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Overview
This is a simple 4/5 servo robot arm. It is controlled by a vb.net app which sends out data over rs232 to a PIC.
The PIC then positions the servo to a position between 0 and 240. This version features gradual servo movement, and can support upto 12 servos in parallel.
This bot uses my BotBoard |
Software
VB.net 2008 application. This app is using the code base from the GunBot.
For this bot I needed another axis on a joystick. I have a Logitech game pad that was ideal for this. The left thumb pad drives the motion servos, and the right thumbstick moves the turret. 2 buttons are used to control the servo that opertates the light, one for on, the other for off.
The new addition to this app is the motion code. It uses a tri-wheel setup, so the 2 main wheels do the driving, while a 3rd wheel adds stability. To go forward, I tell one servo to go forward and one to go backward. As they are mounded opposing each other, this makes both wheels move forward. To go left I tell both to go the same way, one wheel turns one way, the other turns the other way.
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Construction
This arm uses a total of 3 servos:
- 1 large (Futaba S3003 360 degree mod): Drive Left
- 1 large (Futaba S3003 360 degree mod): Drive Right
- 1 mini (eSky): Light switch
- 1 mini (eSky): Pan
- 1 mini (eSky): Tilt
I managed to locate some perfect material for making robot chassis. A local sign maker had some 3 and 5mm mounting board. It is dirt cheap, strong, sandable and cuts easily. I should also say that super glue loves it and gives a very very stong bond :-)
I havd to modify a couple of Futaba servos to make them run continuisly. This is an easy mod and only works with servos with plastic potentiometers (the cheap ones). There are some good vids on youtube to do this mod. A chassis was easily made up from this sign board, servos fitted, wheels attached and other components such as the rs232 port and switches were fitted. The pan and tilt mount is made from 3mm plasticard, as I had already built it for another project.
As this bot was mobile, I neede wireless rs232. I looked at modules to do this, but thought it far far easier just to get a bluetooh serial cable replacement adapter. It is easy to setup and works perfectly!
The cam on this bot is a mini 2.4Ghz colour wirless setup.
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Images
Here are the images relating to the project.
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