What is Geeros ?

Geeros is a self-balancing robot open and customizable, very appreciated in STEM courses. The heart of the robot is the Arduino compatible “Romeo” board, made by DFRobot.

This board is very interesting because it is fully compatible with an Arduino Uno and it also includes a dual DC Motor controller and 3 pins (Vcc, GND, Signal) for each I/O.

You don't need any more to use an additional prototyping board due to the lack of Vcc and GND pins, as it occurs currently with classic Arduino boards.

Geeros also includes:

• 2 DC motors 6V with 34:1 gear ratio and 48 CPR quadrature encoder. Nominal speed at 6V: 185 rpm
• integrated 3 axes accelerometer and gyroscope (IMU) with I2C interface (Invensense MPU6050)
• 7.4V Lipo 2200mAh battery with integrated protection and charging circuit: you just need a standard 12V, 1A adapter (supplied with the robot) to charge it
• a Linux (OpenWRT) board with integrated Wifi (for remote control with a computer or a smartphone) and data telemetry. By default, Geeros is a standalone access point and doesn't need any Wifi router box to communicate with
• a Webcam for real-time video transmission (through a mjpg-streamer server running on the robot)
• a servo-motor for tilt control of the Webcam (movement in the vertical plane)

Geeros is open: all the sources of the Arduino sketches are provided. You can modify them as you like or create other ones to re-program the robot (the program loaded by default in the delivered robot allows him to keep the equilibrium and to be remote controlled by a computer, a smartphone or a tablet).

The Linux board is fully reconfigurable, you have a full root access to it via SSH (either through Ethernet, Wifi or even serial console).

By default, it features:

• fully configurable OpenWrt Linux distribution, with by default:
• LuCI for Wifi and network properties modification
• a Web server (source code of the Web application files for remote control are open, you can easily modify them)
• a FTP server
• a SSH server
• a mjpg-streamer server for real-time video transmission
• a telemetry server for data coming from the Arduino

Why did I made Geeros ?

Usually, students use in STEM courses hardware based on industrial products. Despite the effort dedicated companies make to instrument these hardware (in order to get measurements on them), the products remain not very open.

Geeros has been created so that students and teachers can work on a fully open robot: they can see the different elements inside and how they are connected together. They can explore the source code, understand how it works and why this self-balancing robot doesn't fall.

They can add sensors and modify the source code in order to integrate these new sensors. The only limit is the imagination and the physical possibilities of the robot (it will never run at 10 km/h !).

How does it work ?

Geeros keeps its equilibrium thanks to its sensors (accelerometer, gyroscope and quadrature encoders) and to the software executed in the micro-controller. Everything is explained in the Arduino sketch and in the documentation.

Getting started with Geeros is easy:

• put it on the floor
• switch it on
• if it lays on its front, it will start automatically. If it lays on its back, you have to put it manually at a vertical position (Geeros on its back is the safe rest position)
• connect to the Wifi network "Geeros"
• open your Web browser (from a computer, smartphone or tablet) at the IP address http://192.168.0.199
• you can then drive Geeros with a virtual joystick (from your computer) or using the orientation of you smartphone or tablet.

What can I do with Geeros ?

First, you can play with it !

But you can do also more serious things because Geeros is an open platform you can use to work on its different subsystems:

• You can drive the robot, get measurements from the Wifi connexion and display them with our telemetry application. Then, you can analyze and/or make computations on these data
• You can study the voltage control of the DC motors (the Arduino sketch and the GUI are provided). You will see that in this open-loop case, when you give the same voltage to the 2 motors, they will turn at 2 different speeds. Not very different, but enough to understand that speed control is necessary in order to have the same speed on the 2 motors
• You can then study the speed control of the DC motors (the Arduino sketch and the GUI are provided). You can even modify the gains of the PID controller while the motors are running through the GUI ! You will see directly the effect of the 3 gains on the control performances
• You can display in real-time the 3D orientation of the IMU.
• You can add some sensors (a proximity sensor, for example, if you want to make an obstacle avoidance robot): attach the sensor on the prototyping plate, connect it on the Romeo board, modify the Arduino sketch to handle this new sensor
• You can modify whatever you want on the Linux board (full root SSH access through serial console, Ethernet or Wifi)

What will I get when I buy Geeros ?

When you buy Geeros, you will get hardware, software and documentation.

Hardware:

• Geeros itself, of course !
• 1 x USB A-B cable for Romeo board programming
• 1 x 12V, 1A power supply
• 1 x allen key for the wheels (if you want to remove them, but the robot is not very interesting without wheels…)
• 2 ball casters: some of our customers asked for them, in order to make experiments without vertical control. These ball casters are easy to mount on the robot, if you need them also

Software: you will be able to download the following items:

• additional Arduino libraries to have your programs to compile properly
• Arduino sketches:
• Full sketch for Geeros control as a self-balancing robot
• Voltage control of the DC motors
• Speed control of the DC motors
• Display of IMU data
• Corresponding GUI applications (see the screen shots in the image gallery)
• Telemetry
• Voltage control
• Speed control
• 3D visualization of the IMU orientation

Documentation: you will be able to download the following items:

• Full documentation of the robot and its different applications
• Developer documentation (explains the different ways to communicate with the Linux board)
• Equations of the robot

You can choose between 2 language versions for the software and the documentation: french or english.