May 27, 2026
After our visit to the CTN, we were originally planning to add an inverter and amplifier to condition our pulse signal. But after taking a closer look at the measurements, we realized we actually didn’t need either of them.
What We Found
While we were at the CTN, the signals we were measuring directly on the Geiger tube were very small pulses, since that was the part of the system we were testing at the time. Later, we discovered that the driver board already amplifies the signal and adds a voltage offset to it automatically.
That means the output coming from the board is already well within range for our ADC — sitting at around 3V at rest and dropping close to zero on each pulse. Perfectly usable without extra amplification.
The image shown in this blog post is one of the real Geiger pulses we captured during our visit to the CTN.
The Fix
Instead of adding more components, we simply adjusted our measurement approach. We set our zero reference at 3V and configured the system to count a pulse whenever the signal drops below a certain threshold. Simple, clean, and effective.
The Result
Everything is working really well. The signal is clean, the pulses are being counted correctly, and we avoided adding unnecessary complexity to the circuit. Sometimes the best engineering solution is the simplest one.
The prototype keeps getting better.