MR - 4 : Robotic Tank

thingiverse

My latest tankbot has been designed to be a larger vehicle that is easily printable on even a small scale printer. You can see it in action here: https://youtu.be/KUup3ndVikM. Several key issues with previous tanks have been overcome (hopefully) with this one. I've made some updates since the initial release. UPDATE 1: I've modified the COG - please use V4 to resolve track catch issue. The catch issue is much more pronounced when printed in PLA than ABS. UPDATE 2: Two new track variations have been added, allowing for adjustments based on materials, print settings and printer type. My own printer and ABS work fine with the standard track, while my printer and PLA need a combination of the 2.2 and 2.4 track types. The number refers to the center diameter of the pin hole, ensuring enough tension in the track while still allowing for free movement. First and foremost, it now runs on two standard-sized continuous rotation servos, which can be obtained with various torque settings to suit your needs! Secondly, the tracks are specifically designed to be joined using 1.75mm filament offcuts, eliminating the need for expensive stainless steel rods and saving time by not requiring glue. Thirdly, I've designed it to bolt together rather than being glued - this makes changing parts or reconfiguring it possible. Some notes and hints: The tank should fit a range of standard-sized servos (although they're not all that "standard"), but you may need to adjust the square spindle to fit your servo nicely into the cog. I like to over-power my robots in terms of battery - my video example has 12V - and then use a step-down power converter to power the servos, which means longer drive time, more power and less chance of your controller (Arduino) resetting due to the servos stealing all of the juice. I've designed several different body configurations. Feel free to experiment with whatever suits your needs. So far, I've only designed an external Arduino Uno mount, but you could run it on any controller that suits. This tankbot was specifically designed for my Up! Plus, but a fault occurred halfway through the design phase and I finished it on a ProJet full-color powder printer that I have access to. You can still print it in and FDM printer greater than 100mm x 100mm. The body section with the built-in sensor is designed for an HC-SR04 ultrasonic sensor and the Adafruit RGB Color Sensor. *The body section with provision for the 12V battery clip (which takes 8 x AA batteries) also has provision for a 16mm round press switch.* You will need 26 tracks per side - note that you should print the tracks without supports, otherwise the pin holes may clog up and require drilling out. A 2mm drill bit does this nicely. The source files can be accessed here: https://drive.google.com/open?id=0B0oR8i_t-zjyVnRWb1hxeUlPRlE. Print Settings: Printer Brand: Up! Printer: Up Plus Rafts: Yes Supports: Yes Resolution: 0.2mm Infill: 50% Notes: The body parts can be tricky to print, but I get the best results by printing them on their side and then treating them with a quick acetone vapor bath (not heated) to prevent splitting. I also recommend printing the tracks without supports.