iSynthetixx
Posts: 1
Joined: Sat Feb 29, 2020 12:36 am

Stepping down 12V 2A to use on GPIO input

Sat Feb 29, 2020 12:45 am

Hello, I have a some hardware that controls large signal lights. I would like to use an opto isolator or something similar to connect to the pie’s GOIO to be able to know when the signal lights are on. The hardware drives up to 10 signal lights, so I would like to have 10 GPIO inputs. Can anyone recommend some hardware to assist in this?

Basic goal is for the pie to know when each of these signals is on or off.

PhatFil
Posts: 1672
Joined: Thu Apr 13, 2017 3:55 pm
Location: Oxford UK

Re: Stepping down 12V 2A to use on GPIO input

Sat Feb 29, 2020 2:08 am

simplest solution afaik would be to use light sensitive resistors, if you can use putty or epoxy to mask off ambient light so the LDR s can only react to your specific light sources it should be pretty straight forward to monitor 10x devices
1st result for a search "LDR Pi circuit"
https://pimylifeup.com/raspberry-pi-light-sensor/

pcmanbob
Posts: 9270
Joined: Fri May 31, 2013 9:28 pm
Location: Mansfield UK

Re: Stepping down 12V 2A to use on GPIO input

Sun Mar 01, 2020 9:52 am

Hi.

Yes you could do it using opto isolators but as you have 10 lamps you would need one opto isolator for each lamp.

As long as the lamp are powered with 12V DC you can connect the opto isolator for each lamp like this

Image

You can use any opto isolator you want but any in the 4N25,26,27,28 or 4N35,36,37 will work
We want information… information… information........................no information no help
The use of crystal balls & mind reading are not supported

Return to “Interfacing (DSI, CSI, I2C, etc.)”