LEAP: Little Electronic and Arduino Projects

A small boost converter module based on the SX1308 IC, with output adjustable up to 28V from input 2V~24V DC.

Low-cost boost converter modules based on the MT3608 IC, with optional micro USB input connector, and output adjustable up to 28V from input 2V~24V DC.

A micro boost converter module based on the ME2108 IC, with a fixed 5V output from operating input range of 0.9V~6.5V.

Reviewing a range of low-cost boost converter modules that can generally supply up to 30V.

Testing an interesting upside down astable 555 configuration that achieves +duty cycle control all the way down to 0% without an additional inverter stage.

Building and testing the TJ-56-719 code practice kit.

The most minimalist acoustic levitation demo using an Arduino Nano to drive a pair of TCT40-16 ultrasonic transmitters.

Using an Arduino to automatically determine the polarity of ultrasonic piezo transducers.

Reviewing some common 40kHz 16mm ultrasonic transmitters and receivers TCT40-16T/TCT40-16R, including methods for testing polarity.

Review and test the 433MHz remote control unit 2202J that features two relays, can operate on mains AC or 5V USB, and can be programmed to behave in momentary, toggle, latching, mixed, or motor control modes.

Testing some push-button switches with built-in LEDs.

A 3x3x3 LED cube animated with 512 different patterns generated by a 555 timer and CD4020 binary counter.

Introducing the CD4020 14-stage binary counter with a basic demonstration circuit.

Demonstrating the most minimal 555 oscillator configuration requiring just a single capacitor and resistor.

Introducing the CD4024 7-stage binary counter with a basic demonstration circuit.

Investigate acoustic levitation by building a cheap ultrasonic levitator kit that uses common 40kHz ultrasonic transmitters driven by STC15F101W microcontroller and a TC4427 power MOSFET.

All about double-pole, double-throw (DPDT) non-latching/momentary push-button switches.

A little 1d6 or 2d6 dice roller using the TM1638 and ATtiny85.

Celebrating the 55th birthday of the most evergreen IC of all time: the 555 timer, with a reproduction using discrete components.

Demonstrating how a DEMUX gate may constructed solely from NAND gates.

Demonstrating how a MUX gate may constructed solely from NAND gates.

Demonstrating how an XNOR gate may constructed solely from NAND gates.

Demonstrating how an XOR gate may constructed solely from NAND gates.

Demonstrating how a NOT gate may constructed solely from NAND gates.

Demonstrating how a NOR gate may constructed solely from NAND gates.

Demonstrating how an OR gate may constructed solely from NAND gates.

Demonstrating how an AND gate may constructed solely from NAND gates.

Reverse-engineer a faulty YLD8-12X1W LED driver, diagnose the issue, but determine the fix is not worth the effort.

Using the new Open HamClock Backend (OHB) to give my HamClock client installation a new lease of life.

Using the PLA 3D printing services available in Singapore's National Libraries - Bambu Lab P1S.

Building a 4-pole exclusive interlock using the CD4028 BCD to Decimal decoder, with a simple LED switching demonstration.

Using an Arduino to interactively solve cassidoo's interview question of the week (2026-02-09): using a rotary encoder to enter an array on an LED 8x8 matrix, dial-in a target digit on a 7-segment display, and then let it animate the recalculation of the…

All about configuring the I²C on the Raspberry Pi.

A simple DIY adapter for the Raspberry Pi to mount the hardware for the BME280 environmental sensor, satellite, alarm, and countdown controls and indicators.

Examine the BME280 barometric pressure, temperature, and humidity sensor.

Examine the BME280 barometric pressure, temperature, and humidity sensor.

Review a common 12-16.8V DC to 220V DC boost converter module.

Examine the BMP180 barometric pressure and temperature sensor.

Examine the BMP280 barometric pressure and temperature sensor.

A common LM2596S-based buck converter module with adjustable-voltage control, operating at around 50kHz switching frequency.

Another common LM2596S-based buck converter module with adjustable-voltage control, operating at around 50kHz switching frequency.

An XL4015-based buck converter with adjustable-voltage control and selectable input/output voltage display.

A common MP2307DN-based buck converter module that is extremely small and convenient for relatively low-power requirements under 17V.

Testing an XL4015-based buck converter with adjustable voltage and current controls and display.

Demonstrating the 74LS47 7-segment common-anode LED driver with a simple 4-bit binary counter sequence.

About the 74LS161 4-bit Binary Counter with Asynchronous Reset, illustrated with a simple counter demonstration.

Building the CHA-81 LED Matrix Soldering Kit and investigate the principles of operation.

Logging temperature and humidity with an Aosong AM2301 DHT21 sensor.

Using the Adafruit Unified Sensor Library to log temperature and humidity from a DHT11 sensor.

Logging temperature and humidity with DHT11 sensor.