11

FORGE

Left

Bolted connections

using washers and

2.5 mm bolts

OTHER IDEAS

• Paint your skull in candy skull style for a ‘Day of
  the Dead’ look.


• Use PWM to make the eyes fade up and down,
  rather than flash.


• Use servos to make your skull move.


• Swap out the Gemma with a Circuit Playground
  Express board, and add some audio effects to
  your project.

On the Gemma

M0, like many

microcontroller

boards, the pins are

shared and can do

different tasks.

This can be a useful technique to simplify the code QUICK TIP
you write later.

touch_pad = board.A0

touch = touchio.TouchIn(touch_pad)

led1 = DigitalInOut(board.D0)

led1.direction = Direction.OUTPUT

led2 = DigitalInOut(board.D2)

led2.direction = Direction.OUTPUT

The pins need to be configured before we can
use them. The A0 pin is configured for touch, D0
and D2 are configured as digital outputs. Note how
Direction and DigitalInOut don’t need a prefix as we
imported those specifically above.

def detected():

for i in range(3):

led1.value = True

led2.value = True

time.sleep(0.5)

led1.value = False

led2.value = False

time.sleep(0.2)

This code defines a function we can call when the
skull is triggered. It flashes the LEDs three times,
with a short delay between each flash.

detected()

while true:

if touch.value:

detected()

time.sleep(0.05)

To check that the lights are working, the code calls

the detected function when the Gemma first powers.

The while statement creates a loop that will keep

running until the power is turned off. It checks the

touch sensor to see if it has been touched. If it has,

then the code calls the function defined earlier to

flash the lights.

Upload the code to the Gemma and remove

the USB connector. Fit the batteries to the battery

pack, and plug into the Gemma. Test everything is

working, then fit the electronics into the back of the

skull. Add some treasure to the bowl, e.g. sweets.

Your monkey skull bowl is now ready for use.