question for the electrical engineers
 

i'm thinking way way in advance here.... our prototype for our design project next year needs to be able to be powered on and off, and have speed adjustments carried out remotely (by remote control ;)). [project is top secret, but anyway...]

so, can anyone give me any pointers to sites and things that would help in designing a remote control system? due to the nature of the product, IR would not be suitable, would need to be a RF system with as small an aerial as possible. i'm thinking of getting a small RC car and cannibalising it for parts to start with, but if anyone could give me any pointers i would be grateful.

basically, a speed of between 0 and 5mph needs to be adjusted remotely... i'm not exactly the best in the world at electronics (despite A* gcse electronics) so pointers would be helpful :)

Re: question for the electrical engineers
 

My mate's had one hell of a time with RF stuff at uni. It's like witchcraft.

i've pm'd you.

Re: question for the electrical engineers
 

have a look on here for the RF remote and receiver

http://www.interq.or.jp/japan/se-inoue/e_pic6_8.htm

Re: question for the electrical engineers
 

Sounds like you'll need an ESC (Electronic Speed Controller) that you'll find in Electric remote control cars. These vary in price but you can probably pick one up on Ebay for a reasonable price.

Re: question for the electrical engineers
 

Re: question for the electrical engineers
 

If its for near exact control (inc Torque) try "electronize" products

www.electronize.co.uk

Microprocessor speed controllers..

Selectable mode processor system, high, low or variable frequency control.
DSP for smooth operation
can run motors up to 30 amp DC
90 Amp short term stall rating (short time)
low loss power MOSFET switching
screwdriver speed adjustment range
runs from 6 to 24V DC supply
standard RX RC input no servos required.

can be bought in kit form or pre built (kit is cheaper) and have various types available from £20.45 to £41.55.

I use an FR30HX (specs above) which gives near perfect speed control.

Re: question for the electrical engineers
 

You need an anorak. There used to be a model shop in Crossgates that had them. You'd go in and they'd be in a huddle talking about the latest toy. Struck me as very sad, but I imagine they'd have the answers to all your questions and, in that anorak way, get a kick out of helping. So find the domain of the anoraks near you.

Re: question for the electrical engineers
 

what's anoraky about helping people? :confused:

Re: question for the electrical engineers
 

Clearly, for some people, helping out isn't normal. :erm:

I'd personally buy a really cheap remote control car, and cannibalise it. Two reasons; a) it's cheap enough to do, b) my theory is the RF circuits on cheap cars would be less sophisticated than on others. :)

Re: question for the electrical engineers
 

But on the same basis may not provide the right kit to do the task ...
And depending on how much you want to spend an ESC will cost anything from £20 but can go up above £200!!!
If you can keep it in good nick, you'll always sell it on Ebay...

O and they is nothing "Anorak" about helping people with model car racing, it gets very serious at times especially when people are spending a grand on a new car to race! - As Thomas would say "Helping others is fun and it doeesn't hurt a bit"

Re: question for the electrical engineers
 

ok just so everyone knows, i'm not building a model car.... it's for a component for my mech eng group project :)

has to be quiet cos we are treading new ground with a couple of areas that haven't yet been patented :angel:

Re: question for the electrical engineers
 

Sheeesh - sensitive lot are these anoraks :D I love anoraks :hugs: Just in case there are any gun anoraks out there :erm:

What I meant was that if someone, say, fetched in old model X whatever that had seen many better days, your average anorak would be excited at the prospect of putting it back together. Likewise any unusual challenge such as that offered by Dave.


:Peaceman:

Re: question for the electrical engineers
 

You need to be able to adjust a speed controller with RF?

As said, go down to your local RC shop & look in there, chat to the owner.
It sound like they would be best suited to help you.

Of course there are kits available.

Re: question for the electrical engineers
 

the chances are he's got to build it entirely from scratch, including programming it. making his own rf kit, just buying the needed ICs.

Re: question for the electrical engineers
 

dredging up a semi old thread but anyway. ignoring the remote control bit for the moment, a circuit similar to the one at http://www.electronics-lab.com/proje...012/index.html is going to be used for the motor control circuit (it seems to do the job fairly simply).

now anyway it's been a long time since i did gcse electronics, can anyone give me a list of the components in this circuit? it's not gonna be built on PCB incidentally, just breadboard for now :) but still, like what types of relay would i need and so on... (oh, and 9v battery instead of 12v) :)

Re: question for the electrical engineers
 

Hmm, hazarding a guess...

Looking at Maplins, 9V relays are quite hard to come by.

Maybe if you cannot use 12v then you will have to stick to 5v ones & stick 6 off 1A general purpose diodes (1N4002 etc) in the top +vline, the bit between junctions directly above the common pins of A2 & B1 relay contacts.
This would drop the relay control side to 5v while leaving 9v for the motor side.

The relays can then be like these or may have to be bigger depending upon the current drain of the motors in the R/C car.

The switches appear to be simple single pole "push to make" ones like these.

However, relays can use a lot of current, be quite big & expensive.
A circuit that uses transitors/FET's may be of better use.
This one that is from in the Cybot project ( currently in the loft) may be better. Adding switches or better still PIC control would be required.

Try seaching for robot control sites for further ideas.
here and here are other examples.

Re: question for the electrical engineers
 

they 9v thing is not particularly essential, its just for the test board as 9v square batteries are easier to come by than a 12v power supply ;)


i had a look at H-bridge drives, but my simple electrical nollidge gets a bit confused :)

remember, this is just a prototype that is gona be built on stripboard ;)

Re: question for the electrical engineers
 

The "stock" RC solution (to a simple reversing issue) would be to use a servo to tickle a couple of microswitches - not as fast as a full electronic solution.

I believe Maplin do RC kits

Re: question for the electrical engineers
 

well i have got 45cm of stripboard, several million components and my not so trusty JML coldheat, we will see what i can bodge together from this circuit ;)

it's not for a remote controlled car btw...