Tutorials/Arduino Projects/RC car Hacking Project/Selecting a car
Size of the RC Car
RC cars can come in all kinds of sizes, from ones that can fit in your pocket, to ones that are a couple of feet long. The size of the RC car is an important factor since you will be trying to fit an Arduino and sensors onto the vehicle. However, bigger vehicles will require a larger driving area.
Small Vehicles (1/36th to 1/24 scale)
- Tend to be cheaper
- Require less power for the drive motor
- Requires only a small driving area
- Much harder to find places to mount all the electronics
- The smaller drive motors have a smaller amount of extra weight they can handle
- Less durable
- Some use a capacitor instead of a battery.
- Some of the cars use about 3 volts, but the Arduino needs 5 or 6+. So they would need an extra battery pack.
Medium Vehicles (1/24th to 1/18th scale)
- Can still be relatively cheap
- moderate durability
- have a fair amount or places to mount the Arduino and sensors
- can handle a moderate amount of extra weight
- tend to still need an extra battery pack to power the Arduino
- the body and the frame are often a close fit, so you might not be able to keep the body on after adding the Arduino
Large Vehicles (1/18th scale and up)
- no end to the places you can place the electronics
- can carry the most extra weight
- almost always uses 4+ AA batteries or a 6+ volt rechargeable battery pack so there is no need to add an extra battery pack
- fairly durable
- cost more than the smaller vehicles
- require a large driving area
- requires that the electronics can handle more power to control the vehicle than the smaller ones.
While you might be thinking that the price of the RC vehicle does not matter, it really does. If the vehicle is really cheap for the size, then it will be made from cheaper components. This means that it could be less durable, or the drive mechanisms are not ideal. However, if the RC vehicle is more expensive, you might be a little more hesitant to start messing around with it. Although the more expensive the more likely that the vehicle will have quality components and be well made and designed making the modifications easier.
Basically, while it is possible to convert a vehicle of any price, we recommend that the price be between $20 and $45 for vehicles that use regular batteries. We also recommend looking at vehicles that cost up to about $60 since you are more likely to find ones with rechargeable battery packs when they cost a little more. And besides, when you could go through 4-10 batteries every 30-100 minutes, the rechargeable battery packs start to sound really good.
Just like with any vehicle a person drives, the wheels and tires of the RC vehicle are important. A good number of RC vehicles are made with plastic wheels to save some money. The proiblem with plastic wheels is that the have very low friction on just about every surface. While this might not matter if you are just playing around with it as a toy, the low friction means that the the wheels will tend to spin and slide. this is a problem for a robot, since it is designed to expect predictable reactions, and the spinning and sliding of plastic wheels is not predictable. For this reason we recommend staying away from the plastic wheels.
Also, when selecting a vehicle, keep in mind that smaller wheels will tend to spin/slip more when accelerating/breaking. However this will be fairly consistent, so it can usually be adjusted for.
Just like with real vehicles, RC vehicles come in many types.
A conventional car design is a very safe choice for the RC vehicle. This design has a fairly boxy shape making sensor mounting easy. Additionally, Since the wheels tend to be covered by the body, there is less of a chance of the wheels or vehicle getting caught up on something while driving. The boxy shape also means that mounting the Arduino and other electronics inside the body should be fairly easy.
We recommend that for your first attempt at this project you go with a conventional vehicle.
The "Off-Road" truck design ........
There are lots of unique RC vehicles that don't fit into the above design types. Due to the vast quantity, and differences between these designs, we must recommend that you avoid these types of vehicles, unless you have some experience for doing this project before.