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### Topic: Power Wheels Modification - Selecting a Motor Driver for Arduino (Read 94 times)previous topic - next topic

#### thedoctor4ever

##### Mar 19, 2019, 10:14 pm
Hi everyone - I've been working with robotics for the past few months to learn the basics of electronics, and how to use a microcontroller to control motors.

I am currently working on modifying the electronics in a Power Wheels ride-on car to make an autonomous vehicle; an ultrasonic distance sensor will send signals to an Arduino Uno, which will then regulate motor speed and direction. I've worked with small motor drivers in the past, but for this project, I will need to use something much bigger.

Currently, I am planning on using the two 12V DC motors that came with the Power Wheels car, and wiring them into a motor driver that I will use with the Arduino. The main goal I have is autonomous movement of just the vehicle, but I may attempt to modify the electronics so they can successfully move a passenger in the car forwards. As of right now, I'm planning on using a 24v18 Arduino motor shield from Pololu, which can continually deliver 18 A of current to each channel. I've included the link to the driver below:

https://www.pololu.com/product/2518

Is there any way I can determine how much weight this motor and driver combination can move, or at what speed? I would use a 12V SLA battery as a power supply for the shield and motors, and would expect this vehicle to drive mainly on flat, level ground. If I decide to include a passenger, I may have to upgrade the existing motors and power supply to 24 Volts - could I use a similar Pololu motor shield to achieve this? I'm unsure if this motor shield would meet the current requirements of my motors.

Thank you very much for taking the time to help me as I start exploring more complex motor drivers - it really means a lot to me!

#### shooter

#1
##### Mar 19, 2019, 10:58 pm
for a wheelchair about 10 kgf is needed so about 100 Newton force to move meaning 100 watt .
so calcs about double the force needed is 200 watt for the motors. in 24 Volts meaning about 10 amps.
paul deelen
shooter@home.nl
making controls with codesys PLC and arduino

#### JCA79B

#2
##### Mar 20, 2019, 03:29 am
Lots of unknown variables there, expected top speed, acceleration (how much time to get to that speed), mass, gear ratio between motor & wheel, wheel diameter, motor torque, full load current, stall current, etc. etc. Can you post a link to motor datasheet or sellers web page?
The most intelligent people in the world are the ones who don't think of themselves as the most intelligent person in the world.

#### thedoctor4ever

#3
##### Mar 20, 2019, 05:47 pm
Sure - I've found the link to the motor data sheet, and posted it below:

https://disti-assets.s3.amazonaws.com/testco-inc/files/datasheets/16794.pdf

From what I could find, I can also fill in a few of those unknown variables:

Wheel Diameter - 13 inches
Gear Ratio - 138:1
Expected Top Speed will probably be somewhere around 3-4 mph

Acceleration will be handled by Arduino PWM, so I'm uncertain about what it will look like yet.

Mass - Ideally, I'd like to be able to transport a person in this vehicle, making the total weight of the car + passenger somewhere around 180-200 pounds. The car itself will likely be around 40 pounds including batteries.

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