Live soccer robots on LMR
September 8, 2010
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.
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
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.
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 :(
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.