Pico: Two Temperature Sensors That Keep Their Names
Read two DS18B20 sensors on one Pico pin. Keep physical channel names tied to ROM IDs and report missing sensors, CRC errors and reset ambiguity.
Author: Tricky Circuit
Raspberry Pi Experiment Log: Keep the Last 1000 Readings
Build a Raspberry Pi SQLite log that keeps the latest readings, separates sensor errors from zero and rolls back interrupted transactions.
CD4017: Build a Ten-Step Light Sequencer and Catch an Extra Count
Build a 5 V CD4017 light sequencer with a TLC555 clock. Calculate timing and LED current, test reset and discover how inhibit can add a count.
SN74HC14: Debounce a Button and Measure Hysteresis
Build a button conditioner with TI SN74HC14N. Calculate unequal press and release delays, measure hysteresis and test the limits of RC debounce.
MiniMeter: Four Voltage Points and the Time-Skew Experiment
Monitor four low-voltage nodes with a Pico and ADS1115. Build separate input dividers, calibrate each channel, and see why sequential readings differ in time.
Build a Pico Mini Multimeter for Low-Voltage Experiments
Build a battery-powered Pico meter for 0–12 V DC, resistance and continuity. Learn input loading, calibration and fault handling with complete code.
Read Resistor Colour Bands: 4, 5 and 6 Bands Explained
Read resistor colour bands, resolve the reading direction, calculate tolerance, and check loose resistors with a meter. Includes examples and common traps.
ESP32 I2C Detective: Missing Device, Duplicate Address or Stuck Wire?
Inspect a 3.3 V I2C test bus before scanning. Separate missing acknowledgements from stuck lines, demonstrate address collisions and attempt bounded open-drain recovery.
Pico Fan Tachometer: Count Pulses Without Guessing the Interface
Read the documented tach output of a 5 V Noctua fan with a Pico. Calculate RPM from two pulses per revolution and distinguish no pulses from a diagnosed stall.
Arduino Marble Timer: Two Light Gates and an Honest Speed Estimate
Time an opaque ball between two optical gates on an Uno. Check event order, reject incomplete runs and calculate average speed with spacing and sensor-delay uncertainty.