Thursday, November 6, 2014

MOARbots, the ESP8266, and more omniwheels

This project finally has a title.

MOARbots: Modular, Open-Source, Affordable Robots.

Progress on MOARbots is as follows:

I learned about the ESP8266 through Hackaday and decided to purchase a few. It is a $5 WiFi chip and programmable microcontroller to boot. I haven't been through the recently translated datasheet yet, but it seems to clock at 80MHz and have 16 GPIO pins, 2 of which are broken out on the boards I purchased. It will require tons of development to be usable for MOARbots but the community is very interested in it to make Internet of Things happen at a low cost point, so I won't be alone.

I decided to make a micromini version of my omniwheel bot, based around three Pololu motors I got for free. The motors are far too expensive at $15 to be part of the framework's suggested bill of materials, but for now this is a good project to test out my designs for small 3d printed omniwheels. I'm working through some designs, and here's a render of iteration #1.

Hand forming steel wire made sense for circles, but not squares. I didn't want to take the better part of a month to build a CNC wireformer type machine, or to bother making simpler hand jigs for preset sizes or shapes, so I've rethought the design and will aim to use small finishing nails, which are cheap and widely available and don't need to be formed.

After the monthly Sector 67 meeting, a few people test drove the 2-wheeled cart. Despite the very simplistic control scheme (pre-programmed forward, left, right, stop routines), users were able to drive the cart pretty smoothly, even getting interesting drifting action at top speeds. The battery was barely drained even after a solid 20 minutes of driving, and with the addition of a heat sink the L298 motor driver was doing just fine (the heat sink is very necessary though). So this iteration of the cart is a success I think, and I will just need to buy some more L298s before I have everything I need to assemble 6 more.

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