Connecting The External Components - Arduino MNC6 Construction Manual

AUX "Auxiliary output". The clock is capable of driving additional APA106 elements
OUT in addition to the 6 on-board individually addressable tube back lights, as well
as an external sounder if you want to use an alarm.
Note that the "LED Out2 and "SND" functions require a code change to
implement them, the standard software does not support them.
GND: The "ground". One lead of the button and one lead of the LDR are
connected to this.
LED: If you want to drive additional APA106 LEDs, you can daisy chain them
on this output.
SND: This is an open collector output to drive a Piezo sounder.
V+: Auxiliary output supplying the input voltage, used for driving the Piezo
sounder
PIR: An additional input for the PIR.
5V: Regulated 5V output to drive auxiliary circuitry. This output can only
provide 100mA, so please do not try to run extensive circuitry from it.

Connecting the external components

To connect the external components (Light dependent resistor, motion sensor), please refer to
the image below:
The buttons BTN1 and BTN2 are in parallel with the on-board buttons. You only need to connect
them if you want to have alternative buttons on the outside of your case.
Here is a detail of the edge connector:
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