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|Target Environment||Locomotion Method|
|Sensors / Input Devices||Actuators / Output Devices|
|IR proximity detectors||Modified Futaba S3003 servos
|Control Method||Power Source|
|CPU Type||Operating System|
|Time to build||Cost to build|
|URL for more information|
|This is my first attempt to build a robot. It is based on
Basic Stamp IISX and modified Futaba S3003 servos. The only
electronics on the board except for the Stamp is a more
powerful power supply, built from a 7805 and two capacitors.
There is also a 9 pin connector + two small capacitors to
connect to the PC and a resistor + LED showing if theres is
power or not. I also put a reset button on the board.
The robot has two IR LEDs and corresponding IR-detectors on separate boards. The Stamp is driven by a small 9V battery, and the servos by 6V NiCad batteries mounted under the chassi. The rear wheel is a table-tennis ball.
The most expensive part was the Stamp and the cost was about 120$.
It has no real purpose, the only thing it tries to do is to run forward and avoid obstacles.
The first problem I had, ( now resolved ) was that as soon as the servos started to draw current, the Stamp would reset and start the program from the start.
I have found three solutions to that problem. One is to have separate power supplies for the Stamp and the sevo. It works find but the Stamp II SX takes about 60mA so the 9V supplies gets drained quite fast.
The other solution is to have one power supply at 6 or 7.2 V and a BIG capacitor ( I use 4,7 mF ). That works fine too, and I prefer to have only one ( rechargable ) power supply. The second solution is what I use now. There is a third solution is to use a switched power supply, much like what the cellular phones use. That allows the stamp to run longer tnan the servos. I also had some timing problems with the IR-detectors since the Baisc Stamp IISX is about 2.5 times faster then the Basic Stamp II, and I forgot to adjust the program for that in the beginning.
Greetings Mats Ínnerby ( Sweden )