14. Radio-controlled Robot

The new challenges

We consider our tank-robot project as a very successful one - our creature can be nicely controlled remotely over Wi-Fi, or navigate around in the autonomous mode avoiding dangers and collisions. Still, there are questions which we could not answer:

• Remote control over the Wi-Fi lags even if you connect your agents directly. Is there any better way to control the robot? Can the Radio Controlling system be the answer?
• Do you really need to purchase expensive factory-made chassis, or there is some better way?
• Could LCD displays be useful for a small robot?
• Is it hard to use Li-Ion battery in the project?

To answer these questions - we decided to build a new robot, which will be a lightweight peer for our tank.

6. Power for the Robot

The fіrst prototype

While working with the introductory Arduino experiments, it is unlikely you face any concerns on how to power your circuits. Usually, your board receives all it need through the USB connection from the computer. For the sophisticated experiments you can even buy a breadboard with the power supply module (like this one).

Talking about the autonomous robot - it starts to be a bit more complicated. You can't rely on external power, and you need to find the way to have everything on board.

5. Operating the Electric Motors

Transistor-based DC Motor Control

The best way to work with the DC motors is to use a specialized Motor Shield.

At first - we did not have it. But still, we were desperately eager to try our new chassis in action.

We were lucky - while building our starting kit, we took a couple of NPN transistors 2N2222A. Here and here we found a nice and short explanation how to use a transistor to control high currents of the DC motors without the risk to damage the Arduino board.

3. Chassis Selection

The Plan

Preparation steps may take a lot of time. I and my son spent more than two months learning the basics and running small experiments with Arduino. We used a custom-built starting kit, passed a couple of beginners ramp-up courses, played with Arduino board, sensors, LED and electric motors driven by transistors. Ultimately, we figured out what can we expect from the Arduino-based robot, and what kind of the tasks it can perform.

We decided to build a rather big robot which should be able to wander around the rooms. It needs to be capable going over 5 cm (2 inches)  doorsteps (because that is the height of the doorsteps in our house. Also, the robot must be stable and capable of wearing lots of sensors, a video camera or a cell phone, and/or some small TFT screen. Imagination instantly paints some caterpillar-chassis robot 10 cm high and 20x20 cm long and wide (~4x8x8 inches).