Let's Make Robots!


i am trying to make a 2-wheel drive car but can't get a propultion motor (motor to push it front or back) to drive it either it's too weak, it's too heavyor it's too powerful! please help!!!!!!

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Well my friend, several of us have tried to help you, but you won't make it easy. We ask for clear details of your whole set up, and we get partial answers that are not always clear. I am officially done trying unless I see some real effort on your part to provide information that has been asked for, such as:

  • Clear, in focus pictures of your set up
  • Circuit diagrams of how everything is connected
  • Details about your compents (e.g., a link to where you got your motors, so we know what you have)

I'm glad you have come to LMR, but you must learn how to ask for help in a useful way.

You are still making us guess a lot about your setup. Please provide as much info as you can. Include clear, in focus pictures, diagrams, and circuit schematics if possible.

What sort of batteries are you using? Are they fully charged?

Does the motor turn if you connect it directly to the battery?

It sounds like you are hacking an RC toy car? Which one?

I'm confused about your statement that you are using the RC circuit to control the car, and the L293D to drive it. Please explain in detail how your project is powered, controlled, etc.

You will get better answers more quickly if you provide this level of detail when you first ask your question. We have no idea what you are starting with. We only know what you tell us, so tell us as much as you can.

i'm using a lead-acid battery of 12 volts 1.2 amps. Actually i'm hell scared of micro controlers (cause of the programing) all i did was short the enable pins en1 and en2 with + 5volts and gave the input pins the current that would normaly go to the motors by the way the motor turns everythings spining but when it on the ground it just stops (the structure of the model is based on a car propultion system (the pics can't put cause my comps bust a bit).i'm douting its the torque that might be less. 

How heavy is this 12V lead acid battery? BTW, I think you probably mean that your battery is rated at 1.2 Ah (that's amp-hours). I imaging that weighs at least a couple of pounds. Perhaps your robot weighs too much for your motors to move it.

I still feel like we have to pull each little bit of information from you. Could you describe your project in detail? I know you said your computer is busted and you cannot post pictures, but you could provide better written information.

For example, please tell us:

  • What motors are you using? (free running current and stall current)
  • How much does your robot weigh?
  • Which microcontroller do you intend to use?
  • How do you have your L293D motor driver connected?
  • What gauge wire are you using?
  • How is everything connected?

We've asked some of this before.

i'm using a normal motor (i think it's free runing , robot weighs 2kg, no microcontrolers in sight, just a direct connection to the input pins i shorted the enable pins, the motor driver and the r/c circuit has different power source

is still looking for more information from you.

1. What is the current draw of the motors?

2. A schematic of how you have the 293 wired up.(If you are using one you found on the web, then post a link to it at the very least)

3. What gauge wire are you using? If your wire is too small you could have problems getting enough current to your motors to drive them

4. A schematic of how you have the rest of your circuit wired, in case something you have wired up is causing problems.

my motor draws 9 mili amps at no load while i've used wires from a computer power box ofr the motor and i connected the input pins to the r/c out put wires iam running the ic by the lead acid battery.

i have used geared motors for it and i'm using a r/c car circuit to control it. while i've used l293d to drive it


Do these motors have any kind of gear attached to them or do they go straight to the wheels?

i've used geared motors and a r/c car circuit for control. while to drive it i'm using l293d