ROSCO - Track Rover
by mpluma, published
RO bot SCO ut - Small (relatively) Arduino Powered rover featuring 1-piece Printed ABS treads.
New Thing: http://www.thingiverse.com/thing:145577
New Design Utilizes Android 3.0+ Device for Camera/Wi-Fi Remote control (Telepresence)
More Details at http://www.Arxterra.com
Design intended to incorporate DC motors (propulsion), servos (for look up/down), and stepper motor (for look left/right), IR sensors (distance ranging), laser pointer (for coolness), shaft encoders (for speed detection/DC motor syncing), gyroscope (for automated missions), XBee control (for guided missions), and a mini-video camera (for coolness).
I designed this as part of a school project, replacing a purchased metal chassis/kit with a fully 3D printed (as much as possible) body kit.
Suggestions for Improvement Welcome.
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Print out a Chassis, a set of wheels, some treads and add a lot of vitamins.
PART LIST (links to my sources to come)
1x Arduino Uno (or Mega, but you'll have to drill some holes and shuffle some pin assignments, but you won't need the NANO)
1x Arduino NANO (unless you use a Mega)
1x Adafruit Motor Sheild
2x DC motor w 90ÃÂÃÂ° gearbox
1x stepper motor
1x Dagu Mini Pan & Tilt kit
1x 700mAH 7.2V NiCd battery
1x charger for NiCd battery
1x battery adapter for NiCd
2x shaft encoders
2x Tiny Breadboard
2x rechargeable 9V battery
1x Charger for 9V battery
2x battery clip for 9V
2x right angle barrel connector (center +) for 9V ->arduino/camera
2x DPDT mini switch
4x 1x6 female header
2x 1x8 female header
1x 16 pin IC socket
M3x8 hex socket screws
M3x16 hex socket screws
Breadboard jumper wires
2x 2N2222 NPN BJT transistors
2x 22K resistor
2x 4.7K resistor
2x 1K resistor
2x 10uF capacitor (polarized)
2x 47nF capacitor
2x 10nF capacitor
1x Long Range IR sensor
1x Midrange IR Sensor
1X Laser pointer
1x Current Sensor
2x XBee modules
1x XBee USB side
1x XBee Robot Side
1x mini camera w/ receiver
2x clip-on heatsinks
1x extra h-bridge
1x extra 595 shift register
2x extra shaft encoders
2x 1x8 Thru pin female headers
2x 1x6 Thru pin female headers
Assembly instructions for the printed parts to come. I /am/ still in classes right now. This bot is for one of them and we still haven't got all of the systems working smoothly yet.
This piece is likely to be one of the longest, most arduous, heartbreaking prints you'll ever do. I'm working on a design that will decrease the print time but this version is anywhere from 10 hours (.33mm layer height on my prusa2) up to 17 hours (.2 layer height on my machine). Because it's such a large plate, I suggest having your bed be a little warmer (I set mine to 62C for PLA) and print at a slower speed (all my Slic3r speed settings set to ~30mm/sec, travel @130mm/sec). I also have to print without any skirts on my 185x180 print area. My next chassis design may be just a bit smaller to make it easier to print.
The braces (2x brace B and 1x brace C) screw to the underside of the chassis and add some rigidity. They also hold the larger motor battery in place on the underside.
It's probably a good idea to print all four wheels at once. They fit nicely on my print area. The DC motors connect to the front wheels via the "Drive Wheel Adapter". The adapter attaches to the inside of the wheel prior to attaching the wheel to the DC motor.
The back wheels use the shaft of the shaft encoder as an axle. If you don't want to use shaft encoders you can use any 6mm dia. bolt/rod as an axle but you may have to round out the hole in the wheel. The set screw should hold the wheel to the axle either way.
If the wheels wobble as they turn it's okay as long as they wobble too much and the treads fall off. It's only happened once so far to me, but adjusting the wheels fixes it.
IT IS VERY IMPORTANT TO PRINT THE TRACK USING ABS. PLA won't work. I tried. It's not flexible enough. I made a test using the original track (http://www.thingiverse.com/thing:15528) using PLA but it broke after playing with it for less than half an hour. ABS is super bendy and it really takes an effort to make it fail. I've been running on the same set of treads for a few hours a week since early February. They still have their flex and snap.
The treads should be slightly narrower than the grooved section of the wheels.
All the other prints are pretty straight forward. I even included some sample gcodes that I used to print the parts in the appropriate sets. The gcodes are sliced at .33mm layer height at a moderate speed that seems to work for all of our printers here at school.
Remember, FURTHER ASSEMBLY INSTRUCTIONS TO COME