing where i need a reliable soft on/off button.

http://www.mosaic-industries.com/embedded-systems/_detail/microcontroller-projects/electronic-circuits/push-button-switch-turn-on/latching-high-side-toggle-switch-circuit-press-on-hold-off.png?id=microcontroller-projects:electronic-circuits:push-button-switch-turn-on:latching-toggle-power-switch

Thanks for your help

Jose vicente, 2018-11-02 05:20

Philippe,

I had same issue with a very similar circuit. This is a high impedance circuit very sensitive to noise and leaks. The pass transistor leaks very slowly biasing the bottom transistor until enough voltage to turn on the pass transistor. When the crcuit is OFF, you may try touching the gates or drains with your finger and it will turn on. Similar if you place a 1 meter cable to those points ( antenna). The way you can fix this is replacing the left 100K resistor with a 27K resistor and also placing a .1 uF capacitor from the drain of the bottom transistor to GND. The lower value resistor will allow for a higher voltage at the drain of the bottom transistor reinforcing the OFF state of the pass transistor. The capacitor will bypass any noise pickup to GND.

High humidity or moisture may be an issue , conformal coating or potting is recommended.

Philippe Gerard, 2018-11-02 07:43

Hi Jose thanks a lot for your help. I tried your solution, unfortunately it didnt work better. sorry. I also found out that the vendor made a mistake in my 10 uF smd (when i measured it was 7 uF… it just gave a little hope because the first time it took three minutes to switch on again alone). i really have the feeling that some capacitor is charging whatever i do and switch on this circuit. What is strange is the fact that when i plug the battery the circuit switch on while i wired to Off.

Jose vicente, 2018-11-03 07:01

No problem. That is weird, the 100k resistor between gate and drain of the pass transistor is the only thing that will help to cut it off. Try with 10k or less or whatever you can afford on consumption as that resistor is between vcc and gnd while the switch in on. It may be your pcb something is leaking or your environment is too noisy. This is a simple circuit, experiment wiring it in protoboard or "in the air" so you can test it isolated as well as whether your particular transistors are ok. You may also replace the bottom mosfet with an NPN BJT like 2n2222 or similar. Keep trying, the circuit works. Also try it powering with batteries to avoid noise that could come from your power supply. All the best.Bold Text

Philippe Gerard, 2018-11-05 11:10

JOse. thanks again for all these information. i will check all of that. this circuit looks so good, i really want to understand how to use it. I connected a DC-DC converter behind this ON/OFF button ( a 9V to 3V converter) and it solved the problem. I have no idea what is happening, probably some input protection that remove the leaking current that charges the capacitor of the on/off button circuit? even if i am very happy that this module solve my problem, i am not reassured by the fact i don't know what is really happening to solve the problem

Mebin P M, 2018-10-20 10:07

Hi all,

I made the Raspberry Pi ON/OFF Power Controller as shown in this link

http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/raspberry-pi/on-off-power-controller

I m succeed with turn and turn off the circuit, but after some time about 1 minute, the circuits turns ON automatically, remains in that ON state. I used the components which are exactly shown in this circuit provided.

I m using this circuit to turn On a battery with 8.4V.

Can any one please help me

Sanjay Gosain, 2018-09-26 23:16

Hi,

 we are looking to buy three LCVR Driver Wildcards.

Can you please provide quote for these. How do I order these? Please let us know.

Thanks,

SAnjay

Bindu, 2018-08-11 08:07

I am looking for gps navigation message subframe efficient code in c

Fred Stank, 2018-05-26 19:01

Hi guys,

I am looking to implement the soft switch circuit in my design, specifically the "clamped gate voltage" version; a bit more context: the switch will drive-high the enable pin of an inrush limiter ic; the only voltage source is the battery mains (48v); the enable pin is 100v tolerant.

My doubt: given the higher supply voltage (48v) are there any resistors/caps values that you would change? Regarding the mos pair I already found an higher voltage solution (SI4559ADY).

Thanks,

Fred

Niall, 2017-12-10 16:57

Hi folks,

For a home automation project I'm trying to develop, I was looking at your "Battery Operated Latching Power Switch" for inspiration. My requirement is pretty similar. The major difference is that instead as a momentary switch I must to use a toggle (SPDT) switch. [I'm retro fitting a lightswitch]

- Toggling the switch state (OFF→ ON or NO-OFF) should provide power to the MCU.

