✧˚⋆ DEVLOG 7: I have finally succeeded in setting up the photodiode system! It now outputs signal value ranging from 97-350, and filtering out almost all noise. This required re-programming the way in which output signal is detected, as heavy 120Hz noise was present, and rewiring until the best result (so far) was acheived. This allowed me to complete the project’s main goal: magnetostriction effects observed in a nickel rod! This is despite amplification still not being fully maximized. (theo. max: 1023)

To test this, I wrapped a 25ft copper wire around the solenoid cover and connected it to a DC power supply. As current is turned up, the photodiode signal has been decreasing repeatly. (See photo - output decreases by ~1-2)

In the pulse test, it is also shown to decrease instantaneously, and when the photodiode is covered, no parasitic effects from the current are present, leading me to believe that the observed effect was truly caused by fringe shift due to magnetic shrinkage caused by the solenoid.

For this reason, this may very well be my last devlog! There is still room for improvement in fine-tuning the amplification system, but the full functionality of every component has been demonstrated. It however doesn’t mean I’m done with the project at all after shipping - I can try out rods with different metals and higher currents with amplified signal to get and compare ‘true’ quantitative data in the future!
Check out README.md for more details!