Let's Make Robots!

Live soccer robots on LMR

Recently Gareth suggested to me that it would be good to have 2 teams of my bi-ped robots playing soccer. This was too good an idea to ignore.

After talking about this idea backstage this is where we are at:

On behalf of DAGU I will donate 6 Mini-Biped robots (plus spare parts) and an Arduino compatible IR transmitter to control them. Frits has volunteered to host the robot soccer match. Players would control the robots from their homes via the internet and the video would be streamed on LMR so the players can see what their robot is doing.

What we need is someone who can write some simple software to be loaded on the player and host computers.
The software for the the players will take keyboard commands (e.g. Cursor keys and spacebar) and send this information via the Internet to the host PC.
The software for the host computer (preferably mac compatible) will receive the data from the 6 player computers and send it to the Arduino compatible transmitter as serial data.
The data only needs to be a simple code such as the number 1-6 indicating which player has pressed a key followed by a letter A-E indicating which key was pressed.
A = forward       
B = backward
C = left
D = right
E = stop / kick
Thus the data stream would be something like 0D1A2A3E4D5C etc.
These robots are small, slow and clumsy so while the game will not be fast and furious I hope it will be fun to watch as well as to play.



Below is an explanation of how I will be programming the Arduino transmitter which will receive serial data from the host computer the same as it would using the serial monitor built into the Arduino enviroment. The Host computer will simply pass on the data it receives from the players computers.

Because the IR receiver needs to receive at least 14 pulses at 38KHz to recognise a 1, the Sony protocol uses 600uS as the width of a data bit and 1200uS as the width of the start bit. These times could be shortened but that could reduce reliability so for now I will stick with them. Beyond that I am ditching the Sony protocol which has 7 data bits and 5 device bits for a shorter, faster protocol.

I will write the Arduino code to send out 1 start bit, 3 player ID bits and 3 command bits. This will allow a maximum of 8 player and 8 commands. For now we will only have 6 players and 5 commands.

The Arduino will poll the player IDs thus the first 3 ID bits will count 0-5 repeatedly. The command sent out will be the last command received for that robot.

Each robot will be programmed with it's own ID so for example when the code 1A is sent out, all robots will receive the code but only robot 1 will respond and walk forward.

Because the slow IR transmission presents a bottle neck to the flow of data it would probably be best if the program running on the players computers limited the rate it sent command to 10 commands per seccond. This is fast enough to ensure a reasonable response time but will prevent the Arduino serial buffer from overflowing.

7 lovely red robot brains sitting on my desk. The main PCB is a simple little Arduino compatible board. The smaller PCB at the back is his "backpack" with speaker and IR comms hardware. An IR compound eye plugs into the front. I should have 7 little robots on their way to Frit's house next week. The seventh is a spare, just in case.

I've dubbed them the 7 dwarfs.
Here are some links to video of the prototype so you can get an idea what their soccer skill are like :P

RC chasing a ball: http://v.youku.com/v_show/id_XMTg0NDMxNTY4.html

Autonomous goal keeper: http://v.youku.com/v_show/id_XMTk5NDY1MTcy.html

Update: 20-09-2010

I have upgraded the Game Transmitter hardware and software to allow the pan/tilt assemblies to fire lasers (or other weapons) at the players. Lets be honest, no robot competition is complete without laser fire!

I have attached the code for both the game transmitter and the soccerbots. Currently the soccerbots will accept commands from both the game transmitter and a TV remote. The TV remote allows the host (Frits) to calibrate and test the players without a computer. The players ID can also be entered by TV remote so that if a player dies during a match Frits can quicky replace it with the spare robot just by changing the spare robots player ID to that of the dead robot.

Calibration settings and player ID are stored in the robots EEPROM so that the data isn't lost when the robot is turned off.

Update: 22-09-2010

As the famous saying goes, the devil is in the details! The seven dwarfs are not accepting commands from the game transmitter. As they work fine from the TV remote I have to assume the problem is with the transmitter. On the oscilloscope the transmitter seems to work fine with a nice modulated 38KHz signal.

