WHEN: Most Friday evenings. TIME: 7:15pm.

15 June 2009

Costa's breadboard controller - part 2 final

Rather than a nuts and bolts view of the hook up wiring, I have rather re-posted the layout schematic with a note that the transistor view on the layout is the bottom of the transistor! Seem obvious but I had it reversed on Gordon's unit that I could never get to function. Most of the wiring tucks away in the unit and the drawing actually does a better job of showing the hook up than I could.

Thanks to the Ecurie guys for slotting me in to a race after a late arrival on Friday night - the controller was truly tested in action from first press and worked fine with a useful third overall, despite the rusty driver.

The pictures illustrate the neat and uncluttered final product. I have also included a cut out of the Gordon economy handle to illustrate how the black lead is bolted to both sides of the transistor top with terminals, one for the contact to the trigger and the other black lead to jack plug. The orange thing is a resettable fuse and well worth the extra precaution if you lend out your controller from time to time. The circuit theory borrowed from the excellent Christ Frost and Le Mans slot car web sites, with the neat artwork off this interesting web site:

The sprung button in the MRRC controller is a boon right out the box but, in this Parma Turbo project, I simply bent the end of the wiper arm and bolted on an old brush hood unit off an old can style motor (16D or C Can units fine) - the motor brush being the smoothest approach I have come across for cheapie homebrew units.

My unit will have the two pots facing out rather than in as I found my method of holding had me unintentially winding the sensitivity to zero through the race (not an issue for most other folks). That's it in this series, there may be a further breadboard approach to the interesting MRRC controller, time will tell. In the absence of the metal turbo frame, a small lightweight heat sink and fan (The dinky little Hobbywing RC unit for R85) will be fitted, along with reverting to the Tip36c and a 30 ohm total wiper board to explore the potential of other folk using the existing resistor as a wiper board.

Any net readers are welcome to email the team to find out the component sources etc, although most of mine were from Mantech, locally.

10 June 2009

Costa's breadboard controller - part 1

Some gentle persistence from Chairman Costa got me to scratch out the previous start of an "easy to follow Assembly" controller, commissioned by him so long ago. This is the Parma Turbo and it is hoped to do same with the new good value MRRC controller. Thought it worth dealing with the basics without the clutter of hook up wire, first. Of course this is where the steam ran out before so hopefully this motivates the part 2 for final completion. Click on the pic and study the large version closely before reading on. Costa's requirements in bold:

1. Minimum butchering of the controller case. With the above approach there is virtually no dremel cutting of the a Parma Turbo case, although a standard case would have to opened at the top ala the Parma Turbo space for the frame. Three pimples are removed from inside the case to clear the transistor and new spring position. Easy to spot when closing the case together.

2. Simple layout to follow. The brake pot is just above the brake stop and the sensitivity pot is a similar short distance away from the full throttle hook up, requiring very little hook up wire and a circuit layout which can be followed by someone with no electronics knowledge at all. Obviously all the long spiky arms will be cut off the potentiometers after the hook up wiring is complete, so there will be no pricking of precious fingers.
3. Minimum parts count. The transistor uses the Turbo frame as a very efficient heat sink. The frame kindly already provides the necessary holes, which only need a some extra opening up to prevent shorting of the two hook up legs, which are bent over to clear the case. A cheapie transistor insulation kit is a must to prevent electrical shorting against the frame.

4. Minimum drilling. There only two extra holes drilled in to the frame to hold both the fibre potentiometer board and the wiper board. The resistors are first soldered in the back of the wiper board whilst being bent flat. That means the board can be located very low down with no fouling of the upper case by the wiper arm.

5. Relocation of the trigger spring (not specified but essential). This is very important to ensure effective returning back to the brake stop. The frame also kindly already provides another hole in to which a new spring holding point bolt is locked. The original spring locating arm will be bent over to hold the main cables in place. Costa's Turbo controller kit had the best spring supplied that I have ever seen in a Parma controller, by the way - way better than the old barbed wire Turbo springs and saves pinching out of old Economy controllers.
6. Minimum manufacture of parts. The pre-made wiper board is available locally and online and is well worth it to simplify the project. Thus the only element of home manufacture is the small piece of board to hold the two potentiometers and bolt to the controller frame at the two points mentioned. This can really just be eyeballed off with the pots themselves before drilling and cutting the board.
That's it! Roll on part two wiper arm and hook up.

03 June 2009

Scouts Race Meeting - 2009/05/30

In what has become an annual event, the Club hosted the Scouts again on Saturday 30 May. This motivated some of the members to undertake a much needed clean up of the premises beforehand. Thanks to Mike, Costa, Tony, Vic and Phil for the hard work put in prior to the event. Vic did a sterling job cutting the grass while the others scrubbed, swept and vacuumed inside. The less said about Phil almost flooding the Club the better!

Unfortunately Neil Robinson couldn't make it due to work commitments but his brother Gavin was there to help us organise the event. With 17 Drivers, numbers were down on last year but enthusiasm and enjoyment were no less!

Erlo had done a fantastic job on the cars which have taken somewhat of a hammering in the last few months. Not content to simply service and clean them, the cars were re-sprayed and sported new decals. Apart from a few minor problems, the cars performed well throughout.
Practice started at 3pm, followed by two qualifying rounds and then the finals. With Costa on Race Control and Mike instructing the drivers and keeping order, the event ran like clockwork and ended at 6:30pm. A great deal of fun was had by all, and we look forward to hosting the Scouts again next year.