- MCU will then do its thing and power off the device.

- If possible the state of the switch would be available in GPIO (although this is not strictly required).

- Once the MCU is off, the system should draw as little current as practically possible.

Could you advise how I might adapt the "Battery Operated Latching Power Switch" circuit to accommodate the above requirements.

Thank-you in advance, Niall

Eric Billingsley, 2017-11-05 09:46

There is a great GPIO library in GO at https://godoc.org/periph.io/x/periph/conn/gpio that should be added to the C and Python set.

Stefan, 2017-09-29 17:08

Hello togehter,

i need to calculate the resistance between two parallel wires in water. Now i tryed to understand your calculation "Cell Constant of Parallel Wire Electrodes".

Unfortunately i dont get how to manage the electric field to eqn 4. You write in the denumerator (a^2+x^2). But i will get for the denumerator sqrt(a^2+x^2). Can you please describe how to get that solution.

Best Regards

Stefan

ravi, 2017-08-06 18:18

we are using conductivity tiamo 856 model but we mesuring only conductivity then using conductometer mesuring total dissolve solids is it possible or not then possible how

Willaim Bilgus, 2017-06-27 20:39

I built the RasPi shutdown Circuit and coded a shutdown program for it as well for the Raspi 3B https://easyeda.com/Bilgus/New_Project-4ce1316bb1f6402985f8d1c4f196448d

Ziad Ali, 2017-02-21 23:11

I am looking for an OEM solution to our Data Acquisition need or any recommendation that support our need. Please find below the description of Data Acquisition board that will fit our requirements. • 3 Inputs Analog signal(X,Y,Z): Single-Ended inputs sharing common ground, Dynamic Range ±5V programmable to ±1V. • 3 A/D Converter: 14-16 bits sampling rate ˃100KSPS programmable. • GPS: To provide Location and UTC for each A/D samples. • Formatting Interface: To combine GPS Info with decimal reading of the A/D Samples. • RAM: ˃ 1GBytes. • Remote Interface: Any standard interface to receive simple commands, return simple status and down load the RAM in low speed with simple text format. • CPU: To initialize the system and acts for these commands;  Program A/D Dynamic Range and Sampling rate.  Start Measuring  Stop Measuring  Down load RAM  Provide Status

curtis newton, 2017-01-20 02:06

Hello,

I have build a small board with this circuit and I cant seem to make it work (nothing tunrs on)

http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/raspberry-pi/on-off-power-controller

as I try to simulate it with different setup, it is always ON on startup or always OFF on startup no matter the position of the on/off switch

did anyone ever tried this circuit before ? is there an existing implementation of it or is it just pure theory ?

regards

Eric B, 2016-08-01 09:51

I am in need of something to control strobe of LED's. I'm looking to start at 50ms on and 150ms off. I need to control 200+ LED's at the same time. I also need it to run off 12v. I also need to control the on and off times independently. Is there anything out there that I might find off the shelf??

Jonathan, 2016-06-08 05:10

Hi,

Thanks for your circuits and tutorials. I am using the ON/OFF Switch for the Pi 3 and I have a problem with software shutdown. When I press the button, the pi turns back on after it was shutdown. When I press the button longer to force it OFF, it is working and the pi doesn't reboot.

Here is my python script :

import RPi.GPIO as gpio

def loop():

  raw_input()

def shutdown(pin):

   gpio.setup(7, gpio.OUT, initial=gpio.LOW)

gpio.setmode(gpio.BOARD)

gpio.setup(7, gpio.IN)

gpio.add_event_detect(7, gpio.FALLING, callback=shutdown, bouncetime=200)

loop()

Thanks for your help.

