Radio Control

Transmitter

I should point out that I have no experience of radio control gear at all so I was going to have to learn fast. I wasn't even sure how many channels I would need because I didn't know if I would get the flippers working. However I did need 2 for driving, 1 for the spike and 1 for ignition. I decided 6 would be the minimum to allow for all the functions I'd dreamed of.

Looking at the cost of bits and pieces I decided that the inbuilt failsafe route was the way to go as starting out with a PCM set would be more cost effective than changing over after I'd had trouble with PPM. However the many PPM vs PCM arguments on the various forums was causing me doubt. It was then I came across the Multiplex equipment recommended by Andy of the SMIDSY team. Being PPM it doesn't have the jerky weak signal response of the PPM gear but it does have inbuilt failsafes with Multiplex's own IPD system. I also liked the fact that the manufacturer actually encourages you to take the back off to modify switches etc!

SMIDSY had real battle experience and they swear by this stuff. The fact that the importer Flair Products was less than three miles from my house didn't help in obtaining the gear at all....
I finally chose the Multiplex Cockpit MM which has 7 flexible channels which can be plugged or unplugged at will and the controls changed from switches to pots etc. as you choose. The simple construction is due to the superb selectable menu system which allows a whole range of inbuilt mixers, trims or non linear outputs to be selected at will.

The inbuilt failsafes can be programmed for every channel in any position. (usually stop for a robot).
After burning out the weapon relay in Cardiff I fitted a 3.5mm jack plug to one channel and had a hand held 'plug in' weapon controller for 2 man operation. The switch remained in situ for one man operation should that be necessary.

Some of the downsides of using Multiplex gear should also be pointed out.

1) 40MHz gear is hard to come by. I finally tracked it down at King Cobra Racing.

2) It uses a 7.2v transmitter battery. No problem if you have a charger but why?

3) It doesn't work the Delbots interface yet.... wait for MK2

Receiver

The receiver used is the basis single conversion IPD one. It is powered by a standard four cell battery. This receiver has the necessary on board electronics to bring all the channels back to the pre-programmed failsafe position should the robot go out of range etc.
One thing no failsafe can do though is return a servo to 'off' if the receiver battery wire gets cut. This is where an electronic interface wins over servos. Whilst this isn't a Robot Wars requirement it could be dangerous. I achieved a failsafe under these circumstances by using an electronic ignition switch from Ken Hewitt. This switch doesn't fail safe when the radio goes down but it does if the battery is cut, so combining the IPD failsafe and the R/C switch allowed total failsafe protection.
Programming the failsafe is easy, put the controls where you want them, fit a small link plug (provided) and switch on for 10 seconds, done.
The aerial provided, green for 40Mhz was slotted inside a 10mm plastic pipe which sat inside the plastic barrel forming Ruf Ruf Dougal's top armour.

Weapon Controller	IPD Receiver & Aerial