Need help with motorized car

Hi!

I'm trying to build a 4-wheeled car that runs with one motor. No steering, just moving forward. It should be operated with remote control or two push buttons like this:

Button 1 = Makes the car just move (and stop) slowly forward continuously. Speed control with potentiometer.
Button 2 = Makes the car move very small amounts smoothly per pressing the button. Range should be controllable with potentiometer or similar.

Movements should be very smooth and slow, plus the whole device weights around 3kg so the motor should be strong enough. I'm a cnc machinery guy so the mechanical parts are piece of cake, but I just can't understand the electronics at all. I bought an Arduino Uno starter kit but got stucked very shortly after blinking leds lol.

I wish someone here could give me a "small" push into the right direction. What components I need, is it too hard for super newbie to build it without months of studying, and last backup question how much should I pay for someone to make me bolt on -electronics? :slight_smile: Any help highly appreciated!!!

Unfortunately, there isn't enough info in your post, and what there is - is hard to understand.

What motors are they?
What power source are you using?
For a 3kg payload, you're probably going to need a power driver interface, unless the gearing is so low that the motor current is negligible.

Button 1 makes the car move forward and stop continuously...?! go-stop-go Jerking?
Button 2 makes it move small amounts? One movement per press?
Smooth and slow is neither of the above.
Slow/car speed is a function of the motor speed and gearing.

Let's solve the local pushbutton scenario first, then worry about remote later.
What happens if the car hits an obstacle?

That's all to start, there will be many more questions later.
Is this a one-off project, or going into production?
Perhaps some application background will reveal some other options.

I think you should build and program a small proof-of-concept robot.

To drive two wheels with one motor you could use something like this motor/gearbox and screw it to a plywood base. Size in plan view would be about an A5 sheet say, whatever's needed for the power train and (say) an Uno and a breadboard.

That would let you get the logic of the thing clear in your mind, without initially having to worry about the current and voltage matters that will arise when you try to accelerate 3kg.

lastchancename:
Unfortunately, there isn't enough info in your post, and what there is - is hard to understand.

What motors are they?
What power source are you using?
For a 3kg payload, you're probably going to need a power driver interface, unless the gearing is so low that the motor current is negligible.

Button 1 makes the car move forward and stop continuously...?! go-stop-go Jerking?
Button 2 makes it move small amounts? One movement per press?
Smooth and slow is neither of the above.
Slow/car speed is a function of the motor speed and gearing.

Let's solve the local pushbutton scenario first, then worry about remote later.
What happens if the car hits an obstacle?

That's all to start, there will be many more questions later.
Is this a one-off project, or going into production?
Perhaps some application background will reveal some other options.

Thanks for fast responsing guys. Sorry about bad details, english is not my native language plus I don't know what I need to ask so this is a bit tricky.

I don't have any motors yet. I don't know should I buy servo, stepper, or dc motor with gearbox. Car should stay in it's position when it's not moving, and even better if there was some fade in and out when it start moving and stops because of the heavy load.

I have no powersource neither. Something that can move this baby for like 10mins would be perfect.

Button 1 = Push it once and car starts to move. Push it again and the car stops. Speed controlling with potentiometer.
Button 2 = Push it once and car moves one movement and stops. Push it again and it move again the same amount. Range control with potentiometer. (around 1-100mm range)

It's hard to estimate the final moving speeds, but maybe from worm's top speed -> walking duck is fine :slight_smile: I'll make the transmissions when I have working prototype in hands. Car doesn't hit anything, no need to worry about it. This is not really a car or toy but similar platform with four wheels so I'll call it a car. I think after first working unit I make these 20pcs more, no more plans about production.

ok, that explanation is a much better start.

Simple low-cost geared DC motors would do for your project, and won't need much power to push 3kg since it's all on wheels (unless you're going uphill!)

You will need a motor driver of some sort... this could be a simple MOSFET, or an H-bridge if you need to reverse the direction.

Battery and 10 mins isn't too much... probably a separate 'grunty' battery for the motors, and smaller for the Arduino & logic - due to spikes created by starting and stopping the motors frequently. Motor/gearing and runtime will be the biggest single factor to select the propulsion battery.

The code to drive this is pretty insignificant for an experienced developer, but you need to create something that physically meets your requirement - then we can help massage the code to fit.

Hi,

An electric window motor for a car (local junkyard?) would be a nice 12V DC geared-down motor.

A power NFET like THIS: could control it from an Arduino digital output used as PWM (Pulse Width Modulaton). See the Arduino analogWrite command HERE:

IF you need to reverse the motor the simplest way is to use two relays like THESE:

Poor diagram!

Start with some info HERE:

DISCLAIMER: Mentioned stuff from my own shop...

lastchancename:
the Arduino & logic - due to spikes created by starting and stopping the motors frequently. Motor/gearing and runtime will be the biggest single factor to select the propulsion battery.

The code to drive this is pretty insignificant for an experienced developer, but you need to create something that physically meets your requirement - then we can help massage the code to fit.

Yes 3kg isn't very much, and all moving parts have ball bearings. No need to go uphill, or reverse.

Does this kind of motor look like correct?

I have many Samsung INR18650-25R batteries, can I use 4pcs of them for the motor, and 2pcs for Arduino?

Do I need this kind of shield too?

And the rest of the parts, I have Arduino Uno but what else do I need? Maybe some bluetooth or IR receiver too if it's not super hard to build remote control. Gears etc mechanical stuff I can make myself.

terryking228:
Hi,

An electric window motor for a car (local junkyard?) would be a nice 12V DC geared-down motor.

A power NFET like THIS: could control it from an Arduino digital output used as PWM (Pulse Width Modulaton). See the Arduino analogWrite command HERE:

IF you need to reverse the motor the simplest way is to use two relays like THESE:

Poor diagram!

Start with some info HERE:

DISCLAIMER: Mentioned stuff from my own shop...

Hi Terry and many thanks for response! I'll try to study these stuff as well. :slight_smile:

This is sooo hard my head explodes in any minute. I followed your tips, watched another 50 youtube videos and found some small bits all around the web, but didn't really understand much :o
Get ready to laugh, here is the amazing wiring diagram below!

(Transistor is what Terry suggested )
Have no idea is there anything right. As you see the tactile's wires are missing, I didn't figure out where to put them. Do I need some another components for switches or potentiometers?

aa51:
As you see the tactile’s wires are missing, I didn’t figure out where to put them.

Switches can be wired in any of the 3 ways shown. The use of the internal pull-up is the easiest.

pullups and pulldowns snip.JPG

You need a current limiting resistor to protect the Arduino pin on the gate, as shown.

resistor on gate.JPG

You need to connect the motor power ground (ie the 12V -ve) to the Arduino ground.

You may also like to add a couple of small caps between the wiper of each pot (+), and ground (-), to damp out any low-level jitter in the analog value being read. Pretty much anything between 0.1uF and 4.7uF will help.

And just noticed (because I have exactly the same error on my bench as we speak) there’s no flyback diode.

flyback.JPG

Some progressing, found the arduino starter kit and also fritzing software.
Here is my present wiring, I think it's better start with one push button and potentiometer.
Should I do something for it before continue? Here is the fritzing .fzz file of that image.

I also found many example codes, but not any helpful. I can't get the potentiometer work with push button. With only potentiometer it works, and with only push button the motor spins. Any suggestions?
HERE is my code. With this code the push button works like a charm, motor spins and stops and no sparks anywhere!