Thanks for the replies!
Sorry for the schematic, I tried to keep it simple but it made things a little more confusing
Attached the complete schematic and a photo of a sensor so you can see.
What I’m trying to make?
A ‘‘box’’ where you attach the sensor and do the measurements.
At work we assemble these sensors, after the assembly is done we test them to see if they are within the specified specs.
We already have a ‘‘box’’ that does that, but it’s pretty old (for example you have to connect multimeters to able to read the measurements) and i think i can make a new one that does the same, looks a bit better and you dont have to connect any multimeters to it.
How did I come up with the schematic?
I opened the ‘‘box’’ and made a schematic of the wiring. When I had that, i was able to find out what the test ‘‘box’’ actually does.
What does the test ‘‘box’’ do?
It’s actually pretty simple. It simply measures the output of each phototransistor across a 1k resistor, at a specified voltage.
What is this ‘‘specified’’ voltage?
According to the instructions to test the sensor, you have to measure 4.5v across the 80ohm resistor which is connected to the IR-led. You get the 4,5v by adjusting the resistance of the potmeter.
When you have that settled, you measure the outputs of the phototransistor and see if they are within the given specs. When they are ok, you can proceed to the last step, which is; lowering the voltage again, with the help of the potmeter, until you read 70mV coming out of one of the phototransistors. Then you read the voltage across the 80ohm resistor. This voltage should be between 0.15-0.45v, and it’s written on a sticker and placed on the sensor.
What do i got now?
After making the schematic I attached, i build it on a breadboard to see if it did the same as the old box. To my surprise it worked in one shot!
so what’s left is the building part. My first idea was to place voltmeter modules where you see the multimters on the schematic. After doing some more research i came across LCD display modules, now I think that a LCD display that displays 3 voltages (Vout1,Vout2, Vrled) would be a smarter/better solution for what i want.
Is this possible with a single arduino? If yes, how doable is it? i have messed around with arduinos before, so I do have some ecxperience, but it’s been a while since that. Or would it be more reasonable to put the 3 voltmeter modules?
P.S the resistors across which we measure(1K,1K,80ohm), are part of the test ‘‘box’’. They dont form part of the sensor itself.