Tools for electronics and IoT projects
Free calculators and references for ESP32, Arduino and Raspberry Pi Pico projects: from identifying an SMD part to sizing a solar system. They run in your browser, with no sign-up.
Deep Sleep Budget
How long your ESP32, Arduino or nRF node lasts on a battery, and what is draining it.
Open the calculator →ESP32 pinout
Which GPIOs are safe, which are strapping or input only, and which ADC pins stop working with Wi-Fi.
Open the pinout →Raspberry Pi Pico pinout
Where each I²C, SPI, UART and PWM signal can go, with a planner that checks your choices.
Open the pinout →DC wire size
The cable cross-section for a 12, 24 or 48 V load, with voltage drop and power lost in the wire.
Open the calculator →Off-grid solar sizing
Battery, panel and charge controller for a cabin, a camper or a remote sensor station.
Open the calculator →ESPHome config generator
A ready-to-flash YAML for ESP32 and ESP8266 boards, with sensors, relays and deep sleep.
Open the generator →SMD component identifier
What that tiny part is: shape, size and the code printed on it, checked against 400 datasheet codes.
Identify a part →Resistor colour and SMD codes
Colour bands and SMD codes like 103, 4R7 or 01C, in both directions, with tolerance.
Open the calculator →LED resistor
The standard resistor for one or more LEDs, with the real current and the power it handles.
Open the calculator →Voltage divider
Output voltage, or the best standard pair, with ADC limits for measuring a battery.
Open the calculator →PCB trace width
How wide a trace must be for its current, on outer and inner layers.
Open the calculator →I²C address checker
Addresses of 76 sensors and chips, conflicts on your bus and the pull-up resistors.
Check your bus →Runs in your browser
Nothing to install. The values you enter stay on your device.
Formulas in plain sight
Every tool explains how the result is calculated and which assumptions it makes.
Built from datasheets
Presets use typical values from manufacturer datasheets. Replace them with your own measurements.