Kyle, 2016-05-05 08:10

hello..

i am interested in building a logic circuit to remote start my vehicle but i am not entirely clear with the terminology used describing such circuits. i am a novice with digital circuits, but have had my hands in basic 12v auto alarms, stereos, home audio etc..

i think one of the circuits described on the "latch and toggle circuit" page: (http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/electronic-circuits/push-button-switch-turn-on/latching-toggle-power-switch) would be ideal, but my input would be a momentary 12v pulse (i.e. parking light flash then horn chirp) instead of a switch

here it is in layman's terms: when the key fob lock button is pressed once, the parking lights flash for approx .5 sec when pressed repeatedly the horn will chirp. i would like for the light flash circuit to activate a "latching" relay that would send power to another 2 "latching" relays that would successively latch when the next 2 horn chirp pulses get sent. this in turn would kick the engine starter circuit on for 3 seconds with a timer, or when rpms reach 1000 with a counter.. whichever comes first. this in turn would deactivate the start pulse circuit and activate a 5 minute timer that would kill the engine and also a brake light circuit that would kill the engine if the brake pedal was pressed before the key was inserted and turned to "on"

i know they make add on systems, but i would like to do it myself to save some cash and have fun :)

thank you Kyle

Ahmad Hosseinlou, 2016-04-04 02:55

Hi.I can convert voltage to Temperature with simple form use of formula But I have a problem to convert temperature to voltage please suggest formula for solution this problem.thanks

Marielis Rodriguez , 2016-02-15 19:34

Hello I work converting automotive mcu's for importing purposes, and I'm having problems with 9s12… I'm trying to find guidance as to what products are best and how to use them, or how to use the products I already have to achieve the goal wich is to convert cars for example Dodge Ram 2007 from KM to MI

Celso Caldeira Sant'Anna Filho, 2016-01-21 23:53

Hi! In your page http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/raspberry-pi/on-off-power-controller There'a diagram to make a switch to Raspberry Pi, I am new to this, and don't understand the schematics, what is the diode used near the button? Do I have to connect the diode, the capacitor and the resistor all together in a single 'leg' of the push button? (I am using a 4 'legs' momentary push button). All 3 capacitor are ceramic? (0.1, 1 and 10uF) I don't have this dual mosfet, can I replace it for 2 tip 122 mosfets? Thanks for the help!

Randall Dwornik, 2016-01-11 14:02

In attempting to change out the battery B1 in your legacy handheld we are having difficulty separating the motherboard from the display board to access the backside of the board, is the header H6 soldered in place on the motherboard?

Jeff Burk, 2015-11-11 16:54

I would like to use the push button latch circuit in Fig 3, but I need it to power up in On condition so that it drives the load immediately. I saw this option in other variations, but I don't know how to do it for Fig 3. Any help is appreciated. Thank you.

K Bhat, 2015-09-10 02:44

Hallo Sir, My professor has given me a task to compare the performance of RTD and Thermocouple. What I did was a simple test by keeping both of them in hot water ranging temperature from 40 to 100 degrees. I get a Temperature curve for Thermocouple but for the RTD have a all resistance values. So I looked by the resistance v/s temperature chart for RTD and obtained the temperature values. Now how do i compare there is atemperature difference of +_0,4 degree of RTD from the Thermocuple. But how do I talk about their sensitivity.

Hoping for some answer from your end K Bhat

Jerome Thoma, 2015-06-14 11:27

In "Controlled Turn-ON and Shutdown of Microcontroller Products" you mention that the circuit works well for input voltages from 5-18V. Will applying 12V not cause problems when shut-down is controlled through a GPIO pin of an MCU (3.3V)? Do I need to add more circuitry to translate signals between the two levels for the control IO lines?

Andrew Robinson, 2015-05-13 02:09

Hi - great pages

I think I have found an error in the Thermistor/Measuring Temperature Equation. You note the 'beta' for the equation should be 393 - I think it should be 3930

Thanks for the resources

Peter Gray, 2015-04-28 04:14

Hi,

I have a question about your type K type calibration table for converting mV to °C. The last column voltage range says 33.275 to 69.553mV but the NIST maximum for type K is 54.886mV which is 1372°C. The Temperature Range below that says 800 to 1200°C. But 1200°C is only 48.838mV from the NIST type K table. It 'seems' to me the 69.553mV figure is wrong and the temperature range is wrong. All the other columns figures line up with the NIST tables, just not this one. Typo's maybe?

