[joezydeco]

I was focusing more on the "current to frequency" stage, which looks like an empty IC socket. As is the "pulse width counting" stage just a bunch of header pins?

I mean yeah, I get it, it's a prototype and a finished product will be on a $2 ASIC to drive the correct signals and etc. But I'm not up to speed on affinity sensors vs. traditional ELISA tech so <internet shrug>.

[lambdaone]

Nothing jumps out at me as being fishy here. There's what appears to be a small device mounted in the middle of that empty socket. It's also possible some of the rest of the pins on the socket are being used as test points. A circuit diagram would have be good to have here.

[dtgriscom]

Yeah; it's a bit strange to label a single MOSFET...