This pretty simple DIY moving skeleton can make a Halloween party a bit more "scary"...
When someone comes in range, it suddenly "wakes up", lifts his arms and eyeballs glow in red!
Let it hanging in some dim light place and wait for a "victim".
- A plastic skeleton with moving joints
- Arduino UNO or, better, Nano/Mini
- 9V battery with clip cable
- 1 x ultrasonic sensor (SR04 or, better SRF05)
- 2 x mini servo motors (like common SG-90)
- 2 x red LEDs
- 1 x metal bracket
- 2 x spacers and screws
- wires, connectors, tape
I also used a prototype shield, just to make GND and +5V connections easier, and a few breadboard jumper wires and some Dupont Male/Female proto cables.
Step 1: Arduino and Servos
First of all find a proper place where you can fix your Arduino to the skeleton. I placed it behind the chest and fixed using a metal bracket from Meccano and two small screws through two spaces between ribs (see pictures). Fix the 9V battery somewhere, I used the spinal column to hide it (a bit).
Then you need to let the servos control arms. I removed shoulder junctions, then put the servo in place with its axis aligned with the junction hole. Using a small wire (I simply used a telephonic wire without plastic) fix a servo "L" shape adapter to the arm. I made two small holes on humerus to let it hold the servo adapter, then using a small screw fixed the servo to it. Then fix them to the shoulder, I used again a small piece of telephonic wire tied to shoulder and upper hole between ribs (see picture).
Step 2: Skeleton Eyes: Sensor and LEDs
Now take the ultrasonic sensor (I suggest SRF05 because cheaper SR04 are often bugged) and fit it inside the orbits: this will let your skeleton "see" if someone is near to it, and also makes the skeleton a bit more "scary" as it seems be "staring" at you... In my case I used a cutter to let the sensor properly fit orbits.
Then fix the two red LEDs next to the sensor and connect everything to Arduino following the enclosed schema.
Install the SRF05 library (file "SRF05.zip") under your "libraries" directory (or using Arduino IDE), then upload the sketch program (file "Scheletro.ino"), place your ardu-skeleton somewhere and you're ready to have a funny Halloween with your friends!