In the last weeks, I have been fixing artifacts in the signal, I was doing experiments with LASER modulation and with DMA data transfer on Raspberry Pi v2.
Fixing Existing Circuit
I was facing artifacts in the signal before entering A/D conversion. A new operational amplifier fixed it. See artifacts below:
The solution was to change operational amplifier LM324 -> TL084, see signals below (it’s the same circuit, but LM324 was replaced by TL084)
1) LASER intensity modulalation
2) DMA data transfer on Raspberry Pi
I have fractional results in both: LASER modulation and DMA data transfer on Raspberry Pi v2. I plan to boost the vibrometer to a new level, but I have nothing big to show right now. I wonder what to change in the next generation (e.g. MCP3008, Arduino Nano, TRCT 5000, 9V battery supply).
I have big plans, but I think in reality I’ll replace the 9V battery with a filtered USB supply and place the PCB into a box 🙂
https://github.com/TomasGaj/Arduino_vibrometer/
Enjoy!
Tomáš Gajdarus
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