It is designed for anyone wishing to turn on the welder and start swapping with wires, motors and batteries to build a small robot to show to friends or math teacher. It does not have to be a source of stress in particular, but of fun.

Electronics can be a banal way to enjoy, learn and do something concrete, requires manual and enthusiasm. It takes a lot of effort, but satisfaction and fun cost you a lot of fatigue.

The minirobot consists of 6 parts:

- a base (frame)

- the swinging wheel

- wheels with wheels

- power supply and power switches (on / off);

- engine control

- Contact sensors

The built minirobot will be able to "navigate" in an environment, changing direction when encountering an obstacle.

Chassis: dimensions that depend on the type of engines and wheels we can procure. So before we buy engines and wheels, then we build the base. To build the frame you can use the material you like: wood, plastic, plywood, metal, etc. In DIY shops, drilled metal pieces of approx. 3 mm are solded. This makes them very robust and durable, but at the same time heavy and difficult to perform. In contrast, paperboard is definitely not recommended.

It is important that the structure is solid and therefore the exact height of the oscillating wheel, the position of the motors and the diameter of the wheels must be positioned so that the minirobot is perfectly flat.

If you are desperate, take a plastic or wooden box, turn and use as a chassis, positioning motors and batteries inside and making two holes to get out of the engine shafts and stick the wheels.

For the swivel wheel: The third wheel can easily be purchased with little money at a bricolage store. These are the wheels that are used for trolleys, armchairs, tables, etc. They are called "rotating wheels" because the rotation axis can rotate 360 ° around the vertical axis.

As an alternative to tilting wheels, we can use spheres, though they tend to block, perhaps because of dust particles entering and causing friction, and for this I feel disapproved about their use. However, balls are also found in bricolage stores.

Engines must be equipped with gears. In fact, gear changes the engine speed in power, allowing the load to be transported (batteries, circuit and frame itself).

We can buy engines already equipped with gears: there are very expensive and cheap ones (less than $ 10). An even cheaper system is to disassemble old toys and recover small engines and wheels.

We choose wheels with wheels so we can not fix the wheels on the pins. Even the wheels could be made with old cdroms: the important thing is that the wheels are firmly attached to the pivot of the motors!

Batteries

It depends on the type of engines you have mounted on the minirobot. If we use 6 volt motors, we must use a 6 volt power supply that can be obtained with four 1.5 V (1.5 x 4 = 6) batteries. To hold the batteries together, you can use battery compartments: some may think that you can use rechargeable batteries, which are now easily available in supermarkets as well. In this case, please note that each rechargeable battery provides 1.2 volt and if you need 6 volt you need 5 (1.2 x 5 = 6) and not 4 as for "normal" (non-rechargeable batteries ).

Be careful to secure the battery in a "comfortable" place so you can easily change the batteries when they are discharged. If we have space, we can fix it under the minirobot so that it does not touch and do not stick to it.

Switch

It needs to turn on and turn off the robot. We use any type of switch: sledge, lever, button etc. The switch must also be fixed to a place where it is easy to use, to turn on and turn off the minirobot.

The switch must be connected to the battery in series to interrupt the positive wire: remember that the positive (+) is indicated by the red color and the negative (-) of the black color. We use this colors to prevent you from confusing.