... I mean I hoped this would be the response but i didn't think it would actually happen. A short article the project but there really isn't more to say https://hackaday.com/?p=587271 and also talked about on the podcast https://hackaday.com/?p=588642 (16 minutes in for 2 minutes) complete with messing up my name thus giving me a new name. Thank you.

Special thanks to Kuba Sunderland-Ober who gave great suggestions in the comments. In the long run i will be trying to implement the 2 color LED and adjustable reference points but for now i will try to

a) control LED current and

b) turn it into a PCB

so. 

Current control

right now the setup for one led looks like this.This simply will not do. An alternative to this was pitched with a separate voltage source for the LEDs from the OpAmps and a transistor but i asked around an got this The OpAmp has enough oomph to supply the current.

The PCB

I'm using KiCad for this. Nothing interesting to show jet but i'll talk about some things i'm thinking about.

• connection to the breadboard

my last method was...unreliable. I am considering a spring loaded connector that feels like it could get pricey but i am not clever enough with mechanics to come up with an alternative so i might have to bite the bullet.

• power

last time it was a LiPo battery connector but needed to be driven from a controllable power supply because i added it last minute. This time i'm thinking USB connector.

• negative voltage?

for the opamps when the signal is close to 0V.