Raspberry Pi RC Car

Hello Faizan,

What you need is:

• A motor controller. Car motors should not be directly driven by the raspberry.
• A communication method. The easier is bluettoth, so a bluetooth dongle for your Pi.
• The software on the Pi and on the Phone.
• Optionally you can buy an already made chassis with motors.

There are plenty of motor controller board out there to control the motor. Usually an H-Bridge IC to control the movement of the motor in both directions as you will want your car to have reverse.

One of the cheapest and easiest controller I used on the Pi, is the Ryantek controller https://www.ryanteck.ltd.uk/rtk-000-001/ but it requires some easy soldering. If you don't want to solder any H-BRidge DC motor control board will work. I use to work with L298 based like this one https://www.sparkfun.com/products/9670 because they are sturdy and can use them in other projects with high voltages up to 35V.

The bluetooth dongle must be compatible with the Raspberry so take a look at here before to buy one. RPi USB Bluetooth adapters - eLinux.org

The software on the Phone won't be that hard to build but it will depend on your programming.

I know for Android there are already made bluetooth robot controllers you can just download and configure like this https://play.google.com/store/apps/details?id=pl.mobilerobots.vacuumcleanerrobot

I don't know if there is something similar for iPhone but I would look for it before to start to code.

The software on the Pi will depend a lot on the motor controller to use but usually is just to pulse some pins for direction and two PWM channels for speed.

The chassis is optional, you can just screw everything motors and that on a thin board and it will be ok.

Not long ago we had to made 10 cars for some robotic classes and we found good enough to buy cheap chinesse chassis like those Arduino Chassis: Electrical & Test Equipment | eBay but there are plenty of them there out like Magician Chassis: Amazon.com: Industrial & Scientific or a little better ones like Pololu - Dagu Rover 5 Tracked Chassis with Encoders or many others. You even have beasts like https://www.sparkfun.com/products/11056 if you fancy it but I would not spend that much on a chasis.

The only thing to look on those chassis is they have motors, battery holders and some kind of screw in system so you don't need to drill holes on it.

Take a look at this and if you have more doubts don't hesitate to come back and ask.

I'd agree with most of this parts list except really these days with the WIFI been like £2-3 for the little USB units  you may as well use themt and really writing a simple program to stream data or control some I/O is much easier over a more conventional network link after all you can do this using an apache webserver on the vehicle and a browser rather than dealing with the specifics of bluetooth!

I agree with the wifi part, specially if you want to stream video, because it's much easier to set it up on a web server.

But overall I prefer bluetooth over wifi for robotics because wifi eats lots of juice and drains batteries quite quick.

To overcome the main problems related to bluetooth - so many protocols - I use mostly blutooth as a virtual serial port - must be an RFCOMM protocol capable device - so I just read and write the /dev/ttyUSBX block device to comunicate over bluetooth. That works even with the other MCUs like AVR (or arduino) where you can use a bluetooth to serial like https://www.adafruit.com/products/1588 (there are much cheaper ones in the market) and just use the UART pins for comunication.

Anyway wifi is fine. Much better if you want to stream video.

But take care with the energy requirements of the wifi devices you use. A friend of mine got a wifi camera - NetCam Wi-Fi Camera with Night Vision - to attach it to a Dagu chasis for a "Mars Explorer" Robot, and it ended up draining 3A just for the camera. At the end the LiPo batteries was almost as big as the robot for just a couple of hours of fun.

That won't be a problem in this case with the Raspberry Camera and a wifi dongle though.

I agree with the wifi part, specially if you want to stream video, because it's much easier to set it up on a web server.

But overall I prefer bluetooth over wifi for robotics because wifi eats lots of juice and drains batteries quite quick.

To overcome the main problems related to bluetooth - so many protocols - I use mostly blutooth as a virtual serial port - must be an RFCOMM protocol capable device - so I just read and write the /dev/ttyUSBX block device to comunicate over bluetooth. That works even with the other MCUs like AVR (or arduino) where you can use a bluetooth to serial like https://www.adafruit.com/products/1588 (there are much cheaper ones in the market) and just use the UART pins for comunication.

Anyway wifi is fine. Much better if you want to stream video.

But take care with the energy requirements of the wifi devices you use. A friend of mine got a wifi camera - NetCam Wi-Fi Camera with Night Vision - to attach it to a Dagu chasis for a "Mars Explorer" Robot, and it ended up draining 3A just for the camera. At the end the LiPo batteries was almost as big as the robot for just a couple of hours of fun.

That won't be a problem in this case with the Raspberry Camera and a wifi dongle though.