ivanov.asen
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Joined: Thu May 10, 2018 1:03 pm

BrightPi IR leds not working

Fri May 11, 2018 12:47 pm

Hi guys,
I'm writing in the forums to get your ideas and suggestions on a problem I'm facing with my Bright Pi. As the title briefly describes it - I got a Bright Pi along with a RPi3 and a NoIR camera. I have searched this forums and the internet for possible solutions but everything I tried didn't seem to work. Below is a brief summary of what I have done so far:

- soldered leds to board cleanly without burning any of the components;
- short leg (-) soldered to where the arrows point as per the instructions;
- camera configured and works just fine, no issues there;
- wiring done properly, double & triple checked
- I have updated/upgraded raspbian on the RPi, i2c enabled, i2c tools installed, system detects the board;
- dtparam=i2c1=on & dtparam=i2c_arm=on added to /boot/config.txt;
- i2c-bcm2708 & i2c-dev added to /data/etc/modules;
- /etc/modprobe.d/raspi-blacklist.conf existed but it was blank but I added #blacklist spi-bcm2708 and #blacklist i2c-bcm2708 anyway;
- sudo i2cdetect -y 1 shows a device at 0x70;
- white leds work properly, brightness can be adjusted;
- power supply is 3.1A, which should be more than enough for powering the device + camera + bright pi.

Whatever I do, IR leds do not light up. I'm checking with a mobile phone camera + a test in a dark room with an object close to the camera (50 cm). I'm now running out of ideas, does anyone have any suggestions!

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mahjongg
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Re: BrightPi IR leds not working

Fri May 11, 2018 5:08 pm

The datasheet for the semtech SC620 chip is here.

https://www.google.com/url?sa=t&rct=j&q ... td11q5jIiP


The only quick explanation I have for a case where the IR LED's are not lighting up is that the IR LED's are mounted in reverse.
Also, I don't see a full schematic, but if there are two IR LED's in series, it could be that their combined forward voltage is larger than the power voltage.

so measure with a multimeter the voltage over the IR LED's, and debug the thing.

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Re: BrightPi IR leds not working

Fri May 11, 2018 6:02 pm

Remove i2c_bcm2708 from etc/modules. Device tree does all the necessary steps to load the driver once you've added dtparam=i2c_arm=on or dtparam=I2c1=on (they're synonymous).
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ivanov.asen
Posts: 3
Joined: Thu May 10, 2018 1:03 pm

Re: BrightPi IR leds not working

Sat May 12, 2018 5:26 pm

Thanks guys, today tried both removing the i2c_bcm2708 from /etc/modules and reversing the leds... still not working though...

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mahjongg
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Re: BrightPi IR leds not working

Sun May 20, 2018 7:45 pm

use a multimeter to find the fault.

ivanov.asen
Posts: 3
Joined: Thu May 10, 2018 1:03 pm

Re: BrightPi IR leds not working

Mon May 21, 2018 8:51 am

Thank you all for the ideas!

I used a multimeter and everything seemed to be working - so my guess is that there is something wrong from the software side.

I have ditched the Bright Pi without finding what was wrong. I got 6 new leds plus a couple of resistors and connected them directly to the 5v on the RPI + an small on/off switch and everything works perfectly (for ~3 EUR :D )

Now I'm wondering why I even decided to go for the Bright Pi... and what's the role of the i2c interface for a simple IR lighting...

Anyway, thanks again for all the suggestions!

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