Remote Control Question

mtierney5

Hi guys and girls,


I have a 4yr old son who has special needs and who is a car and tractor fanatic. What I’m looking for is a John Deere ride-on battery powered tractor. These are pretty much easy to get from the UK but my problem is that my son would not be able to drive it himself. So, I need one with a parental remote control so I can drive it around with him sitting on it! Here lies the problem!

Last year we got him this remote control ride on car but he has out grown it. (http://cgi.ebay.ie/RIDE-ASTON-MARTIN-STYLE-CAR-MP3-REMOTE-CONTROL-/250699711644?pt=UK_Toys_Games_Outdoor_Toys_Bikes_Ride_Ons_LE&hash=item3a5ede049c). So we are desperately looking for something to replace it.

I have found this one which is exactly what we need but it has no remote! http://www.toysrus.co.uk/Toys-R-Us/Bikes-and-Rideons/Battery-Powered/12V-John-Deere-Ground-Force-Tractor-and-Trailer(0080200)?cm_mmc=Affiliate/Awin-_-71959-_-Feed-_-2V John Deere Ground Force Tractor and Trailer&aw_link=aw

I’d really like to get him a John Deere Tractor as he gets so excited every time he sees one and I know he would burst with excitement if he got his own little one!

So what I’m hoping for is that someone might know if a remote control device could be fitted to something like this. Lots of cars like this (smaller) come with remotes but when they get bigger they dont do the remote anymore, because 99% of kids dont need them!

This maybe a long shot, I think, but someone may be able to help, and I have to try!

If anyone knows a better forum to post this on the site please advise.

Many thanks in advance,

Martin.

Bruthal

As i had said to you on the electrical forum this big servo http://www.tonegawaseiko.co.jp/pro/e_pro02.html would work for the steering and a normal one for the throttle pot, both controlled from a radio controller,

But that big servo cost is a bit prohibitive. But it might give others here an idea,

syl77

How did the electronics handle the RC car, would they be able for the Tractor?, would there be any components worth transfering over?..
Tx/Rx .... battery, motor, servos...etc....
Other than that you are looking at what Robbie suggested....
Best of luck......

Bruthal

Another servo the same make as that other big one is about 160 euro,
http://www.troybuiltmodels.com/items/PS050.html

Should be strong enough for steering but still expensive enough when you consider a radio system is needed as well.
Our Mod on this forum might have some ideas, its an interesting one anyway.

coolwings

Looking at the photo, I'd be inclined to fit a metal rod from left to right side through the steering column, the rod protruding about 6" each side, rounded ends, and drilled near the tips
Fit a sail winch servo in the body with a continuous loop of dacron cord round the winch and to the ends of the rod.
The winch would then pull the operative side back and release the other side, a pull-pull system if you need to search online for a diagram.
A sail winch servo has about 11 to 13kgs of torque, and about 9 to 13 inches of "draw", and this might be sufficient.
The steering wheel above would have to be disabled, by cutting the steering column, and reattaching but with a free movement.

Just my thoughts on one way to approach it.
Let the ideas flow in and compare pros and cons I guess.

Bruthal

coolwings wrote: »

Looking at the photo, I'd be inclined to fit a metal rod from left to right side through the steering column.
Fit a sail winch servo in the body with a continuous loop of dacron cord round the winch and to the ends of the rod. the winch would then pull the operative side back and release the other side, a pull-pull system if you need to search online for a diagram.
A sail winch servo has about 11 to 13kgs of torque, and about 9 to 13 inches of "draw", and this might be sufficient.
The steering wheel above would have to be disabled, by cutting the steering column, and reattaching but with a free movement.

Just my thoughts on one way to approach it.
Let the ideas flow in and compare I guess.

Yea i thought of the sail winch type one or continous rotation type but i did`t think it would have that much torque, 13kg would`t be too bad on a small pulley on the servo pull-pull to a relatively wide rod. I have converted normal servo`s to continous ones as well before. But the average ones would not have the torque.

mtierney5

coolwings wrote: »

Looking at the photo, I'd be inclined to fit a metal rod from left to right side through the steering column, the rod protruding about 6" each side, rounded ends, and drilled near the tips
Fit a sail winch servo in the body with a continuous loop of dacron cord round the winch and to the ends of the rod.
The winch would then pull the operative side back and release the other side, a pull-pull system if you need to search online for a diagram.
A sail winch servo has about 11 to 13kgs of torque, and about 9 to 13 inches of "draw", and this might be sufficient.
The steering wheel above would have to be disabled, by cutting the steering column, and reattaching but with a free movement.

Just my thoughts on one way to approach it.
Let the ideas flow in and compare pros and cons I guess.

