I got the batteries, two 7.2V NiMH 5100mAh racing packs, a 30A speed controller for the weapon, which is intended to control the motor in large scale remote control cars, and a 31'000 RPM electric motor, for driving large remote control cars, from Antics. [Google it and its the first on the list]
I also got some unassembled packs battery connecters so that I could make the system easy to disassemble, a 20 tooth drive gear for the electric motor and a battery charger. On the way out I also popped into a lighting shop and got a rack of 30A connecting blocks. I had discovered the other day that I could not wire 2 20A cables into a single 20A block which meant that it was impossible to wire up the system given the number of splits I needed to do to get the power to the right places.
With all the parts I needed I went into uni and began wiring everything up. It took about 4 hours to tinn the ends of all the high amp cables, solder them to the appropriate connecting links and blocks and make sure that all the polarities were right. There was alos the fiddly time of trying to get a 30A gauge cable into the socket on the sabertooth, it was only big enough for about 2/3rds of the wire so I had to thin it there to get the cables in.
After binding the transmitter and receiver I wired up all the motors and the speed controller to the batteries and everything started jumping. Despite the transmitter with all its switches in the safe position the motors kept spinning at random back and forth. The drive motor for the weapon was linked to the throttle on the receiver and immediately went to full power scaring the hell out of me. Well more than full power give it was meant to run at 32000 rpm at 7.2v but I was giving it twice that and as a result twice the speed. It makes a scary noise!
After turing everything off and taking a minute to chill out it turned out that the throttle safe was not a default on the transmitter explaining why the weapon motor had gone mad. But despite fiddling with the trim for the drive motors I could not stop them spinning totally, even after several rebinds.
Despite these problems, and the annoying fact that my supposedly infallible 2.4Ghz system was not as it claimed interference free, I had everything under some kind of control. With the safe switched on the weapon motor only started when I went past half way on the throttle and only went to full speed when I made it. The drive motor also did what they were supposed to as well, changing direction and turing at the correct speeds. There was a slight hiccup when I thought the the motors were drawing to much power for the sabertooth to cope with but it was only when it was doing it silly twitching thing and changing directions at full speed when it spiked. The first of which could be rectified totally and the other was just part of the system.
There was an even better moment when I moved the system onto the floor to take photos. The motors stopped twitching as much, down to almost nothing. It seemed that my infallible transmitter was being flummoxed by something inside he computers. Perhaps there dual 2.4Ghz processors, I don't know.
I will hopefully be uploading a video showing in detail the system and how everything is wired so that anyone else doing this wont have all the problems I had.
Next up is the chassis and attaching the wheels to the motors, which you would have thought would be simple but, no. The box section has been cut to length but due to the fact that I have done another redesign of the robots layout and the weapon's system it wont we welded before I have to go home.
The project may stall for the summer due to a lack of any tools or equipment or money but I should make some progress in various areas.
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