How To Modify A Servo For Continuous Rotation
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- เผยแพร่เมื่อ 25 มี.ค. 2018
- Here is a full video guide to modifying a Turnigy TG9e Analogue Micro Servo for continuous rotation. Modifying a servo for continuous rotation opens up a number of possibilities for new Arduino projects, the modified servos essentially function as a PWM variable speed and direction motor which can easily be controlled by an Arduino or similar micro controller.
The process is very similar for other servo models and different sized servos.
Visit this link for the full guide along with purchase links for the tools and materials - www.the-diy-life.com/how-to-mo... - แนวปฏิบัติและการใช้ชีวิต
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Rather than "drill slightly larger" the output gear, I suggest cutting off the stop-tabs in the potentiometer. It will keep the output gear tight on the potentiometer's shaft and preserve the sturdiness of the gear cluster. Rounding out the final gear to free it from the half-moon shaped shaft-end on the potentiometer will result in sloppiness, cause gear slippage and could render the servo useless.
To remove the stop-tabs off the potentiometer, take the pot out of its housing, unsolder the three wires. The middle contact-tab is also the retainer-clip for the pot shaft, so drill out and pull it away from the pot to free the shaft. The spinning plate with the stop-tabs stays attached to the shaft, cut or shave off the stop-tabs. You can now solder together the three contacts on the potentiometer with a thin section of wire, which will secure the retainer-clip part of the middle tab around the base of the shaft. Reassemble, you're done.
This was really helpful! Thank you for making this video!
Absolutely brilliant. I love you. Exactly what I needed.
This music is rage inducing.
Michael, this goes against some of the TH-cam videos about using matching resistors or gluing the potentiometer in a neutral position. Don't get me wrong, I like your solution very much. Thank you sharing.
Hi Murphy, thanks for the great feedback. It seems like this solution works on a wide range of servos but not all of them. Some may still require matching resistors or gluing the pot in place.
Smart idea.. Thank you man.
thank you
The potentiometer has three connections.
1 - VCC
2 - Wiper
3 - VSS
If you connect all three, you're shorting the circuit. Whatever servo you used might be tolerant of this, but it's still a horrible idea. What you should do is center the potentiometer, and then disconnect it from the drive shaft.
I audibly shouted "WHAT?" when they shorted VCC and GND together, that's a no-no
@@littlenyancat5754 yeah I also had a similar reaction. why would you tie all 3 wires together... you can just tie wiper and 5v together and it should work even without resistor.
What is the circuit that control the servo? I need to design something what will be working in similar way but for 360° :) Thanks in advance!
Thanks for the help. I fatally injured myself after listening to that whole song yo!
Great video Michael! Question though, what is that device you are using to control the servo, called? I assume a PWM controller or something of the sorts. Where can I buy one? Better yet, do you have a video on how to make such controller?
Thanks Chad! Yes, its just called a servo tester, it's a basic PWM controller that you could build using a microcontroller like an Arduino. I don't have a video on making one as they're usually cheaper to just buy as a standalone unit - I think the one in the video cost about $4.
seems a bad idea to short the ends connecting to the potentiometer. If the circuit uses 5V to probe the resistance then how much current would it draw if you short them together?
amazing. I will do this tomorrow :)
Thanks , so we can command it as DC motor with his driver?
Yes you'll essentially land up with a PWM controlled reversible DC motor.
@@MichaelKlementsThanks for the video buddy, but I am unable to reverse it.
Is there a way of making the servo only move in one direction? So that in effect you turn the controller to the left / servo off - turn controller to the right / servo rotate?
Not with the servo tester I've used here, but you could use a small micro-controller to do what you're asking.
How about if I wanted it to turn a certain number of revolutions, then stop. Same in reverse. And be able to adjust or set the number of rotations for what I need…. I’m trying to create a little raise/lower mechanism for a small platform with a gimbal mounted to it.. to be able to raise and lower a gimbal+cam from the bottom of a UAV.