Mathieu, 2015-04-15 22:12

I used the Push On/Hold Off schematic with a high current device (1.5A - 9V). I've experienced some rebound (on-off-on-off) before it shut down completely. I don't have this problem when I shut down a lower powered device. Do you have any idea how to fix this ?

Thanks, Mathieu

Mark Wargo, 2015-03-06 23:55

The link to the "Controlled Turn-ON and Shutdown of Microcontroller Products" page appears to be corrupted ("Firefox has detected that the server is redirecting the request for this address in a way that will never complete"). I assume the content is just a generalized version of what appears on the "Raspberry Pi ON/OFF Power Controller" page, but would still like to see any and all possible guidance. Thanks!

Paul Clifford, 2015-04-03 21:18

Thanks Mark, we've fixed that redirect loop!

Douglas Luis, 2015-01-21 18:17

Does the Wildcard Carrier Module (WCB-5F5R) contribute to the Capacitive Load Factor Limit? If so, what is its Load Factor?

Paul Clifford, 2015-04-03 21:25

The Wildcard Carrier Board hosts Wildcards just as other controllers do, so it has similar limitations with respect to the number of Wildcards it can host. At your prompting I've clarified that the Wildcard Carrier Board mounted on a QED Board has the same drive capability as the PDQ Board or QCard Controller on the page: Wildcard Bus Loading Limits.

Thanks, – Paul

Jang.SJ, 2014-11-29 13:26

Hello, "Battery Operated Latching Power Switch" to questions in the circuit.

In Tina-Ti Software, I may "power sw on" the output voltage drops And "power switch off", if maintained for more than 3 seconds, the output voltage rises. In this case, Is it a matter of interpretation Tina-Ti Software? Or, Is it a matter of Tina-Ti Software settings?

Thank you.

Stephan, 2014-11-27 14:48

Hi Nick,

Thanks for the great example of the "Raspberry Pi ON/OFF Power Controller". I wondered if you have thought about controlling the AC/DC converter as well? It would be great to switch this converter off as well, so that you do not even have the standby losses… Is that possible??

Paul Clifford, 2015-04-03 21:19

It's certainly possible Stephan, but we haven't done it!

Peter Gray, 2014-11-14 01:12

Hi, I've been playing with your thermocouple polynomial equations and have hit an issue. It's probably me but thought I'd ask before I continue with the head banging.

I have re-created your equations in excel for mV to Temp conversion for types K, N & R with no problems. Nice work btw.

However with the inverse equations (Temp to mV) I'm getting big variations. As an example, for the type N with Tcj = 0 degC I get 0.039059469 = approx 1.5 degC. At Tcj = 25 deg C I get 0.527885738 = approx 20 deg C. At Tcj = 50 Deg C I get 1.073021567 = approx 40.5 deg C.

The K is good at 0 and 25 but at 50 is approx 46 deg C.

For Type R at 0 deg C I get -32.5 deg C! At 25 deg C I get 25 deg C. At 50 deg C I get approx 41 deg C.

It's me isn't it?

Peter Gray, 2014-11-14 21:47

Yes it was me. Had to add a few extra sets of () to get the order of operations right. :-D

Paul Clifford, 2014-11-26 17:14

So glad you found it Peter. Yeah, parentheses can make the difference!

Robert, 2014-10-20 04:01

Hi,

How to isolate (use optoisolator) the GPIO4 (PIN7) from the output of the IRF7319? (for security Raspberry PI).

Best Regards, Robert

Matt, 2014-10-15 08:51

Many thanks for publishing this helpful circuit and its variations.

Using the configuration shown in Fig.7, and with the auto-on option disabled (0.1uF cap wired to input rail), I'm experiencing a problem where the circuit switches on about 90% of the times when unswitched DC power is applied. The on/off button works fine apart from that.

Please can you advise me on why this might be happening, and what to look for? It's affecting a client's prototype design, where quite a few PCBs are impacted by this. They have clearly used the Fig.7 circuit. Replacing the IC results in identical behaviour.

Kind regards, Matt.

Konfu, 2014-08-27 05:57

Hi,

I find your "Battery Operated Latching Power Switch" very useful.