All sounds good lads, anyone know someone who'd be willing to do it????

mtierney5

I though a few pics of the old car might help, i'll try to strip it down a bit to get more detailed ones, maybe transfering stuff from this one might work....

this is the under side anyway....

mtierney5

this is what is under the seat....

i think its a very basic system really, the whole car only cost €100 so it cant be too complicated or the parts too dear.

mtierney5

this is the remote control, again a very cheap light plastic, but works fine...

mtierney5

ok, this is under the bonnet/behind the steering wheel....

if anyone wants pics of a specific part etc just ask...

mtierney5

i think the black box behind the battery under the seat is the remote control reciever. Theres a single brown wire from it thats just strealled along the under body. An aerial i presume.

Then there are three sets of wires leaving it, one set runs along the under body to behind the steering. it then branchs into two, 3 wires go to a switch for power on/off. two more go into the blcak box behing the steering wheel.

The second set leaving the box behind the battery is also running along the bottom and goes straight in under the pedal that makes the car drive.

The third set goes directly to the motor on the rear wheel which can be seen in the pic of under the seat.

The car drives by the child pressing this pedal, but can be over ridden by the remote control.


Hope this helps!

mtierney5

this is the set up on the dash from the front and behind

Bruthal

I myself think its probably better to start afresh with the new tractor, not using parts from the old one. The main problem is always going to be the steering. I think whatever happens, the new tractor would need to be got and looked at and see what can be done with it.

Bruthal

Another servo possibility for the steering. Id say that would work, so if you had the tractor and you can get all the bits i`d have a look at it anyway.


Here is the unit, looks like a good possiblity to me, any other opinions?
http://www.servocity.com/html/spg755a-bm_standard_rotation.html

Bruthal

I have been looking at videos of that tractor and i dont see any reason it cant be done, you would need the tractor first, so we can see how to proceed, but it can be done i would think.

A few euros of parts would be needed, i dont know exactly how much parts would be needed, the steering would be the bit that needs an extra bit of power in the motorised servo that moves the steering, but looking at the kids on the tractor in videos it seems very light on the steering, but that would become more clear if we had the tractor to look at. Another servo to use in place of the foot pedal, and also the forward reverse control, but these servos would be cheap. So thats my view on it anyway.

mtierney5

this is the radio unit i have

coolwings

Should be fine.
But if you put in one of those big high torque servos, they really suck power, so the little 4 x AA battery box for the blue receiver will have to be bumped up in size to a 4 x C cell battery.

Bruthal

It will be a servo similar to the winch ones you mentioned in a geared drive id say, something like this, might not be too bad on the AA`s but the C ones are not a bad idea.

The only thing about the 27 mhz is prone to interference from other radio control cars other kids might be using, Other than that it will work fine. Can try it anyway,

Forgot servo photo, i will repost.

mtierney5

robbie7730 wrote: »

It will be a servo similar to the winch ones you mentioned in a geared drive id say, something like this, might not be too bad on the AA`s but the C ones are not a bad idea.

The only thing about the 27 mhz is prone to interference from other radio control cars other kids might be using, Other than that it will work fine. Can try it anyway,

I'll leave it up to you about the batteries but im living out in the country so interference should not be a problem...

Bruthal

It will be a servo similar to the winch ones you mentioned in a geared drive id say, something like this,


Might not be too bad on the AA`s but the C ones are not a bad idea.

The only thing about the 27 mhz is prone to interference from other radio control cars other kids might be using, Other than that it will work fine. Can try it anyway,

Bruthal

mtierney5 wrote: »

I'll leave it up to you about the batteries but im living out in the country so interference should not be a problem...

Thats grand so, sure you can try it and see how it works, where will you be operating it, on a driveway at house? The ride on tractors and cars get better battery performance etc on hard surfaces than on grass for example.

Bruthal

coolwings wrote: »

Should be fine.
But if you put in one of those big high torque servos, they really suck power, so the little 4 x AA battery box for the blue receiver will have to be bumped up in size to a 4 x C cell battery.

The really big powerful servos i first linked have a seperate lead on them to connect to 12 lead acid batteries, i have never seen them myself, id say they would turn a real tractor.

mtierney5

robbie7730 wrote: »

Thats grand so, sure you can try it and see how it works, where will you be operating it, on a driveway at house? The ride on tractors and cars get better battery performance etc on hard surfaces than on grass for example.

ya tarmac and footpaths mainly, maye on the lawn a bit too.... battery permitting i suppose!

Bruthal

mtierney5 wrote: »

ya tarmac and footpaths mainly, maye on the lawn a bit too.... battery permitting i suppose!

yes it will run on the lawn alright, just better battery run time on the tarmac, easier on the drive motors etc, next you will be attaching a mower to the back of it and control it from livin room:D

mtierney5

now theres an idea!!!!

Bruthal

coolwings wrote: »

Should be fine.

Do you think them hitec digital servos etc will work properly with the 27mhz radio. Im not certain on that one myself.

coolwings

No problem.
The signal coming from the receiver is the same for both types.

Bruthal

Would be interesting project anyway. The forward and reverse in the tractor is done electrically as well so if a 4 or 5 channel radio was used, the stick normally used for rudder could be rewired into a 3 position switch on the radio to give 3 positions on a servo to operate the forward 2 speeds and reverse on the tractor too.

