Bag O' Bones: a PIR jump-scare Halloween skull on a Pimoroni Inventor 2040 W

Bag O' Bones is 314Reactor's (Michael Darby) Halloween build, featured again this month in issue 170 of Raspberry Pi Official Magazine's Pico Halloween roundup. He bought a bag of plastic bones at a Sainsbury's and turned it into a skull that notices you, rattles and plays music. He started on a plain Raspberry Pi Pico (RP2040) and moved to a Pimoroni Inventor 2040 W, an RP2040 board with Wi-Fi that makes it easy to plug in a motor, a speaker and sensors. A PIR motion sensor sits inside one eyeball of the skull, a Pimoroni micro metal gearmotor on a LEGO axle adaptor spins an off-centre counterweight like a rumble motor so the skull shakes, and a Pimoroni speaker plays the tune. Everything else lives in a small project box under the bag. The MicroPython code (main.py in LordofBone/BagoBones) is built from Pimoroni's examples: it loops on the PIR input, and when it sees movement it starts the tune (his attempt at Toccata and Fugue in D minor), runs the motor a bit, then a bit more, and stops. It also lights one of the board's RGB LEDs for debugging, and waits again once the PIR goes quiet. His tips: the PIR needs a little time to settle after power-up before it detects reliably, drill holes so you can reach the PIR's sensitivity adjusters with a screwdriver, and keep the counterweight small, because the big one twisted the PIR wires. A bigger skull would give the electronics more room. It's a beginner build of about two hours according to the Hackster page, so there's still time before October 31. The same magazine roundup also points to Kevin McAleer's Spooky Scary Skeleton (an ultrasonic sensor and one servo on a Pico) if you'd rather 3D-print the whole prop.