13. Lighting up the Robot

A major part of the modern electronic devices glamour comes from the calm inhuman glow of the LED's carefully embedded into their bodies.

Our robot is not an exception. Adding just couple simple LEDs, changed its appearance radically. Let's see what resources the robotics designers can tap into, and bring more light into their projects.

11. Infrared Distance Sensors

How it works

Facing the insufficiency of the ultrasonic distance sensors for the autonomous navigation, we arrived at the next stop - infrared distance sensors.

The plan was to build kind of sensors array formed by the numerous distance sensors facing in different directions and saving the robot at least from hitting the obstacles in front and falling down from the height. These sensors must be inexpensive both in terms of money and energy consumption.

Soon we found an interesting option, surprisingly named "Infrared Obstacle Avoidance Sensor for Arduino Robot" - it is precisely what we need!

10. Ultrasonic Distance Sensor

How it works

It is time to teach our robot navigating autonomously around the room. Some time ago we installed Ultrasonic Distance Sensor HC-SR04 with the mounting bracket. But up to this point, it was used just as a nice decoration.

9. WiFi Remote Control

Finally, we found some time to play with the ESP13 board. After a deeper investigation - this module proved to be a very self-sustaining and robust shield which grants the limitless access to the WiFi connection for any Arduino projects.

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.

4. Arduino MEGA 2560

WHY?

The grandiosity of the plans we have for our mighty robot raised some concerns. Can a single Arduino UNO carry on all the tasks we expect? At that time we did not trust much the wires-saving technologies like I2C or SPI. So we thought, first of all, we will quickly run out of available Arduino ports.

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).