14 SERVO 09.2014
Q. I co-mentor a high school robotics team. We have previously done very well in the RoboCup Jr. Soccer competition with a four-wheel holonomic robot
of our own design. We used Transwheels from Kornylak
Code=FXA308) mounted to micro-gearmotors (Figure A).
This year, we are looking to make a more professional
looking robot (no hot glue!), but are having a hard time
finding a way to mount hubs to the wheels. Universal
mounting hubs from Pololu ( www.pololu.com/product/
1083) looked like an attractive option, but we haven’t
found a good way to mount them (Figure B).
Have any good suggestions?
A. Okay. This is probably the most asked about and most frustrating topic for folks making a rolling robot. Some kits come
with wheels already mated to hubs and specific
motors; sometimes you can find hubs that work
with your wheels and motors, and sometimes
(like this time) the wheel isn’t specifically for a
hub or a particular motor shaft (and the motor-hub-wheel is the gift that keeps on giving!). I
have to solve this with every new robot! So, here
is how I do it — and it usually works. I just have to be VERY
careful since I don’t have a fancy machine shop with lots of
cool tools (like a lathe to make custom hubs and fittings).
Figure 1 shows the motor, hub, and wheel that I am
going to mate. In this case, the hub is a custom one made
for a set of wheels that do not perform well on OSB board
wood surfaces. I decided that I wanted to try some R/C
sedan racing tires that I had good luck with on asphalt
The very first thing you need to do is find a substitute
shaft for your wheel and hub, and mount it somewhere. I
by Dennis Clark
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t’s amazing the sorts of projects that pop up around the house that you can
consider using a robot or an embedded network device for (maybe that’s just
how I think)! I need to dehumidify my crawl space. (Okay, maybe need is too
strong of a word.) Regardless, I am designing an Arduino project to sense
humidity and temperature, and automatically turn on and off a ventilation fan.
Sounds simple, right? Well, my abode is fully networked wired, so I thought that it
would be neat to be able to track humidity and temperature, as well as control the
fan. So, I decided to network the controller, as well. Long story short — I really can
just wire the fan to a switch and turn it on or off, but that isn't much fun. It’s funny
how the ability to do something sometimes confers upon us the need to do
Anyway, let’s answer a reader's question about mounting wheels to hubs.