I now just wonder: is there a way to modify the circuit so that only a long press (maybe 2-3 seconds) of the button will switch the circuit on and another 2-3 seconds button-push will turn it off again? I need to prevent someone from accidentially switching on the circuit. ;-)

Any help would really be appreciated and I guess a valuable add-on to this circuit.

Nick Guerette, 2014-09-30 23:26

Hi Konfu,

It is difficult to introduce a delay in both turn-on and turn-off using the simple dual-MOSFET circuit you referred to. However, adapting one of the circuits based on logic gates under Latch and Toggle Power Circuits, it should be possible to create a delay in both turn-on and turn-off. Try the following circuit:

Circuit schematic of two NAND gates with positive feedback creates a delayed toggle latch.

This is a simple example, and has its limitations, particularly that if the user holds down the button too long, the circuit will switch states again after a shorter delay, possibly causing undesired behavior. However, it's a useful starting point. The circuit above lists surface-mount components, but if you wish to use through-hole components, you may select from the following based on your power supply voltage range:

Robert, 2014-08-17 07:03

I use code from Pi Supply (http://pastebin.com/dczbWQ0T), It's works, but I have problem with hardware shutdown Raspberry PI after software shutdown. I created code "gpio.setup(7, gpio.OUT, initial=gpio.LOW)"- responsible for hardware shutdown, but I don't know how to put into code from PI Supply and get sequence software shutdown > next hardware shutdown. Please help :)

Robert, 2014-08-17 15:55

Ok, I use this code from site http://www.raspberrypi.org/forums/viewtopic.php?f=45&t=61297&p=598990#p598990 Is it possible to set a time delay switch off hardware shutdown ?. I set runlevel 0 for halt, but it still too fast for shutdown system.

Nick Guerette, 2014-08-26 20:31

Dear Robert,

I am glad you solved the voltage drop problem. I've re-hosted your schematic here (click for full size). forum_2014-08-04t1331_pi_power_sch.jpg The easiest way to delay the hardware shutdown is to increase the size of the 10 μF timing capacitor. For instance, if you increase it to 100 μF, it will take about ten times longer for the power to turn off after the output pin has been set low. There are two side effects to this, however:

  • It will also take ten times as long to force power off by holding down the button.
  • After power is turned off, it will take a comparable amount of time until power may be reliably turned on again, due to the time it will take the larger capacitor to discharge. During this time, pressing the power button may turn the circuit on only briefly, possibly causing undesired behavior.
Robert, 2014-08-27 03:21

Thanks,

To safely software shutdown I used in code: call('umount /boot', shell=True), In next lines: gpio.setmode(gpio.BOARD)gpio.setup(7, gpio.OUT) gpio.output(7, gpio.LOW).

Best Regards, Robert

Robert, 2014-08-11 16:20

Problem with drop the voltage to 4,7V solved, I changed USB cable and GPIO4, I use /boot/cmdline.txt and add config parameter bcm2708.w1_gpio_pin=<GPIO_pin_number>, and release GPIO4 for smart power :)

Robert, 2014-08-04 09:31

I have a problem with your solution when I use it, I drop the voltage to 4,7V. When connecting directly from the DC adapter is OK (5V), maybe its problem becouse I used SMD adapter (SO8 to DIP8) with precision dip socket, below pictures designed PCB:

http://icebox.pl/wp-content/gallery/pi-power/DSCF6920.JPG http://icebox.pl/wp-content/gallery/pi-power/DSCF6910.JPG http://icebox.pl/wp-content/gallery/pi-power/DSCF6913.JPG http://icebox.pl/wp-content/gallery/pi-power/PI_power_PCB.jpg http://icebox.pl/wp-content/gallery/pi-power/PI_power_SCH.jpg

Is it possible use a different GPIO than GPIO4 ? Do you have some program to use software shutdown ?

Best Regards Robert

Seppo Nurmi, 2014-06-25 08:29

Hi!

I have High voltage push button toggle switch with inrush current limiter http://1drv.ms/1jhnRTg . Dual FET is AUIRF7343Q. N-mosfet feedback is wired from high voltage and zener diode (15V) limits the gate voltage. The problem is that it stays on as long as I press the ON button. What is the problem with it? What is the purpose of R8? Is it needed at all if I remove the inrush control from the circuit (D6, R7, C7)?