To do this accurately you'd be better off getting a multi-turn servo. You could also probably "hack" something together to drive the potentiometer from the small platform you're referring to - this would just extend the servo limits.
what servo tester did you use I have a science fair project to do so I need to know
Hi Miro, it’s just a cheap one available on Hobby King. Just search for servo testers on their site.
@@MichaelKlements Hi Michael, I could use an Arduino as a 'servo tester' right? Maybe using the Arduino Pot Knob sketch or maybe a digital knob sketch? What do you think?
I did this but the motor doesn't even power on now and it gets warmer. Any idea?
Those 3 wires you shorted together were 5V and Ground. This is a bad idea!
Does this decrease the amount of torque produced by the servo?
The amount of torque produced by these servos is proportional to the “error”, so you’ll get less torque at low speeds but you should get the full servo torque at medium and high speeds
Can you still program in the Arduino IDE for the servo to move a certain amt of degrees (EX. 370 degrees) and then stop?
No. Essentially he turned the servo into a DC motor any aspect of it being a servo was destroyed.
@@amelliamendel2227 is exist some real servo with continuous rotation and feeback i need to make a robot turret
@@omnianti0 sure, you can buy a continuous rotation ROBOT servo (not a hobby servo), but to be honest with you. With what you're likely to spend on that, you'd be better off getting a steeper motor maybe a small 34mm nema 17 or such.
The main advantage is the positional feedback you'll get from the stepper motor. It will know where it is in it's rotation. A robot servo (the ones with that feedback) cost a lot more than hobby servos, that will only move to a position you tell it, plus the stepper motor has multiples more torque power for the money. You'll never see a servo motor on a 3d printer for example.
@@amelliamendel2227 not true a steeper have no absolute position when reset it just sit where it stoped
i need a real servo reference for continous absolute rotation
Great video, only my servo started to get very warm (it didn't work). My solution was to put the potentiometer back and twist it to the middle and then glue it.
(This wasn't actually my solution but that from Flitetest)
Glad you managed to get it to work! Yeah, some servos are happy without the pot, some need the pot or some form of resistance to be connected.
Okay tried it again with another servo and that one isn't working either so now I have 2 broken servos from watching this video
umm, you just created a dead short between VCC and GND. The three wires going to the POT are VCC, Wiper and GND. You are assuming there is an external resistor in the servo, a fair assumption, but if you are wrong things are going to go VERY badly.
I watched this and thought the same. I ended up centering servo and then disconnecting the linkage between the shaft and pot.
why keep the wires connecting the drive board to the potentiometer at all. since all thats done to them is removing them and covering them with electrical tape
They are not just disconnected, they are all joined together. You could also do this by soldering a short jumper across the three terminals.
sadly didn't work on my servos
Very helpful however i couldnt understand a thing. Can we just remove end stop from gear. is it enough for allowing servo rotate 360 degrees? if not why we play around with circuit boards?
There reason is he's taking out the servo functionally and stripping it down to a dc motor, all servo functionality is destroyed. There's no position information it's just on or off forward or reverse.
Just to correct Amellia’s comment. It does not simply have on off forward or reverse. The servo speed is proportional to the position error so the higher or lower your PWM signal is off of the off position, the faster the speed. You get full forward and reverse with speed control as well.
@@MichaelKlements It's been a while since I watched this video, so please excuse me if I'm wrong but didn't you completely remove the pwm board? If so you could control the speed just like any other DC motor by using an analog out controlling the voltage thus controlling the speed. So, as I've already stated, if you remove the pwm board then all you're left with is a dc motor. If you can control the speed it's simply the voltage and has nothing to do with pwm. Test it yourself with a voltmeter if you don't believe me. You cannot remove the pwm board and then try to say you're still controlling the speed via pwm, no, no you're not.
Why did you strip the potentiometer?
