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by geerttttt
Mon Oct 23, 2017 5:18 am
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

Ok, so switching on the ground is a bad idea? I read that with a Mosfet you always have to swith the ground pin, not the plus wire. I thought it made sense, otherwise where is the ground wire for the gate? Check out the P-channel mosfet switch circuit here (some way down the page). Use an NPN bipol...
by geerttttt
Sun Oct 22, 2017 11:08 am
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

I assume that, according to what you wrote, the MOSFET switching the H-bridge is different to the one shown "controlling" the 10V-out 2-pin connector. HOWEVER: I think that the MOSFET shown has source and drain either wrongly labelled or actually reversed. Bad move. More seriously, it is bad practi...
by geerttttt
Fri Oct 20, 2017 6:00 pm
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

If you had the resistor connected to3.3v at one end and the photo resistor connected to the other end and it's other lead connected to ground you should not have had a problem as even if the photo resistor was a dead short the 10k resistor would have limited the current to 0.3mA. Done all the time ...
by geerttttt
Sun Oct 08, 2017 5:53 pm
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

Just put a bit of coloured tape over the pot covering the top completely, much easier to remove should you need to later and it will still prevent you from making silly adjustments. :D I'll do that, good tip! Im trying to build on now that my GPIO pins are protected. But... I got a good scare today...
by geerttttt
Thu Oct 05, 2017 1:47 pm
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

So, i soldered it on there, and Yay! The pi lived trough it. It's working nicely, so i hope it's gonna stay that way. Gonna have to put a bit of hotglue on the potmeter for the voltage though... if i accidentaly twist it, pi = dead! I have it powered via the GPIO now, so no seperate usb connector or...
by geerttttt
Thu Oct 05, 2017 9:23 am
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

Hi. I use the LM2596 variable voltage step-down DC-DC converter when ever I need to power a pi from a battery or some power source with a voltage higher than 5V. if you have another one of the ones already on PCB then that will work just fine, got an original pi B and a pi2 running off them without...
by geerttttt
Wed Oct 04, 2017 6:33 pm
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

When the probe is plugged into the 10A socket only the 10A range will give a meaningful reading. For the other ranges to work it needs to be plugged into the VmA socket. (some meters have a separate socket for the mA range as well). Test on the 10A range first and only try on the other ranges if it...
by geerttttt
Wed Oct 04, 2017 1:46 pm
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

looking at the currents drawn if you were on the 200mA range then 0.05 is 0.05mA or 0.00005A which is fine, but your 5v looks odd if you were in fact on the 20ma range ? I would have expected a load of 0.5A on the 5v which is what you figures show are you sure you were not on the 10A range, which w...
by geerttttt
Wed Oct 04, 2017 7:23 am
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

I did some new tests now that i connected the raspi 3.3v to the board. Also i changed the input voltage from both the ADS1115 (ADC chip) from 5v to 3.3v and for the 5 IR Led phototransistors also. Now the voltages are way better. On no pins i have measured anything over 3.3v. And the 3.3v pin measur...
by geerttttt
Tue Oct 03, 2017 2:37 pm
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

It was around 5v, 4.98 if i'm correct. I would consider that a bit low if you had no load on the dc-dc converter. I would expect to see 5.1-5.2v no load. Don't think i really understand what you mean. How to find out what my pi is actually drawing? OK lesson time.... How to measure current drawn by...
by geerttttt
Tue Oct 03, 2017 12:07 pm
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

Can someone give me advice on the setup? I see some strange things. especially GPIO 3 and 2 read 4.5v! Those are connected to the ADS1115 (it's an ADC) with 5v. I suppose i should change that to 3.3v, didn't know it would also supply around 5v to the i2C pins... But... That can't be the real proble...
by geerttttt
Tue Oct 03, 2017 12:04 pm
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

With regards to the 5v problem. Do some testing. 1. what voltage do you get on your 5v rail without the pi connected ? It was around 5v, 4.98 if i'm correct. 2. put an amp meter on the output of your dc-dc converter and see what current is being drawn, compare this to what your pi is actually drawi...
by geerttttt
Tue Oct 03, 2017 10:31 am
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

I don't think putting 4.5v on any gpio pin will do you pi any good , it may survive for a while but eventually its libel to do some damage. I agree, but both Pi's died instantly when plugging them in. While that connection has worked for days... also you seem to show a voltage of 3.98v on a ground ...
by geerttttt
Tue Oct 03, 2017 8:12 am
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

Ok, i'm trying to read and understand this. You're saying all GPIO pins already have clamp diodes? Also on the zero? So overvoltage is impossible? So only a simple resistor on every channel is all it takes to protect them from situations like this? I'm saying that a high enough value of series resi...
by geerttttt
Mon Oct 02, 2017 5:41 pm
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

Ok, so a resistor in series would limit the current enough? And how to prevent overvoltage? A Zener diode maybe? And also, i have 10 schottky diodes on the way, should arrive this week. Would it be of much use to put those between every gpio i use? At least to the output pins to prevent current fro...
by geerttttt
Mon Oct 02, 2017 4:58 pm
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

If there was an overvoltage (which seems the most likely) the Pi0 is probably irretrievably dead. :cry: The PiA+, however, may just have a short-circuit on the protection Zener diode (D5, see schematic ). Test the Pi with it removed (do NOT connect any GPIO wiring, just the minimum screen/keyboard/...
by geerttttt
Mon Oct 02, 2017 10:53 am
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

Small update from my part. When i up the amps on my bench power supply the voltage also rises, but it still is grabbing max current. For example, at around 1.5A the voltage level is around 4v. But... it actually uses 1.5A or whatever i give it, that doesn't seem good to me.
by geerttttt
Mon Oct 02, 2017 10:03 am
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

Well, apart from the fact that I can't correlate the schematic with then actual wiring for the supply to the 10V step-down, have you checked that the voltage out of the 5V step-down is correct without a Pi (or anything else) connected? Similarly for the 10V, though that shouldn't affect the Pi unle...
by geerttttt
Mon Oct 02, 2017 9:47 am
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

First i booted it with a usb power supply, was booting fine, power led was on etcetera. Afterwards i tried to boot it with some of the gpio parts connected. I thought the A+ had more power protection, but this board died in the same way :shock: How is the power connected for the second test? If you...
by geerttttt
Mon Oct 02, 2017 9:41 am
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

Re: No PWR led, ACT led very dim and gets hot! (A+)

HI. If both your pi's died when you connected some external components to the GPIO then what you connected has to be the suspect for the cause. either you have a short circuit on your external set-up or it is drawing to high a current from 3.3v or 5v, or you are putting more than 3.3v on to the GPI...
by geerttttt
Mon Oct 02, 2017 9:08 am
Forum: Troubleshooting
Topic: No PWR led, ACT led very dim and gets hot! (A+)
Replies: 44
Views: 3701

No PWR led, ACT led very dim and gets hot! (A+)

Hi, I have a project where i'm using my raspberry pi for. i was using a pi Zero for this. It was all working fine until yesterday, when i tried to power it and somehow it died. On the pi Zero there is no power led, so all i saw is that it didnt start booting. Also it got pretty hot pretty fast aroun...
by geerttttt
Wed Apr 15, 2015 1:53 pm
Forum: Advanced users
Topic: 3.6" TFT fbtft help
Replies: 3
Views: 2572

Re: 3.6" TFT fbtft help

I bought the same device. Which software image did you had to run it? I only got some source code to display a image as you had aswell. Did you do anything with the display? And, what was the framerate? Was it really bad? I need to display a GUI on it with some animations, but mostly nothing too hea...

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