This is a quick and easy walkthrough on how to modify a HiTec Servo and make it a normal dc motor with gears.

To see how you can control your motors with the Arduino visit this instructable:


Step 1:

1. Say hello to your servo, and say goodbye as well because what we are going to do here is irreversible.

We will hack essencial parts of the servo and it won�t be a servo anymore, it will be a powerfull dc motor with gears.

Step 2:

2. This are the tools we need, I think I don't need to describe them :)

Step 3:

3. Ok let's begin.

Start by removing the screw on the top.

Step 4:

4. Remove the four little screws on the back of the case.

Step 5:

5. Open the case.

Step 6:

6. And remove the top carefully.

Step 7:

7. We can see the gears inside the case. We only need to remove the first two gears, no need to remove the others.
Be careful enough and avoid contaminate the grease that surrounds the gears.

Step 8:

8. Remove the black and white gears.

Step 9:

9. Now it's time to remove the circuit on the bottom of the case, see the next foto.

Step 10:

10. Use the soldering iron and gently remove the circuit.

Step 11:

11. You can see now the dc motor.

Step 12:

12. Cut the wires that connect the potenciometer to the circuit.

Step 13:

13. Now remove the little screw inside the case.

Step 14:

14. Press the potenciometer thingey to remove it.

Step 15:

15. Parts we don't need anymore.. I wasn't carefull enough and broke the circuit.. no problem, we won't need it anymore, at least I don't know what I can do with it... :)

Step 16:

16. Now grab two wires with +- 15 cm, depends on your needs.

Step 17:

17. Grab your soldering iron and solder the wires to the motor pins. Note the red mark on the motor.

Step 18:

18. Now we are going to remove the thingey that tells to the servo to spin only 180º.

Step 19:

19. Remove the white ring.

Step 20:

20. Make an horizontal cut.

Step 21:

21. Then make a vertical cut.

Step 22:

22. The thingey is removed.

Step 23:

23. Remove any imperfections you see.

Step 24:

24. Put the white ring back.

Step 25:

25. Ok, now we can put our gears back.

Step 26:

26. Like this.

Step 27:

27. Time to close the case.

Step 28:

28. Before closing the bottom, perform a knot on the wires, and adjust them to the border of the case. This will protect the solder business we've done before.

Step 29:

29. Close the bottom part, and put the screws back.

Step 30:

30. Say hello to your brand new DC Motor.

Step 31:

31. You can use the wires and connector to be an extension to another 'real' servo, or for sensors, or for anything else.

