How do you 'slow' a vehicle down?

[SpikeTop]

Hi guys,
Newbie here and needs a little help.
I bought a $19.95 RC 18 Wheeler from ebay and the controls are a bit hard to handle. The truck won't 'creep'. It either goes full speed ahead or reverse or not. How do I make this cheap RC truck creep along for backing up to a 'dock' as it were? Is there an inexpensive way to do it?
I'd appreciate any advice and suggestions you may have on the subject.

Thanks,
Spike

 

[machinehed]

Wire a diode and resistor to motor for reverse function

 

[Rolex]

Can't do it. It's a toy, not an RC truck. Full on or full off. I know the steering would be the same. Centered, then full left or full right, no in between.

 

[SpikeTop]

Can't do it. It's a toy, not an RC truck. Full on or full off. I know the steering would be the same. Centered, then full left or full right, no in between.

Yes, that's true. It's either full whatever or it isn't. Machinehed says I can. Now, who's right? Can I or can't I? Will a resister and diod do the trick?

Thanks

 

[Rolex]

Machinehed didn't understand your question and told you how to get reverse. You already have reverse. I've purchased 3 1/5 scale HummVees that worked the same way. All or nothing. Full left, full right, full forward, full reverse. I only bought them for the beautifully detailed bodies and then spent insane time custom building the chassis, suspension and drive systems. I'm at about $800 each after starting out with a $100 RC.
I added an electronic component to a helicopter to slow the retracting landing gear down to be more to scale, but that component alone cost more than your truck.
The cheap "Toy" grade RCs do not have any variable adjustments or individual servos that can be switched or upgraded. Sorry, but what you buy is what you get and there's nothing you can do with it.
Tamiya has several incredible tractor trailer rigs but you're at a thousand bucks with the full rig. It also needs a programmable radio.

 

[Tunedfrog]

Cool looking truck but unfortunately that's the down side of buying a toy versus a scale truck as mentioned above.

 

[machinehed]

Yes, that's true. It's either full whatever or it isn't. Machinehed says I can. Now, who's right? Can I or can't I? Will a resister and diod do the trick?

Thanks

When power is switched to reverse,electrical current flow can be controlled with a resistor,and the diode would prevent feedback of current when flowing in forward,,,any electrical flow may be manipulated,it is a matter of your ambition and imagination,even relays could be used,

 

[SpikeTop]

Yes, Rolex, you've described my toy very accurately twice now, so let's see how to mod it. I need input as to how and I won't take no for an answer. I've been modeling for decades and used to have one of the fastest slot cars on the track BUT it wasn't RC. I do know my way around the workbench. Now that I'm 72 years old and handicapped I don't get out much anymore and want this toy to creep around my tiny senior citizens apartment for enjoyment. I once drove across country for 3 years and loved it. That's why I bought this small 18 wheeler.
It also 'flys' down the hallway at about 90mph and when I turn it'll flip over. Talk about fast! I gotta slow this thing down, please.
I have an extra Syma X9s Flying Car and have been considering gutting it to put it in the truck.
So, how about looking at it positively and help me mod it to make it creep.

Thanks,
Spike

 

[machinehed]

Ok, take a diode place it side by side with a resistor,solder the ends together,place it inline in place of the power wire to the motor,power will travel at a resisted voltage to the motor in one direction,and when you switch to other function forward ,voltage will flow unresisted .it's a simple application,the thing you have to know is voltage from power source so that you can choose the proper rating of resistor, ie ,100K versus 500K, with 1watt rating,diode needs to be rated larger voltage than power source also.you need to find out which direction to place the diode and which lead to motor to place the diode and resistor also,use trial and error if needed,if truck goes slower in unintended direction,place diode and resistor on other lead to motor.if you want to slow down truck in both directions ,apply the same setup on the other power input lead to motor as well.if you want to make one direction slower than the other use a bigger ohm resistor, I will draw a diagram if needed , remember place this at motor lead ,also to test the speed for either direction just place different ohm resistor until you are happy with the speed ?

 

[SpikeTop]

OK, great. The truck uses 4 AA batteries while the transmitter uses only 2 AA batteries.
I don't really know much about electronics so will follow your lead. I did understand your post but don't know how big the resister and diode should be on 4 AA batteries?
There are two wires coming out of the battery box but if I patch in there I'll reduce the 6v power down to the whole circuit board. I don't think that's any good so I want to patch in to the rear motor leads, RIGHT?
There is a little round brown thingy that says, 104, on it across both motor leads. What is it? (Sure is a crappy solding job whoever did it)

 

[machinehed]

OK, great. The truck uses 4 AA batteries while the transmitter uses only 2 AA batteries.
I don't really know much about electronics so will follow your lead. I did understand your post but don't know how big the resister and diode should be on 4 AA batteries?
There are two wires coming out of the battery box but if I patch in there I'll reduce the 6v power down to the whole circuit board. I don't think that's any good so I want to patch in to the rear motor leads, RIGHT?
There is a little round brown thingy that says, 104, on it across both motor leads. What is it? (Sure is a crappy solding job whoever did it)

View attachment 120311

That is a capacitor,look at it like a micro battery,helps motor overcome startup power needed for motor .yes make connections at motor leads so only motor is affected by new circuit

 

[machinehed]

Any diodes and resistor rated for 1watt ,12 volt will work fine,

 

[SpikeTop]

OK, how big should the resistor and diode be if I'm running 4 AA batteries at 6 v? I have a multimeter and tested the voltage. I'd like to try about a 75% reduction in speed/power to the motor.
I like it to just crawl around the room.

 

[SpikeTop]

Can you suggest where I can buy electronic parts? Our Radio Shack went out of business a couple years ago.
Oh, shoot me your schematics on this idea, please.

 

[machinehed]

You can buy online or scavenge parts from an old radio etc.

 

[machinehed]

Not sure which way current flows for reverse function,turn diode around if needed

 

[machinehed]

Also,build same circuit on other side for slower but different speed,resistor changes speed.?

 

[SpikeTop]

Gotcha!
Thanks

 

[D3MON]

Also,build same circuit on other side for slower but different speed,resistor changes speed.?

i think you have one of your diodes backwards on that drawing, not to nit-pick but just for his install.
very interesting way to go about that. only thing though is that it will reduce speed, and still will be on/off type switch, just will be a slower on/off wont it?

 

[Rolex]

it will reduce speed, and still will be on/off type switch, just will be a slower on/off wont it?

That's correct. There is no way to set up a variable speed circuit for either the speed control or the steering with the stock circuit board and supplied transmitter.
@SpikeTop, I was also into slot cars but with those you were able to adjust the voltage going to the track with the hand held controller that was hard wired to your track. Good look with this project, I'll be following the build.