Some motor help please

[corytran]

Hello I have this motor...and it is connected to an RF board that turns it on by pressing a button on a controller and off by releasing that button.

The problem I am having is that I can only make it turn one way....and I need it to turn the other way.

My remote has 4 channels so I want one button to turn it one way and another button to turn it the other way...

So I thought all i had to do was wire 2 circuits.  One connecting one channel (button a) to make it spin one way and the other connecting another channel to make it spin the other way.  But when I did it like that it seemed to short out both circuits and all i get are sparks...

I wish I could upload a picture to explain what I mean...maybe i can draw a diagram...

Please help me!!!  My friends say i'm a girl so i can never do this....so help me prove them wrong please!!

[corytran]

Here is something I Drew...kinda basic but you get the idea...(hopefully hehe)

obviously red is positive and black is negative

[corytran]

oops sorry wrong picture...

[corytran]

Ok ok...so I think i messed it up the first time I did it...must have wired it wrong...

BUT!!!!

This time i followed my diagram and it kind of worked....it started running...but not when i press the button....and if i press a button to try to turn it the other way...it did....but then smoke started coming out of the motor.....what does that mean?!?!?

please help me!!!

[Fredrik Andersson]

I guess what you need is a H-bridge.

However, we should sort out what happened here first. When no button is pressed, you have a closed circuit that goes through the ground (the outer black wire on your diagram), through the motor and then through the outer red wire, thus making the motor spin. When a button is pressed, all you should get is a short circuit (and eventually sparkles).

Now that i think of it, it may be to complicated with a H-bridge for this, though you could try because you'll probably learn a lot from it. Here is a link to it: http://www.societyofrobots.com/schematics_h-bridgedes.shtml

The easiest approach here would be using two batteries, connected parallel to the motor but with opposite directions and with a button wired into each of them. This way you'll create two separated circuits. You could still create a short circuit through pressing both buttons, because it will make the batteries connect serially.

Good luck, and prove your friend they are really wrong

[Admin]

As Fred said, you just need an H-bridge . . .

I can picture in my mind your wiring, and yea, its definitely shorting.

So with the H-bridge, you can use four regular on/off mechanical switches, or do it with electronics using four mosfets.

And don't feel too bad, my first attempt at an H-Bridge resulted in me getting painfully burned . . . so consider yourself lucky with pretty sparks

Or if you are willing to spend a few bucks, you can buy what is called a motor driver or ESC. There are a few that can hook directly up to a receiver so that you can remote control DC motors:
http://www.societyofrobots.com/robot_parts_list_electronics.shtml

which one are you in the pic?

[Fredrik Andersson]

She doesn't have to use an H-bridge, it works well with the easier approach as well. It may be better to go with the H-bridge though, if you perhaps will interface it with something else than buttons.

Heres a quick diagram of what i meant:

[Admin]

good point . . . I need to read posts more carefully . . .

[corytran]

So I can't use an H-Bridge?  I really don't want to use two batteries...cuz one is already so big and heavy...

Is there another way to do it?

You know my RF board has extra "holes" in them that i dont know what they do...maybe you guys know?


I'll draw u guys a diagram of what it looks like...maybe u can help me out....


Thanks alot for all the info guys. I'm really learning alot here.

[Admin]

I noticed this was your other post:
http://www.societyofrobots.com/robotforum/index.php?topic=2213.0

What is your budget?

Can you post links to datasheets to the parts you already have?

[Fredrik Andersson]

Oh, i should probably also read posts more carefully.

So the buttons isn't directly in the circuit. The circuit is connected to a RF board... Then you should really go for the H-bridge.

[corytran]

http://www.quasarelectronics.com/3180.htm

This is something like I have....the only difference between this and the one I have is that mine doesn't have this feature: "Each channel has a Reset input for connection to a limit switch (not supplied). When used in Toggle mode, the relay with automatically turn off when the limit switch is closed."

I thought I had the perfect circuit drawn out...but there is something wrong with my RF relay switch board...
let me show you guys a picture of what i had in mind...

Obvioiusly red is neg and black is pos....green is either pos or neg depending if the switch is on or off.

So this circuit looks perfect right?  Only problem i have is that I can only turn one switch on at a time....do you guys know a way to turn on 2 or 3 at a time?

[Admin]

Obvioiusly red is neg and black is pos

You mean red is positive and black is ground?

Your schematic will work . . .

Hmmmm so if it only lets you do one relay at a time, this might be a problem . . . you could wire the relay control pins together, but this will probably damage the circuitry so it won't be undoable . . .

I got a new idea . . . do you have a second motor? What you can do is have two motors attached to the lid of the box - one of them is only wired to open the box, while the other is only wired to close the box. Its almost like your muscles, because muscle can only contract. Doing it this way will only require 2 relays.

[corytran]

2 motors?!!?! WOW THAT'S  A REALLY GOOD IDEA.  THANKS

[Ro-Bot-X]

You only need 2 DPDT relays...
One channel of your RF board triggers one relay. The relay pins are wired like this: the middle pins go to the motor and the NO pins go to the battery. The second channel triggers the second relay, with the motor pins connected like on the first relay, but the battery leads are reversed.

Make sure you don't press both buttons at the same time on the remote!!! You will short the batteries!
       

[Admin]

hmmmm I feel dumb now, forgot that relays can be DPDT . . . listen to Ro-Bot-X . . .

I saw 6 connections and 4 relays (instead of 8 and 4) so it just didnt compute in my head . . .

[corytran]

You only need 2 DPDT relays...
One channel of your RF board triggers one relay. The relay pins are wired like this: the middle pins go to the motor and the NO pins go to the battery. The second channel triggers the second relay, with the motor pins connected like on the first relay, but the battery leads are reversed.

Make sure you don't press both buttons at the same time on the remote!!! You will short the batteries!
       

omg i am soooooooooooo stupid....i can't believe i didnt think about that....well i actually i did but the way i wired it the motor kept spinning because it completed the circuit through the NC connections...LOL but all i have to do is flip it so that both the NC's are positive or negative.

I'M GONNA GO TRY THIS RIGHT NOW!!! THANKS!!!