servo motor with windshield wiper engine

[pantxe]

Hi everibody,

I'm buiding a rc car with a chainsaw engine and my my problem is that due the weight of the car(30kg) I need a high torque servo for the steering. I have almost no idea about electronic but I've been thinking about the idea of building a servo using a wiper engine. For that task I have found this controller on the net: victor 888 motor controller altough I don't know if it will work.I hope you'll help me.
Thanks for your time,

Pantxe

Pd: English isn't my morhe thongue. Sorry for the mistakes.

 

[shumifan50]

That controller will not work, it controls the speed of a motor. A servo goes to a specific position depending on the input to the servo. The servo motors are typically just on or off with no speed control. Added to which a windscreen wiper gearbox has way too much play.

I would not know what to recommend you use, but you could look at stepper motors which are cheaper.
You might be better off asking for advice on a radio control model forum.

 

[Arouse1973]

So the size is what about 1/5 scale? Then you need a hefty servo. We used to use something like this.
http://www.mattysmodels.info/Steeri...y_15_scale_part_no_81801/p989433_5309211.aspx

Adam

 

[pantxe]

What I exactly want to make is this:

The problem is that I don't know what type of controller does he use.

 

[jpanhalt]

Use a high power servo for simple control as Adam suggests. Here's another source:

https://www.servocity.com/html/hs-1000sgt_servo.html

If you go to the home page, you can find a table of specifications to help search for a smaller, perhaps more suitable servo.

John

 

[shumifan50]

I'm guessing homemade

 

[shumifan50]

Have a look at this artice
Internal workings of a servo

That opens some interesting possibilities. Bearing in mind that the gearbox on a wiper motor will never be accurate as it has too much play.

You could open a normal servo (I have never done this,but it will be like micro-surgery) and disconnect the circuit from the motor in the servo. From the article, you should find 4 wires(or so) from the motor and from a resister pot. You need to connect the shaft of the new resistor pot to the output shaft of the wiper so that the pot is adjusted when the wiper motor moves. Then connect the new resistive pot in place of the one in the servo(you will have to measure the value of the original in the servo).
The next thing will be to add some driver circuit to boost the motor driving voltage from the servo circuit and to handle the wipermotor current.

This might work, but will require some fiddling. You could even build the suggested circuit to do the control.
The cost of a hobby servo is around £10

 

[pantxe]

This type of servo are too expensive and they are more weak than a wiper engine and they can't make so much force. That's why I want to build that. Anyone who knows what type of controller dos he use in the video?

 

[shumifan50]

Have you read the article at the link I posted? It gives you all the details.

 

[pantxe]

Sorry I had not read it although after havig read Im almost in the same as I dont have almost any knowlwdge about electronics. I only want to have to connect some wires in the correct place and no more as shown in the video. Anyaway thanks for the info.

 

[shumifan50]

The controller chip can be bought at
M51660L controller chip

It will never be as simple as just connecting wires. You will need to provide some feedback from the wiper motor to tell the control circuit what the position of the motor is. I doubt you can buy a control circuit 'out of the box'. The one in the video looks homemade. Try to email the guy and see if he'll make you one but you will still have to provide the feedback.

Or the easier way is to hack a hobby servo as I suggest above.