JC Project

g5hn710m4xpdwy

Rightoh. My JuniorCert project for Metalwork is to build a model ATV. The catch is to design your own steering mechanism and wheel linkage at the front.
Instinctivly RC came into my head. I am not too sure if I am allowed to do this and will be checking with the teacher but if it is... I'v been thinking.
This is a small scale model so I am going with a Micro servo and Micro receiver
Once I figure my ways, could I hook that up to a 9v PP3 battery? (I'm wouldnt be expecting more runtime than 1-3mins)

If all that is possible with out too much fault I would try go down an ESC route, problemo is that I would need a Micro ESC But the ones that look like they should be used in a car are all $50+ Thats not quite in my budget. But then I got thinking that the motor im using is a very bog standard motor from Maplin. Nothing really RC style. I think they are called something like MM26/MM27/MM23 (If its something like that its probably one of those) So could it be driven by an ESC?
For the ESC I was looking at... Great Planes ElectriFly C-12 Micro Brushed ESC w/BEC but from the looks of it thats ment for planes and planes only.
Would I be right in assuming this?

PS: I know I would need to test all the output voltages which should be no problem.

PPS: I have included the pictorial veiw to give you the jist of what I am talking about. The battery must be mounted where "7" points too. That area under the switch (where 6 is pointing) should be fairly empty to place things. and maybe on the grate thing on the front top. Another problemo is "11"... I have to include the handle bar. I am thinking of mounting the servo on top of that and stuck down to the grate thing (8)

Hope I can share that pic...
Anywhos,
Thanks

EDIT: I'm not asking for suggestions to for how to build the steering thing a whole differnt way other than RC + Hope this isn't agaisnt some hidden rules

coolwings

That is a nice project. It should be fun. :-)

I designed and made a self design carbon fibre car for myself a couple of years ago, and it was a very satisfying thing to make and use.

Two things:

* Those aircraft speed controls you're looking at have no reverse. They are one way, and very low power too. Don't waste the money on them. They won't be much use in other stuff later (except indoors models).
Have you considered making your own mechanical (servo operated speed controller and possibly get more marks for your work?


* Those 9V cells are useless for running motors. If you open one up inside is just 3 button cells like your camera or watch uses. It can't supply enough current to move motors.
So later after testing, you will end up replacing it later with a battery that can supply more power, but by then the bigger cell won't fit into the teeny little square hole you allowed for the 9V cell. Design for 4 x AA cells as a minimum (maybe in the receiver battery box), and even better 4 x C size cells.

BFassassin

afaik part of the rules say that it has to run off a 9V batterty.
Its a nice project and should be easy enough and fun to do.

coolwings

BFassassin wrote: »

afaik part of the rules say that it has to run off a 9V batterty.....

If that is the case, check the motor and battery before starting.
A 9V square cell is capable of spinning the motor in a watch, the alarm in a clock, and not much more than that.
With a tiny motor and a huge geared reduction to a crawler speed the torque could be geared up to useful power, otherwise several cells would have to be parallelled to get serious current flowing.


Be sure to check it out. But I would be surprised if that limit is in the rules, the organisers should know the limits of such batteries, and not place their students into having to put 5 or more 9V cells in parallel to do useful work.

If the rules state 1 x 9V cell, then superlight models will be best, gear it down, and friction should be avoided like the plague to conserve energy.

BFassassin

The main point of the motor on a JC project is just to show that its capable of moving not really to run for 15-20 mins. Its strange but thats all the examiners would be looking for.

g5hn710m4xpdwy

It's a basic motor. nothing good about it. runs at either 3v or 6v depending on the one you get. It has to run off the 9v PP3 unfortunatly. Even if it jsut runs in the beginning like that I can upgrade it when I take it home and play around with it. I'll put up the full design sheet and it may answer some thoughts about it. It includes the circuit layout

Thanks for your input.

SLIM19198

Lads, stop overthinking this project!!!!

All the necessary parts are available in one of those cheapo rc cars, the likes you would find in maplin!

If you want to spend a bit more, buy an X-mod, you will get radio gear, servos, speed controller, all in one reasonably priced package!

You can even tell the examiner that it is X-mod compatible and hop-ups are available from most rc hobby shops and Ebay

coolwings

Flunked wrote: »

... It has to run off the 9v PP3 unfortunatly ...

Gear it down. Keep it light. Best of luck with it.