Nick Guerette, 2014-07-30 17:36

Dear Seppo,

I've re-hosted your schematic here (click for full size).

forum_2014-06-25t1229_pwr.png

I do not see any problem with it; it seems faithful to the example circuit using-high-side-mosfet-switches-at-higher-voltages, except for using another 15V zener diode to limit the voltage to the N-MOSFET gate instead of the regulator output, which I do not see a problem with. I suggest verifying the wiring; as the circuit is designed, if you hold down the power button, the circuit should turn on for a few seconds, then turn off and remain stable in that state until the button is released, at which point the 1 μF capacitor will discharge and it will be possible to turn it on again. If the power output is on only when the button is held down, this suggests a wiring problem somewhere; perhaps the gate and drain of the N-MOSFET are reversed, such that the button is directly controlling the P-MOSFET.

Seppo Nurmi, 2014-07-31 13:42

I'm using printed PCB With no errors on DRC. It works for a while with some modifications. R5 300k –> 100k, R7 100k –> 10k, remove D6 and C7. At the moment the circuit does not work with capacitive loads (forgot the diode next to the feedback resistor R4). Also there's issues with higher voltages. The circuit does not handle 28VDC input voltages. Probably my Design does not filter the voltage peaks well enough in load dump situations.

Robert, 2014-06-23 10:03

Of course for 10 uF use electrolytic capacitor ?

Best Regards Robert

Nick Guerette, 2014-06-23 13:55

Hi Robert: Regarding the Controlled Turn-ON and Shutdown of Microcontroller Products circuit, the 10 μF output filtering timing capacitor may be either ceramic or electrolytic. The other smaller capacitors must be non-polarized ceramic.

Ed Slate, 2014-06-16 09:05

Hi, do you have mechanical drawings for the PDQ board? I was able to locate them for the QCard, but not the PDQ board. Thanks!

Nick Guerette, 2014-06-19 23:37

Hi Ed,

There are basic mechanical drawings of the PDQ Board and Wildcard form factor hidden under the Accessories section:

Robert, 2014-06-16 02:46

Hi,

1. I would like to make a similar circuit, maybe you know a replacement for the IRF7319 (SMD - Surface Mounted Devices) version DIP (THT - Through-Hole Technology) ? 2. Testing the "switch ON" be done without a connected GPIO? (if set to auto-off). 3. Questions to parts - diode: 1N4001, 1uF capacitor: what type ?, 0.1uF capacitor: ceramic, 10uF capacitor: electrolytic 4. Do you have a PCB design?

I try to make a version THT, SMD is too difficult for me.

Best Regards Robert

Nick Guerette, 2014-06-19 23:32

Hi Robert,

The Controlled Turn-ON and Shutdown of Microcontroller Products circuit requires both an N-MOSFET and a P-MOSFET, both provided by the surface-mount IRF7319. It seems that multi-MOSFET chips are uncommon in through-hole packages, so you'll need to use two separate discrete components instead. Discrete through-hole MOSFETs are generally intended for high-current switching, so will be larger than necessary for this application. MOSFETs with otherwise similar characteristics you could use in a push-on hold-off circuit are:

Edited to add components with higher VGS

The circuit will work fine without using an I/O pin, but the microcontroller will have no way to detect that power is being shut off, or to shut itself off. 1N4001 or any other silicon diode will work fine. All capacitors used should be non-polarized ceramic -Edit: except for the 10 μF timing capacitor which may be electrolytic. If you are using through-hole components, I recommend using a simple prototyping "perf" board.

Robert, 2014-06-25 05:50

Hi,

LastLast, one question :), Is it possible use a different GPIO than GPIO4 ?

Best Regards Robert

Ed Slate, 2014-06-03 12:36

I'm a new user to Mosaic+ and Mosaic Terminal and seem to be getting frequent "blue screens of death" while downloading files to my PDQ board from an XP host. After getting a blue screen of death, I can reboot the host and successfully download the very same file to the target. Any suggestions?

