• Asus WL-500GP router
• Atmel Atmega48 microcontrolle
• 3x FAN 8082 electric motor drivers
• LM2940T voltage regulator
• 1x SG-5010 servos
• 3x AS-170 servos (Don’t buy them, they more or less self distruct if the arm somehow gets stuck!)
• 4x Sanyo 2500mAh NiMh rechargeable batteries
• Phillips SPC200NC webcam
• Tamiya Track and Wheel set
• 2x Tamiya Double gearbox
• 5x white LEDs
• Different electric components as resistors, capacitors and wires

So, how is OVR working?

Let’s start with the basics. How the hell do we power all these components? The router is powered from the original power adapter, so we need a plug. In the near future, we want to power it from 6 NiMh cells, using a switching power supply (the voltage needs to be very near 5 V all the time). The webcam is powered by the USB port of the router. Everything else is powered by the 4 rechargeable batteries. The servos and the motors are connected directly, electronic components are connected trough the voltage regulator and some filtering capacitors.

Now, how are commands sent? The router runs the OpenWRT Linux distribution and the WiFi card is enabled. There are two daemons running on it: spcaserv for streaming the video from the webcam, and our program (written in C), used for remote controlling. The router gets the commands via a TCP socket. How the hell can it move the motors? Well, that’s the microcontroller’s job. The microcontroller runs a program written by me in BASCOM AVR and it receives the commands from the router using the serial port. It generates a PWM signal for the servos, and uses the FAN drivers for the electric motors moving the tracks and for the LEDs mounted on the webcam.

What do we use the servos for? One AS-170 moves the webcam (and the LED’s) up and down. SG-5010 moves the lower part of the arm. Another AS-170 creates an articulation at the middle of the arm. The last AS-170 is used for grabbing stuff.

First, I should mention some commands the robot knows about:

• forward,right,left,back,stop - for movement
• ledon,ledoff - for light control
• numbers from 1 to 32 - for arm’s first servo (the one on the robot)
• numbers from 65 to 96 - for arm’s 2nd servo (the one in the middle)
• numbers from 33 to 64 - for the arm’s 3rd servo (the one controlling the hook)
• numbers from 97 to 128 - for the camera’s servo (for moving the camera up and down)

I should mention that the numbers are positions, and changing the state of a servo from one limit to another takes about 0.2-0.4 seconds.

Here you have the (very bugged) source in AutoIT. Copy the text and try to compile it. The robot movements should work. Everything is released under GPL, so you can do anything you want with the code, but please, mention somewhere where did you take it from (Open Video Robot - http://wifibot.linux-geek.org)

ovr_control_source

Later, the Linux’s controller code - in QT

From Dreamline moment, we made some modifications to it, which greatly improved the opinion of the people about it:

1. Robotic arm, with 3 servos. It can move (not turning aroung yet, but may be), pick up stuff and leave it in another place. Or push up the robot, in order to jump over some things in front of it
2. 5 LEDs over the webcam. In Ankara, someone asked how does the robot work in the night. Then it was kind of impossible. Not it is ok - the LEDs in a complete dark room allows you even to read a book
3. Software improvements - not it doesn’t stuck so often, and it has better control

In the following days I am planning to put here all the source-codes we have, and the protocol we use to control it. After that, my teammate will explain in some steps what he did in order to build all the electronic part.

Until then, some posts containing infos & photos from Infomatrix Contest (in Romanian)

1. Infomatrix 2008
2. Medalia de aur la Infomatrix 2008 (Gold medal at Infomatrix 2008)
3. Medialie de aur la Infomatrix (Gold medal at infomatrix)
4. Infomatrix 2008 - poze de la ceremonie (Ceremony photos)
5. Infomatrix 2008 - Pe scurte (Briefly)
6. Articol in ziarul Gandul: Robotul spion al elevilor romani (Article in “Gandul” newspaper: The spy robot of the Romanian pupils)
7. Medalie de aur la Infomatrix 2008 (By Cosmin)
   

Even we had a few problems (so we needed also cable power input beside the batteries), everything was fine, and we got a Jury’s special prize. Meaning diplomas, medals, and some money:D More or less, it is wonderful for a beginning. Now we started to think about some improvements we can bring to the robot, in order to make it really the best platform.

Below you can find some documents we presented at Ankara (.pdf, .ppt and some posters)

• Robot full documentation - .pdf file
• Open Video Robot presentation - .ppt file (the text is 90% taken from the .pdf)
• Poster 1
• Poster 2
• Flyer (the interior, which actually contains information)

The Open Video Robot is a different view over the classic idea of a mini-vehicle with one or more
video cameras on it. This device is basically built from a wireless router (Asus WL500G), on which
special devices are connected in order to perform different tasks: a webcam for getting the images,
and some electric motors to make the device move. Everything is kept as simple as possible, in
order to make the device easier to understand, maintain and use.

So that is different about this device? The price (4-5 times lower than usual moving remote control robots), and the architecture, which built on a standard wireless router, is as open as possible to any type of modification.