Wiring

Wiring

You'll need: the parts, soldering tools, an adult helper if you're under 16 · Time: 1–2 hours

⚠️ Unplug USB and the battery before you start. Read Safety first.

The plan

flowchart LR
  F["Prop-Maker Feather<br/>(brain + sensor + amp)"]
  W["Servo FeatherWing<br/>(PCA9685)"]
  F -- "stacked on top (I²C)" --- W
  W -- "channel 0" --> RW["Right wing servo"]
  W -- "channel 1" --> LW["Left wing servo"]
  W -- "channels 2, 3, 4" --> ME["Main eye (R, G, B)"]
  W -- "channels 5, 6, 7" --> SE["Small eye (R, G, B)"]
  F -- "EXTERNAL_NEOPIXELS pin" --> WL["White LED"]
  F -- "speaker terminals" --> SP["Speaker"]
  F -- "JST battery plug" --> B["LiPo battery"]

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The channel numbers matter. The firmware expects each part on exactly this channel. The full table is on the Channel map.

Steps

1. Solder headers onto the Feather and the FeatherWing so they stack. Follow Adafruit's guides for the Prop-Maker Feather and the Servo FeatherWing.
2. Stack the FeatherWing on the Feather, matching the pin labels.
3. Plug the right wing servo into servo header 0 on the FeatherWing. The brown (or black) wire goes to the pin marked GND.
4. Plug the left wing servo into servo header 1, the same way round.
5. Wire the main eye: red leg to the PWM pin of channel 2, green to 3, blue to 4, and the long shared leg (cathode) to GND.
6. Wire the small eye: red to channel 5, green to 6, blue to 7, shared leg to GND.
7. Wire the white LED to the Feather's external NeoPixel connection (EXTERNAL_NEOPIXELS) and ground, with a resistor in series.
8. Connect the speaker to the Feather's speaker terminals.
9. Power for the servos: give the FeatherWing's servo power terminal the supply your build uses.
10. Plug in the battery last.

✅ It should look like this

• Servo 0 is the right wing and servo 1 the left wing (looking from behind the droid).
• Every LED's shared leg goes to GND.

⚠️ Something went wrong?

Check these once the firmware is on (Copy the firmware):

Problem	Likely cause
A wing doesn't move	Servo plugged in backwards, or on the wrong header. Check brown/black is on GND.
The wings move the wrong way, or the left one moves like the right	The servos are swapped: right wing must be on 0.
An eye is the wrong colour	Two colour legs swapped. Red should be on the lower channel number.
An eye is bright when it should be dark	You have a common-anode LED. Use common-cathode ones.
Nothing happens at all, and the board's LED blinks red	An error in the firmware or a loose FeatherWing. Read the serial console (Test it and read the log).

More detail (for tinkerers)

• The eyes are driven as "servos" on the PCA9685 with a pulse range of 0–6550 µs. At 50 Hz (20 ms) that tops out at about 32.8% duty, so the eyes never reach full PWM brightness. The simulator shows the same.
• The FeatherWing shares the I²C bus (board.SCL, board.SDA) with the Feather's LIS3DH; hardware.py makes one bus and gives it to both.
• hardware.py turns on board.EXTERNAL_POWER at start-up, which powers the Feather's external outputs.
• The wing pulse range is 544–2400 µs. Don't change it: it matches the servos. See Calibrate the wings.