Nick Guerette, 2014-06-03 16:58

Dear Ed,

I'm sorry to hear that you're seeing a BSOD! For technical support with our products, feel free to Contact Us directly. We've never seen a Windows crash during usage of Mosaic Terminal before, but there are several things that may be at fault. This may be a bug in Mosaic Terminal itself, but it's best to rule out other possible causes. The other software that is heavily exercised in downloading code to a controller is the serial port driver, and driver problems are more easily able to cause a Windows crash than application software as well.

If you are using the usb-to-rs-232-adapter sold by Mosaic, then follow the link above and then click the link for the FTDI driver update page, and try downloading the latest driver from FTDI. If you are using another USB to RS-232 adapter or a built-in serial port, try updating the driver from Windows Update as follows:

  1. Right-click on "My Computer" and select "Properties".
  2. On the "Hardware" tab, click on "Device Manager".
  3. Expand the entry for "Ports (COM and LPT)".
  4. Right-click on the COM port you are using with Mosaic Terminal and select "Update Driver…"

You may also check the website of the manufacturer of the adapter (or for a built-in serial port, your computer or motherboard manufacturer) for updated driver software that may contain a bug fix.

If that does not work, we will need to isolate the cause of the BSOD using information provided on screen or in the crash dump. The first place to start in investigating a BSOD after the fact is to look at the Windows Event Log:

  1. Open the Control Panel under Start→ Settings.
  2. Click on "Administrative Tools", and then "Event Viewer".
  3. In the navigation pane on the right, select "System".
  4. In the list of logs that appears, look for an error at the time of the BSOD. Double-click on that error and see if it provides information about the nature of the error or any files related to it.

When the BSOD happens, there is information on the screen about the error that may also be useful, but by default Windows XP restarts immediately, making it difficult to read or record that information. To prevent the automatic restart:

  1. Right-click on "My Computer" and select "Properties".
  2. In the "Advanced" tab, in the "Startup and Recovery" box, click the "Settings…" button.
  3. Under "System Failure", un-check the box labeled "Automatic Restart". The next time the BSOD happens, you'll have time to read and write down the information it provides, which will include an error code and may also reference files that may be related to the error.

The dialog box above is also where you can ensure that Windows will create a Kernel Dump or Complete Dump, usually at C:\Windows\MEMORY.DMP . As a last resort, if the problem cannot otherwise be isolated, we may be able to set up a way for you to transfer the memory dump file to us to analyze using the Windows debugger, WinDbg.

Jose Lindo, 2014-05-11 14:14

Our Mosaic Template for dokuwiki is the best i can see.

Is possible download this greater template

Thanks

Paul Clifford, 2014-05-14 18:47

Dear Jose,

Thank you. We are currently working on making a downloadable version of our dokuwiki template so that others can use it. We've got a few tasks to do: we made some changes to the kernel that we'll need to migrate to plugins instead, and we need to test it with the newest dokuwiki version. But we're eager to get the template into others hands so they can use it too.

HyunJoon Kang, 2018-12-05 11:14

Hello, I think this Mosaic template is the most outstanding one in numerous Doku wiki templates. Is the downloadable version of this template ready?

Ruedi Heimlicher, 2014-05-10 06:21

Hi I am experimenting with the ON/OFF-switch. It works as it should, with one exception: I have an EDIMAX WLAN-adapter that works great when the raspi is powered via the micro-USB, but not with tho ON/OFF-switch. I cannot ssh to the raspi. Adding a big capacitor - 1000uF - to the power-output after the MOSFET helps sometimes, but not always. Any ideas? Thanks Ruedi

Paul Clifford, 2014-05-14 18:52

Reudi,

My guess is that the power supply you are using can't sustain the current required by both the RPi and the WLAN adapter. That adding the capacitor sometimes helps indicates that it is smoothing ripple or providing peak current that you power supply can not. The P-channel MOSFET adds a little voltage drop through the circuit, but just a little, so my only guess is that the power supply you are using has marginal capability to begin with. Let me know what else you find.

Ruedi Heimlicher, 2014-05-15 11:04

Hi and thanks for your response. The problem was the P channel MOSFET I was using on my breadboard. I read somewhere that the circuit also works fine with discrete MOSFET's, but the P type I had lying around had a threshold voltage of 2 to max 4V, and that apparently was too much. The PCB with the IRF7319 works now fine. I used a regulated power supply delivering 5V, and the output looked fine on the (100MHz)scope.