Bruthal

The tractor is here anyway, you probably got my email. The 2 speeds are done by swapping the 2 drive motors from parallel to series connected when the gear stick is moved. So we can do that with the radio controlled switches if i can get relays up to the job (30amp dpdt relays) if you want the 2 speed setup on the radio oand another switch can control another relay to reverse the polarity to the motors. Should be interesting.

Bruthal

Here is the progress on the tractor conversion to RC.

https://www.youtube.com/watch?v=bZLcRTeU2eI

Control circuit designed for tractor modification




Wiring temporarily in to do quick test


Relays temporarily in place to test radio control.

coolwings

Good work!

Steering next I presume?

Bruthal

coolwings wrote: »

Steering next I presume?

Yes its working out well, modified the circuit a couple of times so all seems well with it now so its steering next alright,
The original forward-reverse and 2 speed is done with a special switch which the gear stick is attached to, so it was just a matter of
coming up with a way of doing it with relays, 12v car relays i used. 40 amp contacts in them. Ideal.

I will use a servo setup like the one in post #21, should work well with that as its a powerful one.

Bruthal

The dx5e radio will need a slight mod as well, i will put a 3 position switch onto it for the reverse-forward-forward speed2 selection. The 5th channel on it only has a 2 position selector. Probably use the elevator pot wiring onto the 3 position switch as elevator control stick wont be needed for the tractor.

Bruthal

Update to tractor RC conversion

https://www.youtube.com/watch?v=vOkWQXm-Pqw

syl77

Well done Robbie...
You will need to add traction control though

Bruthal

syl77 wrote: »

Well done Robbie...
You will need to add traction control though

Yes the lad sitting on it might help with that:)

It actually drives exactly as it would out of the box, except car relays now switching on the motors instead of the foot pedal.

coolwings

That's a good job Robbie. A sort of one-off project.
I'll bet you enjoyed figuring it out.

Bruthal

coolwings wrote: »

That's a good job Robbie. A sort of one-off project.
I'll bet you enjoyed figuring it out.

Yes it was an interesting one alright, just about done now, just put some fuses in to protect control circuit, and a relay so if the 5v power to the radio receiver is lost the tractor will stop. And tidy up the temporary wiring.

It was some crack converting the steering servo to have a potentiometer outside it instead of the one inside it (external pot goes on the big gear of the gear box as seen in post #21), i burnt out the voltage regulator when tested the servo. At first i thought it was the servo motor because i had a gear inside the servo not sitting right when i re-assembled it which jammed it. All working well now though.

Bruthal

syl77 wrote: »

Well done Robbie...
You will need to add traction control though

Now you have me thinking. I might incorporate a brushed speed controller as well, for variable throttle, instead of the 2 fixed speeds it came with, but still have the 2 speed selection too for high and low. And see what happens.

Bruthal

Here it is with a brushed motor speed controller added to the setup. Just about finished now after receiving the steering servo etc last week.

https://www.youtube.com/watch?v=44O0be0-_mA

DublinDilbert

That's excellent well done. the speed controller seems to give it a nice gentle start too. It sounds like its re-gening the motor too which is good.

Top notch!

coolwings

It looks much better with the variable throttle.

Bruthal

coolwings wrote: »

It looks much better with the variable throttle.

Yes the way i had it is the same way they come, 2 fixed speeds using series-parallel switching of the 2 motors on back wheels. I still have that but now with the brushed speed controller. So it has variable speed and dual speed. With 2 motors in series for lower speed, the motor on each back wheel acts like an electrical differential, slow one wheel and the other speeds up. So the low speed setting is better for manouvering etc.

I might post some photos of the steering setup later today.

mtierney5

One Happy Boy!!!

mtierney5

I'll try and get a video up later!

Thanks again Robbie, your a legend!!!

mtierney5

http://www.youtube.com/watch?v=qFUf0VsfysQ

Plug

mtierney5 wrote: »

http://www.youtube.com/watch?v=qFUf0VsfysQ

He's loving it, fair play to Robbie for sorting it out. Now to hitch up the lawnmower on to the back of it!

Bruthal

Photos of the steering servo and linkages setup used for the tractor.

fergal.b

mtierney5 wrote: »

http://www.youtube.com/watch?v=qFUf0VsfysQ

Great job he looks to be enjoying himself, I also have a disabled son and is just learning to use a joystick for a motorised wheelchair, it might be worth thinking about adding one for your son and let him drive and you could take over if he get's into trouble , he seems to have a lot more movement and awareness than my son and it would be a great way to get him started.
Best of luck.

mtierney5

fergal.b wrote: »

Great job he looks to be enjoying himself, I also have a disabled son and is just learning to use a joystick for a motorised wheelchair, it might be worth thinking about adding one for your son and let him drive and you could take over if he get's into trouble , he seems to have a lot more movement and awareness than my son and it would be a great way to get him started.
Best of luck.

Oh ya! Never thought of that! Ummmm.... Oh robbie.....