Hot Rod Red Robot Controller
I’ve always believed in working harder by working smarter. So when I do a task more than once, I take a minute to consider if I could make life easier for myself by making a tool, gadget, or program like this controller that will keep me moving forward instead of being stuck in the doldrums.
When I’m working with my PicAxe, Arduino, Raspberry Pi, or even just PLCs, I keep finding myself building the same kinds of prototype circuits over and over again. Circuits like switches, buttons, and potentiometers as voltage dividers or as current limiting devices come up all the time. I’m sure if you’re electronically-oriented, you have had the same happen with you. Instead of having these parts clutter up my solderless breadboard, I decided to make a controller that would house the devices that I could simply wire into my prototypes… and do it with style!
Since I’ve been building prototype circuits with these components for years and it’s mostly straight connections it didn’t take any effort at all to make the electrical plan. The real challenge of this project was planning out how the components I wanted would all fit on a single panel. On one extreme, I could make it a big, obnoxious contraption with everything I could possibly ever need, but completely unwieldy or on the other end of the spectrum, something so small and specific that it’s not useful. Aside from the use / aesthetic spectrum, I also have more than enough prototyping components, so one self-imposed limitation was that I didn’t want to go nuts buying all new stuff. That brought the challenge that I’d have to build the project around these two massive industrial joysticks that I have. If space is such a premium, then why two joysticks you ask? “To control robots”, I would answer. In the end, the limiting factor for the every dimension of the panel was the size of the joysticks. I managed to fit two switches, two potentiometer / rotary selector switch knobs, and five push buttons in the space between.
The build started off as a box with feet and a hinged lid which the components would be mounted to. That was going to give me the flexibility to easily open the cover and make changes, if needed. The hurdle with that design is that the lid, being made from very thin aluminum, would need to be reinforced so it didn’t flex every time you touched it. Also, there are the pointy corners to consider. Every iteration of a supported lid that I came up with was either clunky or complicated or both, so I decided that a fixed lid was the way to go and I’d just have to deal with reaching through the controller to make changes. Between the easy-to-manage handy panel siding and the square material used for bracing and the legs, it took very little time to build the enclosed bottom of the controller. The hardest part was visualizing interacting with the controls and planning where to put them and how to plan for the possibility of changes in the future. For this project and any others you might have dealing with sheet metal and drilling holes, I recommend you buy a set of step drills. Not only do they make much larger holes than you can practically make with general purpose drill bits, but they will also debur the hole after they cut it.
After I had the enclosed base fitted with the aluminum plate, I test-fitted all of the parts to make absolutely sure everything fits and painted the whole thing with red automotive paint. It’s not by best paint job, but it gets the job done. I may repaint the base or the plate with a different color to give it some personality.
Going forward, this will be great for prototyping. If I need a joystick in a permanent build, though, I think I’ll go for the mini joysticks available from Parallax or others instead of using a joystick almost as large as the robots I build.
That was my project day!