Paul Clifford, 2014-05-15 15:59

Reudi, Glad it's working now. Yep, the MOSFET specs really do matter! Using a supply of 5V, the P-channel of the IRF7319 will drop well less than 0.1V with currents up to 3A, so it's a good choice. Many newer MOSFETs have very low rDS_ON, much lower than MOSFETs available ten years ago.

Alex, 2014-03-20 19:15

Fantastic schematics and explanations, but I would like to find out if:

1. This circuit would still function at 3.0 to 4.2V supply voltage (used to drive the ENABLE line of an LVDO)

2. A 1s delay Power-ON delay could be introduced instead of a short press

3. Does this switch configuration effectively debounce it?

Thank you so much, Alex

Alex, 2014-03-21 01:38

Apologize for not referencing the circuit in question - the Raspberry PI ON/OFF controller:

http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/raspberry-pi/on-off-power-controller

Thanks again!

Paul Clifford, 2014-05-14 19:12

Alex,

1. The circuit should still function down to 3.0V. The MOSFET pair specified, the IRF7319, has gate threshold voltages of about 1V for both MOSFETS. The IRF7319 datasheet shows detailed specs down to 3V. The series pass MOSFET can provide 1.5A with a 5V supply, but considerably less than 1A at a 3V supply. That won't work very well if you want to get a lot of power through it, but if it's used just to drive an ENABLE line it would work fine, even at much lower voltages. If you want to pass a lot of current at lower voltage then it's best to use separate MOSFETs. You can choose a series pass MOSFET that can provide more current at a lower gate-source turn-on voltage, and operate down to much lower voltages. For example, the SSM3J304T can provide more than 2A current with a voltage drop of less than 0.2V, at a power supply voltage of 2.5V.

2. You can add a 1 sec turn on delay (requiring that the switch be pressed for 1 sec before the circuit responds) if you use separate on and off switches, but it's trickier if you want to retain only one switch. I see if I can come up with a reliable circuit; if so, I'll post it.

3. Yes, this switch configuration debounces the turn ON/OFF perfectly.

Best regards!

Nick Guerette, 2014-10-01 21:54

Hi Alex — see this comment above for one option for a circuit allowing a delay in both turn-on and turn-off.

J. Lane, 2014-02-28 18:32

What kind of caps are those in figure 6? Are they ceramic? I noticed they are not polarized.

Nick Guerette, 2014-03-13 16:40

Yes, in general non-polarized capacitors on our boards are ceramic chip capacitors, most commonly 0603 package X7R type with 20% tolerance, but sometimes larger packages for higher capacitance or higher voltage limits, or tighter tolerance for timing circuits.

K. Nelson, 2014-02-07 19:00

Greetings,

Thank you for the instructive circuits and tutorials. I intend to build an on/off circuit for an RPi - 2 questions

1. The diode is labeled as a BAV99, which is a switching diode array, not a single diode as pictured in your circuit. Is this really the correct part number? 2. The Auto ON/Auto OFF jumper is not quite clear as it is explained, although I think I am reading the diagram correctly. If the switch is set to ground, then the circuit will always default to ON, until it is turned off with the momentary button. Is that correct?

Thank you for your help.

-K. Nelson

Nick Guerette, 2014-03-13 16:59

1. Yes, in this case we're just using one of the two diodes in the BAV99 part. It's inexpensive enough that from an inventory management perspective, it's simpler to use this part both where two diodes in series are needed and where a single diode is needed, rather than stocking a separate part for single diode applications. From a technical perspective, any silicon diode will work in this application.

2. Yes, you are correct. The Auto ON/Auto OFF jumper only affects what happens when external power is initially applied; shortly after power is applied the 0.1uF capacitor charges and then the circuit is controlled by the On/Off switch.

mustafa bayraktar, 2014-02-06 16:27

Dear Sir;

I have a program about writing & reading from RS232 however it drops bytes and I really cannot read what i write what can be the issue? Can it be related to my low ram which is only 1024 best

Nick Guerette, 2014-03-13 17:01

For this issue I suggest looking to online forums for general programming questions, such as: http://stackoverflow.com/

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