Course project · Team of 2·Mar 2026Complete
AC Phasor Voltmeter
Dual-channel AC instrument on the EFM8LB12 measuring frequency, DC offset, Vrms and phase difference.
A dual-channel AC measurement instrument built on the EFM8LB12F64 in C, using the 14-bit ADC to measure frequency, DC offset, Vrms and the phase difference between two signals, with readings shown on an LCD and streamed over UART.
Highlights
- Measured phase by timing the gap between rising zero-crossings with Timer 0
- Used a hysteresis band around each signal's DC midpoint to avoid false triggers from noise
- Added frequency-mismatch and no-signal fault handling, plus a debounced mode button cycling LCD screens
Gallery
