Introducing Rover R13

In this video I would like to introduce you to my latest robot that you can drive in my RoboSpatium. It is now the 13th vehicle that I have designed for my robot room - the name is therefore simply: R13. I had printed the parts of the mechanics in course of my review video of the Creality CR-10V2 3D printer. The largest component is the chassis with the dimensions 55x110x41mm - it is a very compact rover. I got the electronic components from my sponsor Gearbest.

00:46 - These are two small geared stepper motors including the driver boards,… …a step-down converter that delivers 5V output voltage at up to 2A, with a pack of buffer batteries… …a Raspberry Pi camera module,… …a micro servo for panning the camera,… …and a couple of parts for lighting as well as an infrared interface. A Raspberry Pi is used as the central “brain” of the vehicle. I use an older model B + with a wireless USB stick.

01:24 - The DC voltage converter must be set to 5V output voltage with the potentiometer before it is connected to the Raspberry Pi. The electronic components look like this when wired up: Energy is supplied by a 12V DC voltage source, being reduced to 5V by the DC converter needed for the servo, the motors and the Raspberry Pi. The ULN2003 driver chips have a total of 7 inputs and outputs, of which only 4 are required for motor control. On one of the two boards I use the three free outputs to control the headlight LEDs. The two motors can rotate counterclockwise,… …as well as clockwise,… …and the angle of the servo lever can be varied.

02:22 - The LEDs can be switched on and off in groups of two. The printed parts form the skeleton of the rover - if you look closely, you can see that I have redesigned and added a few parts in course of the assembly. The stepper motors drive the two front wheels, the rear wheels are rotated via the chains. With that the rover can move forward… …and backwards… …and turn on the spot whenever the two motors are driven in opposite directions. The robot is not really fast, which minimizes the risk of damage during operation - the kinetic energy of moving objects increases quadratically with speed.

03:20 - With the micro servo the camera can point up… … or down. The LEDs illuminate the dark areas of my robot room. With the help of the infrared interface, the rover can communicate with interactive modules in my RoboSpatium - here an Arduino Uno serves as a receiver that switches LEDs. Power is supplied via two sliding contacts, each of which connects to a metal grid - one for ground and one for the positive supply voltage. The one on the bottom of the rover is pressed on the power grid by gravity,… …

while the second terminal on top of the vehicle is biased by a spring. The system may be familiar to visitors of amusement parks. Caused by the sliding contacts there are short interruptions in the supply circuit. Since this inevitably causes the Raspberry Pi to crash, I use a backup battery pack consisting of nickel-metal hydride cells. Four of these cells deliver an output voltage between 4.0 and 5.2V, depending on the state of charge.

04:39 - The battery pack is connected in parallel to the output of the 5V DC converter and it is therefore kept at this voltage level. Before connecting the buffer battery for the first time, make sure that its output voltage is not significantly above 5V, as this could destroy the Raspberry Pi. Whenever the power supply via the sliding contacts is interrupted, the Raspberry Pi is powered by the batteries. With the help of a GPIO pin, the Raspberry Pi can determine whether the current flow through the sliding contacts is interrupted. If this is the case, the rover moves a little forward or backward until the current starts flowing again via the sliding contacts.

05:25 - In this state, the buffer batteries are recharged to 5.0V. Thanks to this power supply system, several robots can be operated in parallel in one room. The rover shown here will get companions over time. Next I have to install metal grids on the floor and ceiling of a part of my RoboSpatium. As soon as everything is prepared, I will show you in detail how to control my rovers. In the meantime, the robot is supplied with power in a traditional way via two cables, so that you can start first test drives. The build instructions including the 3D files created in OpenSCAD and the circuit diagram are already available on my pages. If you would like to support me in my efforts to expand my RoboSpatium and keep the rovers going, you can click the “Donate” button on my pages - many thanks to all existing supporters. Thanks for watching and: “I’ll be back!” .