You can use the potenciometer as well for some future project, maybe to control the motor speed?
So you basically turned a servo into a regular DC-motor? Why not just buy a DC motor with a gearbox in the first place?<br/>Wouldn't it be smarter to turn it into a continuous rotation servo (which is even easier)? That way you would get speed control of the servo. I've done that, and my robot runs great with it =D<br/>
<p>because you often get used servo motors for dirt cheap on ebay, or even ones with the electronics fried, for far less then a geared dc motor, with digital servos becoming the norm now, old analog servo's will go the way of the dinosaur anyway, in other words really cheap, the digital ones are awesome, you can set center, speed, end points, all kinds of parameters, and it's saved right on the servo board, no more burned out servos as the servo will always know it's mechanical limits, no matter what the controller tells it </p>
Ya but this is good if you fry the board inside a servo. Reduce! Reuse! Recycle!
The servo h-bridge can be slightly less of a driver than needed in certain applications. The servo circuit has a limit pulse drive of the motors. Using your own h-bridge (FET based) and electronics gets more of the power to the servo motor for better torque and speed.
<p>Can the servo 180 degree stop be positioned so that the servo will operate 270 degrees or something more than 180 degrees but less than 360 degrees ?</p>
<p>yes you can. it is crude but if you have a micrometer and a protractor you can. under the top (servo arm gear) cover are two set points around the whole. going back to this instruct-able, a gear needed to have a white piece removed from it and cleared of dubree. that was the rotating knob ill call it that made contact to the set points which stopped the potentiomenter in turn stopping the rotation of the motor. you can use the protractor on a sheet of paper. create a center point on the paper, put focal point of protractor on said point then marking 0 and 270. draw lines from marks to center point. that will give you a constant degree line for various diameters. get the radius of the &quot;knobbed gear&quot; then use micrometer to mirror a new mark you'll make just shy of the radius. that is a stencil that you can put on the servo lid to then drill two small screws that the knob will hit stopping the motor. dont forget to factor in the radius of the screw you use. and if you dont have a micrometer just use a sharp pencil and the edge of a paper </p>
<p>As far as I am aware I don't think that is possible, but I have never tried such a thing. Even if you could position the stop in the way you are saying, I think it wouldn't work properly due to all the servo electronics being prepared to work with the 180&ordm; rotation, but it is only a thought. </p><p>I wish you good luck :)</p>
Is there anything else besides a soldering Iron that will work?
I'm new to this (but learning) so maybe my question is a bit obvious:<br>When I hack the servo as described in your excellent Ible, will it become a continous spinning motor (when power is applied)?<br>Or in other words, can I still controll the angle that I want to turn it?<br><br>I'm looking for a servo that I can control accurately, but I want to turn it more than 360 degrees.<br>Hope you can help.<br><br>
Unfortunately no, your servo will behave like a normal geared DC motor. If you need that specification you will need an encoder, there are many tutorials about DIY encoders. Good Luck ;)
Thanks! Could you recommend a good DIY tutorial on encoders, because I did a search myself and found it hard to select a good one.
depends on what kind of approaches you prefer, just to mention a few:<br><br>http://letsmakerobots.com/node/17597<br><br>http://letsmakerobots.com/node/12293<br><br>http://www.societyofrobots.com/sensors_encoder.shtml
Thanks! I'll look into it.<br> I'm thinking of making a robot (Arduino controlled) and it needs to ride over an exact pre-calculated distance (the wheels rotate more than 360 degrees).
if You want it to move Your given angle, or just spin --- use steppers (pretty slow, compared to DC, but precise) -- In Your case -- the best solution.. <br>Otherwise use DC with optical encoder..
Excellent post. Thanks, I was able to follow it step by step and modify my servo. Thanks, and keep up the good work
You can use the servo board to make an electronic speed control. Make a note of the (+) solder pad before removing the motor from the servo board you can then use it to drive the gate of a power mosfet (such as the IRL 520N) to have a low power ESC for approximately $2. Be sure to put a 500-1k ohm resistor between the gate and motor output of the servo board. The PWM signal from an R/C receiver or microcontroller can now drive a small motor with variable speed.
very interesting!!! it would be cool to see an instructable with this subjet :)
I wish I could do this in reverse. I have 50,000 dc motors and want to make them into servos.
where did you get that many motors?? Ebay...??
maybe like 30. I take lots of things apart
wow 50 thousand? I have half a million XP
Sometimes the thing is on the thread of the gear,so if you remove it it still won't fully spin
Good write up, very clear pictures. If you haven't fried the board you can just replace the pot with a pair of 2.7k ohm resistors and you have a radio controlled gearmotor.
You can optionally make it a much faster gearmotor (with less torque) at this stage if you want. Remove the left black gear entirely, and glue the bottom white gear to the top black gear.
Interesting, but why dismantle an otherwise good servo instead of picking up a basic DC motor from, say, Radioshack? Unless the servo's shot I wouldn't think this would be an economical way to get my hands on a new motor.
This servo has a added gear box, so not only getting a dc motor you get a good dc motor complete with gearbox :)
Yes that&acute;s it, you get a geared dc motor, inside of a nice case with mounting holes, and with many servo horns<br/><a rel="nofollow" href="http://www.futaba-rc.com/parts/servo-horns.gif">http://www.futaba-rc.com/parts/servo-horns.gif</a><br/>
Yep i have seen this hack to many to count but you have done a great i'bles 5* <br/><br/>Have Fun <br/>

About This Instructable




Bio: Designer & digital artist
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