For Halloween, I decided to make a robot project to entertain myself and the children. The idea was to make a radio control robot that would transmit both audio and video a vehicle platform. A NTSC camera with IR illuminator is used to capture video of my head. To keep my hands free for controlling the vehicle, a body mount (remember the Blair witch project?) was made to keep the camera on my head. My head and voice is then transmitted on the UHF band (ch19) to a horizontally mounted LCD tv. The TV projects upward to a 45 degree piece of plexiglass that generates a seemingly holographic floating head!
Video can also come from a dvd player for non-live use. Audio/mic are mixed so "Wierd Science" back ground music can be played while I talk to unsuspecting trick-or-treaters. The base platform is a shop-rider electric wheelchair
that I picked up on eBay for $60, It needed 24V scooter battery system and a motor controller (both picked up on eBay as well).
Next ,I needed a quality RF radio. I went spread spectrum DX6 as it has fail-safe throttle down indication that I use to stop the robot if loss of communication happens - safety is paramount with a 100lb vehicle near kids!
Next, I used an AVR to convert the RC pulse train into a MOTOR control PWM pulse train that is then low-passed and injected into the normal joystick pot controll interface of the electric wheel chair. All mathmatical mixing and limiting is handled within the AVR. I used BASCOM AVR and the whole thing is about 100 lines of code.
The frame of the ghost was made from Home Depot rebar. I used a mig welder from Harbor Freight. The rib cage is also rebar. Wall-mart Christmas tree lights wrapped in white hockey cloth tape adorn the ribs and the arm structure. Cheese cloth provides the tattered clothing. Party City had a hollow rubber heart. By placing White blinking Christmas lights in it, it give the illusion that it is beating while suspended in the rib cage. The whole 110V system for the lighting and the TV is run from a 400W Kragen power inverter and has a separate 12V battery system.
The control center has a black-back mask to prevent stray light from behind me getting into the captured face shot. On the right is the DVD/mp3 player. On the left is a monitor that shows what is being transmitted (ir cam or dvd). The audio mixer is on top. The UHF transmitter is in front - I mounted a tune knob for convenience on the front to keep it "locked in". I had to hack the video sender to run off of the 12V NIMH packs that sit below the black masking plate. They provide a mechanical counter-balance that reduces the fatigue of walking around with the over-the-shoulder control center. Black hockey tape wraps wire and sponge material for comfort.
Watch it in action by following this youtube link: http://www.youtube.com/watch?v=vLolapeeXKo
I hope you like this project. I thought of it on October 1, I have not had much sleep since then.