Monday, April 27, 2015
Actobotics Expert Challenge--Parts List
I'm participating in the Actobotics Expert Challenge , where five builders each gets $1,000 in parts to build a labor-saving or home automation machine. I just ordered my parts and when they come I'll do an unboxing, but here are some standouts:
Channel: Actobotics' signature element is the channel and I bought a bunch. I got a pair of 24-inchers just because; I didn't need them for my project. The chassis consists of mostly 18" and 9" channels, and I bought 4 and 7 of these, repectively. I got some channel mount gearboxes that use 3.75" channel legths if you don't have them in a bigger one, so I grabbed two of these. Finally, I'll be moving a platform with a belt and pulley, so I got a 1.5" channel length for the pulley.
Servos: I messed up and failed to buy a continuous rotation servo to move the belt, so I'll have to figure that out later. I made up for it buy buying the aforementioned channel mount servos, which are ridiculously expensive and probably more powerful than I really need. Pricewise, they're $125 each when you factor in servo programming and gearbox assembly.
I mentioned that I didn't buy a servo to turn the pulley. That is not 100% correct because I did spring for this rather sweet HS-646WP waterproof servo, has 161 oz-in of torque, and can be immersed up to 1 meter. The only probably is, the servo has only the stock 90 degrees of rotation and would need to be reprogrammed for continuous rotation. If I don't have time, I'll just buy an el-cheapo continuous rotation servo because the motor's robustness really doesn't matter that much in this application.
Bearings & Shafts: The platform the belt is connected to rolls on rather cool linear ball bearings with 8mm inner and 15mm outer dimensions. I got 8mm x 300mm shafts for them to run on, as well as clamping hubs for each end to secure them. Now that I write this, I think I may have forgotten to buy the hardware (presumably tube clamps) to attach the bearings to the platform. However, I may just end up 3D printing some.
Attachments: Part of my difficulty in choosing my parts was that I had a hard time visualizing how to attach things together. What sort of mount would I need for this element of the project? What kind of attachments do I need to bolt things together? Not being completely sure what I'd need, I got a whole bunch of screw plates, the attachment of choice for Actobotics. I got 10 large screw plates and 20 dual screw plates, plus 48 single screw plates. For screws I opted for Actobotics-standard 6-32 socket-head screws; I got 200 of these, all in .375". I have a bunch of other sizes already, but found myself always running short of the smaller screws, which is mostly what Actobotics uses.
I have a lot more observations to make about my order, but that's good for now! I'm excited to be a part of this fun contest.