Inverting and scaling

Fiddling a little (I don’t have a fiddle) with the resistors for the opamp, I finally ended up with this:


It’s the thorlabs logo again, covering the TCD1304. The opamp (AD8027) has scaled end shifted the output to match the ADC’s range. Zero light corresponds to 145mV and full saturation is around 3.23V.

I don’t think I can get closer to 0-3.3V than this without buying fancier resistors. The values are:

R₁ = 510
R₂ = 1k
R₃ = 620
R₄ = 510

for this:


Not exactly what LTspice suggested, but who cares.

Oh yeah and with everything soldered up, it looks like this:


Pin headers for the GPIOs and u.fl. connector for the analogi input.

Did I mention USB is working.. someday soon I’ll have the firmware ported to the STM32F405 🙂


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