wiper motor steering servo

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S

superchip

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Hi I wonder if someone can provide me with some info regarding the item- http://www.coolcomponents.co.uk/simpl...#, I read the description carefully and also looked at the manual regarding this item but my question remains unanswered mainly because I'm totally new to electronics and as a result I don't really understand the jargon. I am trying to build a homemade servo using a windscreen wiper motor to use as a steering system on a large scale car I'm building, I understand this item utilises differential steering but I don't want to do that. All I need is to control the wiper motor just like a standard hobby servo, left, right and auto centre, I have searched all over the Internet and plenty of people have done this but they seem to keep their accomplishment a closely guarded secret, and I can't help thinking I'm missing something as I can't seem to make it work properly because with the electronics I have I get terrible motor jitter when the potentiometer is in the center position so I'm starting to think the driver board I have isn't the right one hence the reason I'm looking at this one. Any info anybody can provide or if anyone knows of a better board to look at I would be very grateful. All the best, John :)
 
Sound to me like its a vibration issue on you pot used to center you motor
We have it on our servos it won't stay centered it bounces left then right and won't stop it more noticeable with weight off car wheels off the ground
It may not be your board it may be your Raido setting called deadband you may be able to make it wider if it's a digital radio you should be able to
What it means is 0 is center an L1 is first step left 0 and first step right is R1 so when servo moves so make it wider L3 0 R3 to stop the bounce back and fourth of the pot trying to center servo your working digital to analog so Widen digital to help slower analog hope that helps let us know
 
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nitrocat said:
Sound to me like its a vibration issue on you pot used to center you motor
We have it on our servos it won't stay centered it bounces left then right and won't stop it more noticeable with weight off car wheels off the ground
It may not be your board it may be your Raido setting called deadband you may be able to make it wider if it's a digital radio you should be able to
What it means is 0 is center an L1 is first step left 0 and first step right is R1 so when servo moves so make it wider L3 0 R3 to stop the bounce back and fourth of the pot trying to center servo your working digital to analog so Widen digital to help slower analog hope that helps let us know
Click to expand...

Hi nitrocat, thank you for the info. Maybe I should elaborate a little on my setup as I realise in my first post I didn't really mention it Lol. I take it you have heard of hacking a hobby servo for the internal board and pot and connect it to a h bridge to power a 12v brushed motor, so I have an arduino motor controller board amplifying a pulse signal from a hacked servo which provides the rc signal and position feedback. 5v powers the controller board and 12v powers the wiper motor. The radio I'm using is the stock kyosho off a mad force I had a while back which I think is 27mhz. If I hook a normal servo to the receiver I get no jitter but if I try my wiper motor setup I get bad jitter in the pots dead band and no amount of adjustment on the transmitter or the pot rectifies it. I did read somewhere that I may need a Schmitt switch between the hacked servo and controller board but as I say I'm no genius with electrics do I need a second opinion before I start buying components I may not need Lol again, thank you for the info and look forward to hearing any other ideas you may have :)
 
How much tork are you going to need to turn car and how much are you willing to spend and how fast is it going to go
First 27mhz has a lot of interference
As I read you post it may be a feedback off the 12 volt motor you may have to put capacitor on end bell of it to help get ac out of it
 
nitrocat said:
How much tork are you going to need to turn car and how much are you willing to spend and how fast is it going to go
First 27mhz has a lot of interference
As I read you post it may be a feedback off the 12 volt motor you may have to put capacitor on end bell of it to help get ac out of it
Click to expand...

To be honest I never really thought of these factors, thank you for bringing them up. I never actually determined what scale this car is going to be so I'll give some rough measurements. I would say its about 3 1/2 feet long, around 2 feet wide and a foot high free standing. Its going to be powered by a 49cc petrol scooter engine and the wheels are from a sack barrow. The engine is driving a rear solid axle via a lay shaft and with the gearing I think it'll achieve around 50+ mph but I'm probably wrong lol. I wish I could supply pictures but the chassis is only half done and I have to redesign as I go along. Maybe as I progress I'll take pictures and post them in this thread but there's really not enough to show yet plus in not happy showing it until it's a bit more polished lol. But this is why I need to make this custom servo because of the wheels I'm using, once this servo is working properly it'll have enough torque to take a finger off no problem, off the shelf servos just won't cut the mustard lol. To get back to your reply though, do you mean solder a capacitor between the h bridge motor + output and the wiper motor? If so which capacitor should I try? And yes I thought the radio may be the problem, looks like I'm gonna have to get a 2.4ghz system lol Many thanks for you patience, John.
 
Any size cap as long as it's rated for I think you said 12 volts
Now high tech has a servo HS1000 SGT it has 1527 of tork it will turn it
and take finger off if your not carful
I have one in a 36 lb truck and it's 32 inches long 24 inch wide with a 11 hp motor
also you may want a killer B kill switch it's. A safety item it kills motor if loss of signal 3e2a7eva.jpg
 
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nitrocat said:
Any size cap as long as it's rated for I think you said 12 volts
Now high tech has a servo HS1000 SGT it has 1527 of tork it will turn it
and take finger off if your not carful
I have one in a 36 lb truck and it's 32 inches long 24 inch wide with a 11 hp motor
also you may want a killer B kill switch it's. A safety item it kills motor if loss of signal 3e2a7eva.jpg
Click to expand...

