R2D2 PROJECT USING PICAXE MICROCONTROLLER FOR ESSENTIAL FUNCTIONS
BRIEF: To construct an R2D2 robot with minimal resources. Movement restricted to Dome only. Robot to detect and respond by moving it's dome and flashing its holoprojector using a PIR detector. This unit will not run away - too heavy!
testing the PIR detector
When the PIR activates, it sends a signal to the PICAXE, On detection, the PICAXE outputs a 5 volt signal which connects power to an LED lamp via a transistor operated relay. It's all nuts and bolts really.
I was fortunate to receive an aluminium dome for R2 from another person who had completed his unit. An acrylic plastic dome from Cambrian Plastics at 69 Henderson Valley road would be equally as good but will set you back about $50. If you look carefully at many reproductions of R2D2 you will notice that some domes are slightly egg shaped (the correct models) and others like mine are pure hemispheres. It really doesn't matter which are used as the unit is still easily identifiable as R2D2. In the real droid made for George Lucas, there are two domes, an inner dome inside the outer one. The motor is from Jaycar Electronics in New Lynn and although designed for 12 volt operation, runs nice and slow on a 6 volt SLA (sealed lead acid) battery. It also makes the same noise that R2 makes in the first film, though it sounds like a bucket of bolts on the Samsung camera.
The rights to Star Wars became somewhat complicated lately when Lucas and 20th Century Fox sold them to the Walt Disney Film studios. Except however, Star Wars IV, A New Hope which Fox has retained indefinitely. To cut a long story short the copyright to all the props of the film are strictly monitored including R2D2. This means that the unit I am building cannot be sold.
Testing the DC Motor - it sounds noisy but it isn't really.
Andrew Ainsworth (industrial designer from Ealing Art school) in England discovered how serious Lucasfilm could get when he started making Storm trooper helmets and other parts and selling them on the market. He was taken to court. However, Ainsworth was the original artist back in 1976 who manufactured the helmets for the first Star Wars film, (before it became known as Episode IV, a New Hope) based on the red clay sculptured models by colleague Nick Pemberton). Ainsworth had kept the original molds and decided to sell the helmets to help pay for his kids school fees. He'd been doing this for years before Lucasfilm found out. He then felt the full force as Lucasfilm sued him for 9 million dollars which reduced to $135000 after appealing through the High Court and Supreme High Court in London. However, Ainsworth thought it unwise to try and fight George in the USA on his home soil. So although he can make the masks in the UK and Europe, the USA market is now off limits.
In the real R2 the motor is mounted vertically inside the body but I found this method easier to use because of the design of the lazy susan bearing I bought. The rotation of the dome in the video above is done using a switch which is ok for testing but not suitable for the end product. I want the unit to detect movement and respond using a microcontroller (PICAXE CHIP) in this case. The interface between the 'chip' and the motor consists of two Omron relays. Power is connected to the red wires and the black wires provide an earth return. In the off condition the relays are not activated and no power is applied to the motor.
If a voltage is applied from the chip to one of the green wires the corresponding relay will activate and the motor will rotate in one direction. If the other green wire is activated, the motor will rotate in the reverse direction. I intend to rotate the dome 360 degrees, stop, move left and then right before stopping. I will need to centralise the dome so that it faces the front when it stops. After that I guess the dome needs to randomly bobble left or right to seem more realistic. I would also like the disc player to operate and play R2 sounds. This can be done manually by pushing the front buttons but I think I'll have to hack the hardware behind its cover and control that with the microcontroller.
The PICAX Microcontroller from Revolution Education