Wiring

The circuit is fairly straightforward and can be assembled well within an hour.

Headers (included with Trinket) may be soldered to facilitate attachment to a breadboard or proto board. Other parts may be pressed into the breadboard. Ready-made hookup wire or cut to fit wires make the connections.
These diagrams are the same for all versions of Trinket and Gemma.

The same circuit with Gemma. The LEDs share D0. D2/A1 is hooked to the junction of the photocell and a 1000 ohm (1K) resistor. If you wish to just rely on the power pack on/off switch, you can eliminate the photocell and 1K resistor.

The battery pack works well with wearables. It has a JST connector to plug directly into Gemma. It also has the on/off switch to save power when the circuit is not being used.
This guide was first published on Oct 30, 2013. It was last updated on Oct 30, 2013. This page (Wiring) was last updated on Sep 06, 2019.