Many thanks for the info nitrocat you're a superstar. At this present moment I'm operating on a shoe string budget which rules out buying the hitec servo, however I think you were onto something when you mentioned my problem could lay in my transmitter as I seem to remember my setup working better on a 2.4ghz radio I had spare ages ago but the receiver got fried, hence why I'm using the kyosho. But going on you're advice and I have ordered a new transmitter, not an expensive one by any stretch of the imagination but should be good enough for now :). I will most definitely be getting a killer b purely because once its finished I would dread to think what damage it could cause if it ever lost radio signal lol. Many thanks again for your help, I will update this thread again once I figure out my servo setup and will post some pics :) :)
 
Nitro I'm running the new 1000 in a brushless setup my 900 s still going strong can you believe all the poop we went through before these came out. I have a box of 100$ + servos some total junk some good for parts. I have more money in servos than two stock trucks hanging around love the hitecs
 
I have two trucks and not one servo has gone bad on me yet nock on wood but my driver says it's the best mod you can do for truck
He told me I wasted my money till he drove it first time that's the last time he said that
I think that the clutch was big to it makes it go like a 1/8 scale
 
So I received my new 2ch 2.4ghz flysky radio yesterday and unfortunately I'm still getting the same bad jitter in the dead band. I've been researching my problem to discover a solution and I found out I shouldn't be connecting the hacked servo directly to the h bridge and I think I may need a comparator circuit between the hacked servo and h bridge but I'm not fully confident whether I'm right or not. I still haven't tried a capacitor on the wiper motor as I haven't had the opportunity to go to an electronics store. If anyone on this forum ever made a wiper motor servo please could you help, you'll be doing me a good service and I would be eternally grateful for your help. Thanks a lot, John.
 
I'm reviving this thread for two reasons, 1) I think the info may be useful for others and 2) I have some small progress developing my particular homemade servo.

So I got a servo Thor-15 motor controller off a German web page (its the one with the feed back pot attached) and I'm quite happy with how it performs. There is one niggling problem that still remains though and that's three fact I can't seem to get the controller to auto centre the wiper motor it's controlling. Now the product description states that the propose of the controller is for high power steering systems so I'm using the right item for the intended purpose. It moves the motor output shaft left and right no problem via either there pot or tx but it just will not centre by its self and its driving me crazy. I have had the pot linked to the output shaft of the motor but all it does is rip the linkage off the servo horn on the pot at full swing left or right. If anyone can help I would really appreciate it. Many thanks, John.
 
Does the servo arm move when you turn the centering pot left or right
Sorry just read it again you say it does
I know it's a very fine tooth gear that runs that on small servos
Do you think it's to big of a jump on yours
 
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Thanks for replying nitrocat I appreciate your dedication to my thread :). When I actuate the wiper motor with the pot it increases the speed of the motor either way and the same happens using the tx too which I expect should happen. I can achieve very fine modulation in both directions and the hunting when the pot is centered is non existent now with this controller which I'm profoundly happy about. Its getting the setup to auto centre now that is deluding me. As I mentioned before when I have the pot mechanically linked to the motors output, left or right, once the output shaft goes full swing as far as the linkage allows then rips the linkage off the pots servo horn. Actually that's kinda funny thinking about it because that's not what's mean to happen, a normal servo positionally mimicks the movement of the tx but this isn't happening here. With the pot linked to the output shaft, left or right from the tx just swings the output shaft to its mechanical limits. I just can't see what in doing wrong as I've seen a few YouTube videos with the exact same setup and it works flawlessly for them and as far as I can tell I'm not doing much different so I'm stumped lol
 
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I would just like to add that I've practically scoured the Internet to find a solution but no dice. The linkage I'm using is a piece of threaded bar with some 1/10 scale rc rod ends and once set up there virtually isn't any slop. Just thought I'd mention lol
 
nitrocat said:
Just set the end points on transmitter to end of travel where linkage starts to over travel and bend it's self up
Click to expand...

Hi thanks for the suggestion but as far as the Internet is concerned my fs-gt2 transmitter doesn't have adjustable end points which kinda bums me out. If I want that adjustment I would have to get the fs-gt3. Oh well looks like I'm buying another radio lol
 
Spectrum is good and not to expensive the 3 s should do all you need or pro 3 R is a little over kill
The reason 3 Chanel is for kill switch you can also pick up used for very good price
Just be careful the silver transmitter will not work with the black receivers
But black transmitters work with all receivers
 
Thank you very much for the info I'll definitely keep that in mind. I'm not trying to be a skin flint but I've looked on the Internet and there is actually a way to add a pot to the transmitter to give end point adjustment. I know it's easier just to get a radio with the functionality already on but that can be an avenue worth exploring too. Although I have overlooked the need for a third channel so I'll be looking for a suitable radio anyway whether it be spektrum or fkysky lol
 
I can tell your a builder/tinker have fun ps you don't have to have 3rd Chanel for kill switch you have to turn transmitter off to kill motor (no steering or brake ) like that
 
nitrocat said:
I can tell your a builder/tinker have fun ps you don't have to have 3rd Chanel for kill switch you have to turn transmitter off to kill motor (no steering or brake ) like that
Click to expand...

Hahahahaha how can you tell? Does it really show that much? :D for a few years I've been wanting to build a large scale buggy because a) its mostly an easier build and b) I believe a true scale model needs a proper petrol engine and although there's hpi Baja and rovan and others I wanted something bigger and in my view the building part is the most fun. But seeing your creation actually move the way you envisage fills you with so much joy and the pride you feel when you can turn around and say 'I built that' is fantastic :D. I shall post again if I come across anymore problems or if I actually I figure this minor hiccup out I'll be sure to post my findings. Many thanks for now nitrocat you've been a star ;)
 
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