m4tt
03-03-2008, 08:14 PM
http://members.shaw.ca/freedumb/robot.jpg
Here is a picture of my current robot in progress. The chassis is based off of a Team Associated Monster GT 4.6 SE R/C monster truck. I got bored with the nitro engine in it (too noisy) plus the ridiculous price for R/C nitro fuel (~$40/gallon here). I'm basically building it with stuff sitting around my work area, minus a few of the navigation sensors.
The heart of this beast is an 18V drill motor. Even though I am only going to be running it off of a 12V lead acid battery, there is still enough power to spin the tires on carpet when I hold it by the back bumper. The motor mount is extremely "expedient", basically just a hunk of aluminum bar and two pipe clamps, bolted to the aluminum frame of the truck. The motor is coupled to the transmission using a sprocket I found inside of the drills gearbox. I decided to leave the original transmission on because it is really rugged and provides two forward speeds (not sure if the rev's will go high enough to get to second gear though), as well as easy reversing and braking features controlled by a servo. Speed control will be done with a MOSFET salvaged from the original drill controller, interfaced to a microcontroller.
The brain will be a PIC18F4520. I have sensors such as a Devantech TPA81 thermal detector array, a Maxbotix ultrasonic rangefinder, and I plan on eventually getting a GPS module and a bunch of infrared close range proximity detectors to encircle the robot with; angled down ~45 degrees to detect obstacles on all sides and any extreme drop offs. I also have millions of servos to put sensors on to allow panning/tilting. All of the circuitry/sensors will be mounted on the converted-purpose tool box tray, I may or may not adapt the original body to fit over top of this - aesthetics aren't really a concern of mine (in case you can't tell by the picture).
To begin with I am planning to program the robot to slowly (but autonomously) follow forest trails/logging roads with no extreme terrain. I plan to use the thermal array sensor on a servo to detect "organic" obstacles, such as trees and plants which should be a bit different temperature than the ambient air. The sonar module will supplement this, allowing the detection of obstacles heatsunk by the earth (such as rocks). After this I will work on making it go from "point A to point B" in more extreme terrain, navigating around obstacles and such.
Just thought I would post this here in hopes of possibly inspiring others, and to have some neat ideas thrown at me for possible features I should add or anything useful this robot can accomplish.
If anyone is interested I can post some code I wrote for controlling up to 8 servos with the pic (written in C, tried to use the least amount of on-chip resources possible). I wasted too much time looking for pre-written code and finally decided to write my own, if this is useful to anyone let me know.
Here is a picture of my current robot in progress. The chassis is based off of a Team Associated Monster GT 4.6 SE R/C monster truck. I got bored with the nitro engine in it (too noisy) plus the ridiculous price for R/C nitro fuel (~$40/gallon here). I'm basically building it with stuff sitting around my work area, minus a few of the navigation sensors.
The heart of this beast is an 18V drill motor. Even though I am only going to be running it off of a 12V lead acid battery, there is still enough power to spin the tires on carpet when I hold it by the back bumper. The motor mount is extremely "expedient", basically just a hunk of aluminum bar and two pipe clamps, bolted to the aluminum frame of the truck. The motor is coupled to the transmission using a sprocket I found inside of the drills gearbox. I decided to leave the original transmission on because it is really rugged and provides two forward speeds (not sure if the rev's will go high enough to get to second gear though), as well as easy reversing and braking features controlled by a servo. Speed control will be done with a MOSFET salvaged from the original drill controller, interfaced to a microcontroller.
The brain will be a PIC18F4520. I have sensors such as a Devantech TPA81 thermal detector array, a Maxbotix ultrasonic rangefinder, and I plan on eventually getting a GPS module and a bunch of infrared close range proximity detectors to encircle the robot with; angled down ~45 degrees to detect obstacles on all sides and any extreme drop offs. I also have millions of servos to put sensors on to allow panning/tilting. All of the circuitry/sensors will be mounted on the converted-purpose tool box tray, I may or may not adapt the original body to fit over top of this - aesthetics aren't really a concern of mine (in case you can't tell by the picture).
To begin with I am planning to program the robot to slowly (but autonomously) follow forest trails/logging roads with no extreme terrain. I plan to use the thermal array sensor on a servo to detect "organic" obstacles, such as trees and plants which should be a bit different temperature than the ambient air. The sonar module will supplement this, allowing the detection of obstacles heatsunk by the earth (such as rocks). After this I will work on making it go from "point A to point B" in more extreme terrain, navigating around obstacles and such.
Just thought I would post this here in hopes of possibly inspiring others, and to have some neat ideas thrown at me for possible features I should add or anything useful this robot can accomplish.
If anyone is interested I can post some code I wrote for controlling up to 8 servos with the pic (written in C, tried to use the least amount of on-chip resources possible). I wasted too much time looking for pre-written code and finally decided to write my own, if this is useful to anyone let me know.