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daniel_123
05-11-2008, 12:54 PM
Hi
i want to use a servo-phidget (last picture) with a niKKo car
but there are several problems
i can plug the 2 wires of the servo phidget (orange-red) to others wires on the car, the wheels will turn to the max ot the motor will accelerate to max also, i can't switch on/off with the servo methods (in Java or C#)
this is probably due to the car motor, so i can either change the car motor or
as somone in phidgets.com told me get a 1064 PhidgetMotorControl HC but im not sure it will work though

Thanks for the help


http://www.phidgets.com/phpBB2/viewtopic.php?t=2186

http://img131.imageshack.us/img131/3200/image002iv0.jpg

http://img329.imageshack.us/img329/1320/image001sj1.jpg (http://imageshack.us)

Adrenalynn
05-11-2008, 02:51 PM
Yup! That's the problem! Your car isn't driven by servos - it's driven by motors. Two different animals.

You're fortunate you haven't burned-up your servo controller yet, the motors must be small, but you can be assured you're on the way to doing so...

You're needing a motor controller, and a motor controller sized appropriately to your motors.

Welcome to the TRC, btw!

[you didn't mention what Nikko car specifically, or even better, what size motors, so we can't advise on size or type of motor controller, but the upshot is that you did get solid advice on the phidget forums]

daniel_123
05-12-2008, 07:19 AM
Thanks

yes sometimes the servo smells burnt after i used it! i wondered why

there is a little white motor for direction and on the other side of the car another motor for propulsion
the battery for the car is 6V so i guess the motors use this voltage

So my only solution is getting a motor controller?

Thanks again
Sincerely

Adrenalynn
05-12-2008, 09:47 AM
Can you take pictures of the motors? It's the directional motor that has me concerned. The drive motor - I'd feel good about pointing to something like the small banebots and saying "that one". want to make sure, though, that we know what we're getting into with the steering.

If they're both similar motors, you could also use a two channel controller like the sabertooth and save a few dollars over buying two separate controllers.

darkback2
05-12-2008, 01:35 PM
I'm not sure you should count out a phidgetservo controller just yet. I would imagine the car has some sort of ESP controlling the speed of the drive motor. If you could trace that back you may be able to find a way to bypass the reciever output and use your servo controller. THough it would be a lot easier to just hook the motor up to a motor controller directly.

daniel_123
05-12-2008, 03:24 PM
here is the motor for direction

http://img106.imageshack.us/img106/5429/image001ke4.jpg

better photo : http://img376.imageshack.us/img376/7229/image001iu3.jpg

Adrenalynn
05-12-2008, 03:43 PM
I just don't think trying to send PWM into their electronics will have a big payoff. You could separate out their receiver circuit and tie in on the back side, hypothetically. But likely that's all going to be SMT. If you already had the skills to reverse engineer their SMD multilayer board, your questions would look different. ;)

This car is differential/slipskid right? (The wheels don't turn side-side in the front or the back like steering wheels, right?) It can turn in its own radius?

daniel_123
05-12-2008, 05:26 PM
sorry I didnt understand all u said, i don't know a lot in electronics
the direction motor is very simple only 3 positions straight, right and left
when i plug the servo wires on the blue and yellow wires for directions, it turns right (or left) .
unfortunately there is no way to control it after, with the phidget methods and interface

Adrenalynn
05-12-2008, 05:43 PM
Do the front wheels turn left and right like a real car's steering, or do both the front and back wheels on one side go to cause the turn?

Alex
05-12-2008, 08:25 PM
Do you have a motor controller that your Phidget Servo Controller is connected to? If so, many motor controllers are/can be driven by PWM signals generated by a servo controller.

daniel_123
05-12-2008, 08:26 PM
sorry yes front wheels turns like for a real car

Adrenalynn
05-12-2008, 08:44 PM
No - he's trying to drive the motors with a servo controller...

Adrenalynn
05-12-2008, 08:47 PM
I'm wondering if it's a servo on the turning mechanism and motor for forward/backward.

Alex
05-12-2008, 09:02 PM
... Maybe I'm totally missing something but isn't this a speed controller:


http://img131.imageshack.us/img131/3200/image002iv0.jpg

BTW, yes, I'm tired and probably shouldn't be posting right now:p

Adrenalynn
05-12-2008, 09:19 PM
Yup! It's also a receiver, I believe, from another picture. Looks like a monolith. He's wanting, as I read it, to take control via computer.

Adrenalynn
05-12-2008, 09:21 PM
I see what you're getting at. Similar to a post above - he's going to need to break-off that receiver's output to tap into the motor controller directly. I agree that's possible, but maybe not probable. :)

Cutting the motor wires and wirenutting a banebots motor controller on there sure sounds more fun. [Says the chick that is currently building her own microprocessor controlled NiMH/Li* charger from scratch as she types this...]

daniel_123
05-13-2008, 06:55 AM
yes you guessed right I want to control the car via computer
http://img131.imageshack.us/img131/3200/image002iv0.jpg
on this picture, I plugged the servo controller on the blue and yellow wires to make wheels turn, it turns to the max no way to control it
I wonder , if I plug the servo directly on the direction motor, bypassing the circuit, it may work fine

daniel_123
05-14-2008, 11:07 AM
Hi again

http://www.trossenrobotics.com/store/p/5104-Sabertooth-dual-5A-motor-driver-for-R-C.aspx
Do you think this interface linked with the servo-phidget will work?

Adrenalynn
05-14-2008, 11:48 AM
I run the larger version of that with both the servo-phidget and with the SSC-32, in fact, I have one running on the SSC-32 even as we speak. Your motors are small, so I'd have to imagine it'd be fine. The Sabertooth is *very* well protected against overcurrent/overvoltage/undervoltage/heat, so even if it didn't it'd be very difficult to "blow up" - as long as you observe the supply voltage (battery) polarity...

I'm a big fan of the Sabertooth, outside of operator error in programming it with the SSC-32 and with the phidget, it's been rock-solid stable from day one, even getting beaten for ten hours at a shot. And it didn't fail in competition for us - always a good sign. ;)

The banebots motor controllers are also nice, though.

The non-RC version of the Sabertooth can be controlled directly from serial without the phidgets in the way - but you don't get all the nice libraries and sample code.

daniel_123
05-21-2008, 05:45 AM
I run the larger version of that with both the servo-phidget and with the SSC-32, in fact, I have one running on the SSC-32 even as we speak. Your motors are small, so I'd have to imagine it'd be fine. The Sabertooth is *very* well protected against overcurrent/overvoltage/undervoltage/heat, so even if it didn't it'd be very difficult to "blow up" - as long as you observe the supply voltage (battery) polarity...

I'm a big fan of the Sabertooth, outside of operator error in programming it with the SSC-32 and with the phidget, it's been rock-solid stable from day one, even getting beaten for ten hours at a shot. And it didn't fail in competition for us - always a good sign. ;)

The banebots motor controllers are also nice, though.

The non-RC version of the Sabertooth can be controlled directly from serial without the phidgets in the way - but you don't get all the nice libraries and sample code.
thanks for your help

the sabertooth is a little expensive, I had an other solution maybe by buying other servo-actionnors compatible, or the motor-controllor-phidget but also expensive
I think sabertooth is the best solution, it works for you
could you send me pictures of how you plug all that please?

and thanks again

Adrenalynn
05-21-2008, 12:34 PM
Let me cut some zipties and I'll try to take some sensible photos. These things always seem to turn into spaghetti for me. ;)

Adrenalynn
05-21-2008, 01:09 PM
See if this helps?