An expansion board is a carrier that a small dev board plugs into, so its pins come out as rows you can push leads onto instead of using a breadboard. This one takes the ESP32-C3 SuperMini in two 8-way sockets and brings all 13 of its GPIO out as 3-pin rows of signal, VCC and ground, the same layout servo and sensor leads use, so a 3-wire lead plugs straight on with nothing to solder.
Use it to wire servos and sensors on a small robot, build a battery-powered ESPHome sensor, or replace the breadboard in a classroom kit. The ESP32-C3 SuperMini is sold separately and needs male header pins on it to seat in the sockets, so choose the Pre-soldered version if you want it to drop straight in. Both VCC rails give 3.3V as shipped, and a 3 x 3 power block adds three taps each of 5V, GND and 3V3, with the 5V taps live only while the SuperMini is on USB-C. A PH2.0 socket and B+/B- pads underneath take a single 3.7V lithium cell, and the board charges it while the SuperMini is on USB-C: the green BAT-LED stays lit while it charges and goes out when the cell is full. Use a protected cell and check the polarity before plugging it in. The pins run at 3.3V, so level-shift any 5V signal, and give servos their own 5V supply with the grounds joined, using the row for the signal wire only.
Specifications
Datasheets
Wiring & getting started
- Fit header pins to your SuperMini
Solder male pins to the SuperMini pointing down on the side without the buttons, or use a Pre-soldered SuperMini, which drops straight in.
- Seat it the right way round
Unplug USB-C first and leave servos, sensors and any battery off. Hold the SuperMini buttons up with its USB-C socket pointing towards the white battery connector, so its 5V, GND and 3V3 pins sit beside the blue, black and red power block. All 16 pins go into sockets with no empty socket at either end. Press straight down on both edges until it sits flat. Seated the other way round, the supply lands on GPIO21, so if the module gets warm or USB drops out, unplug it and reseat it.
- Load the row test
Plug USB-C into the SuperMini, as the carrier has no USB socket of its own. In the Arduino IDE choose ESP32C3 Dev Module, set USB CDC On Boot to Enabled, pick the port and upload the row test sketch from the Quick Start guide above. Open Serial Monitor at 115200.
- Check it works
The SuperMini's blue LED blinks and Serial Monitor repeats "GPIO5 HIGH: jumper off". Put a female-to-female jumper between the yellow and black pins of the GPIO5 row, the first row on the left flank at the battery end. The LED goes steady and the monitor shows "GPIO5 LOW: jumper on". If the jumper changes nothing, check you are on the GPIO5 row and using the yellow outer pin and the black inner pin, not the red middle one. If the board will not start with a lead plugged in, something is holding GPIO2, 8 or 9 at power-up, so move that device to another row.
- Plug in servos and sensors
Push each 3-wire lead on with its signal wire to the outer edge: orange, yellow or white to yellow, and brown or black to black. The colour order is mirrored between the two flanks, so go by the label at the end of the row. Run a servo's red wire from its own 5V supply and join that supply's negative to a black GND pin.
- Change a rail to 3.7V (optional)
Only if a part needs it: remove that rail's 0R resistor and bridge its three pads with solder. The datasheet shows which pads. Check that flank's red row against a black pin with a meter before reconnecting anything. The other flank stays at 3.3V, so keep 3.3V-only parts on that side. Refit a 0R link to change it back.