For making a robot selection of materials is very important sometimes this differentiates between winning and losing.
Following are the basic materials required to make a wired/wireless robot:
- Remote control set(only for a wireless robot)
- Material of Chassis
12V DC geared motors will be sufficient for most of the robots. Selection of speed (in rpm) depends on the competition. Speed also effects the torque of the motor. Generally for dc motors as speed increases torque decreases. This can be seen in the graph below.
So if the weight of the object the motor is attached to is less than you need a high rpm motor and if the motor is attached to a heavy object than a low rpm motor(high torque) motor is required.
As rpm of the motor increases the torque will decrease and ease of handling will also decrease.
Below are the suggested motor specification according to the required or event:
- Robot race- 500 rpm or 750 or 1000 rpm. If the race track consists of less number of turns than 750 or 1000 rpm motors will be better if it has many turns and complication 500 rpm motors will be suitable.
- All terrain Robot- 300 rpm
- Robot arm:- 10 0r 30 rpm
- Robot soccer-300 rpm if its individual competition, if its a one on one event use 200 and 300 rpm motors in the same robot
- Robot Sumo-60 o 100 rpm depending on the weight of the robot
Almost for all robotic competitions in India the voltage limit is 12 volts. So a lead acid rechargeable 12 v battery would be suitable.
If on the day of event your battery is low on charge you can connect this battery with many cells(its easier to get cells in techfests rather than a 12v battery) in parallel than the voltage wont increase but the speed at which your motors rotate will definitely increase.
REMOTE CONTROL SET:
Most of the techfests allow participants to use ready made remote control sets so it makes sense for you to buy a wireless remote control set rather than making one. You need to buy a RF dual frequency(both of them should be less than 56MHz) remote which can operate 6 devices(mostly motors).
In my first robot for a techfest i used a ready made chassis which was a big mistake since i was awarded -50 points for using a ready made chassis. So never buy a ready made chassis and always make your own.
For most of the events a chassis made of wood will be sufficient as operations such as drilling,hammering, polishing etc can be easily done in wood. If your robot is a flying robot than Balsa wood is th best choice