You need to fix the potentiometer position/resistance. So I did this by disconnecting it and shorting the wires, leading to a fixed position being registered. You could also leave it connected and glue it in place and then drill out the gear/arm connected onto it so that it turns freely on the potentiometer.
@@MichaelKlements I disconnected the wires and stripped them together but the motor wouldn't stop rotating and always kept the same speed, then realized the wires were not connected to each other because they weren't sticking out the cable.
Then I tried to fix that but ripped a cable by accident in process so I have to get it soldered tomorrow.. is nonstop rotation a problem because the potentiometer cables aren't connected?
@@MichaelKlements I still don't have any movement for some reason, think I messed up the potentiometer somehow. I had constant movement without stopping, shorted the 3 wires and now no movement or any reaction to Arduino. :/
man those other vids and resisitors were turn off you simply showed it all I wanted to see.
Video 10/10. Backing music -0/100
I followed the video and now my servo is not working🤘
Candyland horror movie 👌🏼
I did this and the servo just rotates at a constant speed no matter what the pwm is set too. Any idea what I did wrong?
Hi Chari, did you remove the potentiometer or glue it in place? Your potentiometer needs to give a "centre" or close to centre signal to the processor on the servo in order for it to stop at that point. Any PWM signal away from the centre point drives the servo in the opposite direction at increasing speed based on the error. If your servo is just turning at constant speed (I'm guessing maximum speed) then its likely that is is getting no signal from the pot or a signal at either one of the pots limits. Try re-centering the pot or putting equal resistance between the three wires fed to the processor from the pot and this should solve the problem.
Did you find the solution to it?
@@MichaelKlements Thanks for the reply! I completely removed the potentiometer since in your video you completely disconnect it. It wasn't like your pot, it had 3 steel pins and it was directly soldered to the board. After cutting the 3 steel pins I pushed them together but didn't solder them. I'll go to a friend to solder them and see if this makes any difference.
@@charimuvilla8693 Hi Chari. Make sure that the metal pins are well connected, it may be worth soldering them together. If that doesn't work, its possible that the different design on your servo won't work without the potentiometer connection. Try reconnecting the potentiometer and rather gluing the pot in place around it's mid point. You'll also need to drill out the plastic gear which turns the pot with the arm such that it can turn freely without turning the pot.
@@MichaelKlements Yes one of these two should be the right solution. Thank you so much for your help!
This isn't working... Motor continues to run in one direction. Tried resisters too.. same problem..!
Hi Rohit, its possible that the different design on your servo won't work without the potentiometer connection. Try reconnecting the potentiometer and rather gluing the pot in place around it's mid point. You'll also need to drill out the plastic gear which turns the pot with the arm such that it can turn freely without turning the pot.
@@MichaelKlements Thank you.. this method works..
Wow, holding the gear between your fingers while you use a drill to enlarge a hole. Great lesson in what not to do in your shop. Put the gear in a vise.
This is a soft plastic gear that is less than a centimetre in diameter, if you put it into a vise you will squash the teeth and make it unusable.
This didn't work on my Servo.
Just short 5V directly to ground... Yep, that will ensure the motor doesn't die.
fo real wtf is going on in this vid
Congrats you turned a $1.45 servo into an .85 cent DC motor, simply brilliant, lol
Except that you can’t connect a DC motor directly onto an RC receiver or PWM output.
@@MichaelKlements tought you can bu a 360 ""servo"" that not contin potentiometer for half
with this modification you can control the direction of rotation without backsurge protection required or an h-bridge
@@andrewcummings6940 maybe a real dc motor for the same price is more optimised by size and material their cheap h bridge too
@@MichaelKlements And you get the gearing and the splined shaft. And a shape format that has easy to source (or 3D print) mounts. I think all that's worth the tiny price disparity.
Another totally useless technocrap music video
congrate you destroyed the feedback of a servo and downgraded it to a basic dc motor insetead of buying a cheap easy to control motor
Have you got a link to a PWM controlled DC motor and driver for less than $2?
@@MichaelKlements no sorry it start to 2.5$