Until I can sort this problem out the Dwarfs are staying in China :(



Update: 22-01-2011

Well they are finally in Frits's workshop. If nothing else Frits will learn a bit about Arduino. I did a lot of last minute stuff before I sent it all out and forgot the ball in the process. Now I need to get some instructions together for Frits.

I've taken some of Frits's photos and labelled them so every one knows what all the thingys are.

The Mini-Bipeds are normally sold pre-programmed for use by younger robot enthusiest. Therefore a programming cable was not produced. As Frits's will probably need to update the code a few times I quickly made up a cable. Experienced users can make a serial cable quite easily or use the ISP socket.


Soccerbot_transmitter_V2.zip2.35 KB
Soccerbot_V1.zip3.7 KB

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Hi, we should talk details of the hardware.  Can you send your Skype through my contact here? Does Skype work through China?  What mode of communication would you suggest? Right now, I would like to know:

  • What Arduino (model) are you using for the infrared transmitter?
  • What shield?
  • What code - is there any currently?  Do you need that? - I have a little "slave" program for the Arduino - which basically turns it into a slave of the computer.  It would take very little to add a Serial Write function which just does the relay or translation or whatever you need to go out onto the IR.  If we use it I can use the same Arduino to control the cameras etc.


In theory I think skype can work in China, in practice the last few times I've tried going to the site to download the software I've been re-directed to a page of adds. I keep checking the computer for spyware and other infections but it always comes up clean.

The Arduino used in this case will be another Mini Biped processor board with a USB interface and a custom IR backpack to make sure it can cover a wide angle. The processor board has 4 servo outputs so it could control 2 pan/tilt kits if neccessary.

The code will be super simple:

1. Read in two bytes of serial data and verify that a number and letter were received e.g. 2A (player 2 walk forward).
2. If the player ID is a camera then read aditional bytes for pan/tilt and adjust servo outputs.
3. If the player ID is a player then transmit via the IR LEDs 1 start bit (1200uS), 3 player ID bits and 3 command bits.

I will post the code when I have time to write it (I'll try and do it tonight as the dwarfs should be finished by then). There will probably need to be some error checking involved and depending on how the data comes in from your host software there may be additional code for translating or sorting. 

I will email you with my messenger contact details.

Here's what Wikipedia says: http://en.wikipedia.org/wiki/Skype#Service_in_People.27s_Republic_of_China Quote: "Since September 2007, users in China trying to download the Skype software have been redirected to the site of TOM, a joint venture between a Chinese wireless operator and Skype, from which a modified Chinese version can be downloaded. The TOM client participates in China's system of Internet censorship, monitoring text messages between Skype users in China as well as messages exchanged with users outside the country." Some Skype forum posts like this also claim that TOM-Skype and some malware, trojans and ads with it. So I wouldn't install that on my computer.

I hope you can get good old original Skype working there.


Hey, Oddbot. I've used Skype in China, though it was back 3-4 years ago. I had the software installed on my computer prior to arriving in China. So the download may be a problem, but it will probably run OK. Maybe someone can send you the install files in a zip archive.

Yes, I think that will probably solve my problem as I believe MarkusB uses Skype in China.

Let me know what OS you run, and I can send a file.

Neither the latest or the greatest but it runs my software and has been fairly well behaved.

We'll finally meet voice to voice ... sweet...!

Can you get/make another pan/tilt servo mount for the overview / top camera (Ooooh or maybe a gantry cam !!!! - I don't have continuous Servo interface for the software - but i wanna make one) 

1 Arduino will be controlling the 7 bots through a serial write through some shield  - 1 pin

2 pwm pins for a field camera with pan&tilt  & 2 pwm for the gantry cam !

Sound about right?

If we run out of inputs/ouputs or crap to attach - the software is extensible in that multiple Arduino's can be controlled.  And if I or Chris ever get done with the PicAxe interface you can start hanging them off of your computer too.

Everything will be attached !

Resistance is Futile !

You will be Assimilated !

For the public record; Grog and I had a good Skype on the above :)

I understood 50% of what he said, in 4 miliseconds.

I will send Frit's a pan/tilt kit as well to mount a web cam on.

Perhaps this could be remotely controlled as well? It would be like an extra player except the servos would be directly controlled from the Arduino clone rather than IR.