Team 116 OI Adapter board

This season, Team 116 designed and built Operator Interface Adapter boards to make OI prototyping and wiring of switches and potentiometers very quick and easy.

We’ll be at the NASA / VCU Regional, Richmond, VA and the Peachtree Regional, Duluth, GA.

Here’s the Team 116 Operator Interface Adapter Board page with images, and I plan to add additional info later. And here’s 2 adapter boards and a prototyping control panel in our team photo section.

It took a long time to hand-wire the boards, though it provided a good learning experience for soldering. Hopefully we’ll be able to get PC boards made for next season.

and here’s what it looks like (though the LED’s are no longer in the design):

This photo gives a good example of what these boards are used for.

As the web site says, this is a photo of 2 boards being used to connect a sample control panel to the OI.

Guiness Commercial Voice

And what type of connectors are those on the cables?

On the ribbon cables? and if so, which end are you asking about?

They’re called “insulation displacement” connectors. They squeeze right on to ribbon cable.

Where did you buy those game ports?

They look so professional and definitely much easier to wire to than soldering to each pin

Nice breakout box. If you made a PCB and sold em, lots of teams would buy.

They’re ordinary low-density 15-pin D-sub ribbon cable connectors. A number of companies make them. The ones we bought were Digikey part numbers CMP15T-ND & CFP15T-ND. They were the least expensive ones at Digikey, though they had some cheaper at Jameco, but we were in a crunch to order.

These connectors are pretty nice. They have built-in strain reliefs, and you can have the cable exit either out the side (like we did) or out the back. We used a vice to attach the connectors to the ribbon cables.

The connectors that attach to the PC board have separate strain reliefs available, which we ordered and added after these photos were taken (I forgot to order them the first time). That’s why the cables in the photos exit the PC-board connectors towards the center of the board (we built them with the plan to add the strain reliefs later). Now that the strain reliefs have finally been added, the cables properly exit away from the board. We also added pull-tabs with the strain reliefs, but I don’t think they are necessary.

Thanks. First we plan to have a few PC Boards made for our own team. And, while it has been mentioned, our team hasn’t yet started planning for any large-scale manufacturing of boards, but we will discuss it at some point, and hopefully we’ll have something available so other teams can benefit.

If we hear from lots of interested teams, it would certainly give our team a good push towards making something available.

We made something similar. It’s effectively an adapter that allows you to patch pots and switches into the OI. One connector goes to the OI, another goes to a joystick. A group of pins (with our traditional sig, +5, gnd arrangment) let’s you connect the pots and switches. A set of jumpers let’s you set whether each individual line goes to the joystick or its respective pot/switch pin. Sorry, but I don’t have any pictures.

You guys had a good idea with using ribbon cables though. Our boards just have right angle DB15 connectors, so we needed the 15 pin cables to go with them. That ended up being bulkier than expected.

We also made PCBs, homebrew style - cheap, decent quality, but not good for high volume. After you’ve got a design on the computer, you can print it onto a glossy magazine page with a laser printer. Then you iron it onto a copper clad board. The toner melts and sticks to the board. After it cools, you can dissolve the paper in water without hurting the toner. The toner is some kind of waterproof polymer, so it will work as an etch resist when the board is placed in your copper eating chemical of choice. Once the unwanted copper is gone, drill the holes and clean the board. Now, you’re ready to solder.

I’d love to see a photo of your board. I hope you can take some photos and post them.

One of my earlier design plans included a right-angle PC-board mount D-sub connector for the joystick, and a regular round cable and D-sub for the OI connection, but neither of those would have worked well with the pre-drilled boards we used. So that design restriction forced me to come up with the ribbon cable design, which I like a lot. My design ideas and plans went through many iterations before the board reached the form it is in now.

Among other things, I originally thought I was going to put some type of connector on each switch and pott, then I realized that was totally unnecessary, and would create unnecessary work later to prepare the switches and potts. Then I was going to use screw-terminal blocks, but that would require a screwdriver to use, and screws can loosen. Then I decided on the spring connector blocks, because they don’t require tools, and they don’t loosen.

Thanks for the tips on making PC boards. That could come in handy.

We thought about making our own PC boards, but it would require lots of jumper wires to achieve a single-sided design, and a double-sided design is a lot harder to do by hand. Also, there would have been 120 holes to drill in each board to mount all the parts (now down to 112 holes, with the removal of the LEDs, but still a lot of precision drilling).

Can’t you just use a CNC mill with an itty-bitty drill bit? :slight_smile:

I finally got some pictures. They’re a little hard to see, but I think you can get a general idea out of them.

Looks like a nice simple design. I did apply some sharpening to the photos to get a better look.

For future designs, you might want to consider the advantages of dip-switches over jumpers: there are no pins to bend or jumpers to lose. And, the advantage of spring terminals over pin-connectors: there are no pins to bend, you don’t need to attach connectors to the switches/potentiometers, and they can’t be bumped loose, though the pin connectors are more compact.

So, have any more teams designed nice wiring systems for their Operator Interfaces? We’re planning to have a few circuit boards made with my design. I’m planning to use smaller quick-wiring connectors, which will be easier on the fingers, and will make the boards smaller. Of course, I’ll update the info web page once the new boards are done.

I’ve always been so fascinated with the possibilities for the OI…

Last year (call me crazy), I tried designing a micro-controller that hooked to the dashboard port, which decoded the SERIAL and put it out to a CPLD, which then put it out to 7-Seg displays and a couple of LED-Matracies. This failed when I ran out of time, and my team told me that it was more important that the robot could move and stuff than have a cool OI (go figure?)…

Now you may be wondering: Why don’t you use a laptop with Dashboard?

I wanted to try to develop some hardware to be able to do this instead of relying on a super-over-qualified computer to do the job. If I was able to do it, I was planning on submitting the designs up here so that other people could try it (The whole thing cost under 100 dollars… Much more affordable then a laptop, let alone extra batteries…)

Anyway, getting back to the topic of this thread, this year I am thinking about running everything through ribbon cable. Essentially having boxes with lots of sockets in them accessible from the outside, and soldering ribbon cable to each pin, home-running it all to a box with a bunch of DIP switches on the outside to set which sockets are currently in use, with 4 DB-15 cables coming out of the box to the OI. This would allow for hookup of almost anything. They I could create adapters for parts that could allow them to simply be placed or removed from the sockets, in essence Hot Swappable

OK, I’m rambling, and if you actually read this whole post I am surprised, but I love this kind of stuff.


When you complete the development on either project, I’d love to see the photos and the write-ups.

My original idea was to use some sort of connector for each OI device (switch/pot/LED/etc.), like perhaps 1/8" audio plugs and jacks, so items could quickly be swapped, but it is essentially just as quick with the design we ended up building, and you don’t need connectors, and you only have to solder the wires at the device end.

We just finished etching this year’s version of our boards. The layout is essentially the same, but we tried photolithography this time. Much cleaner than the toner transfer method. They still need to be drilled, cut, and soldered though.

Very nice. Here’s a photo of our circuit board for 2007. I also updated the information page with the photo and a couple details.

That is actually pretty brilliant. While I was wiring the OI I was trying to keep it neat but it was still a mess in a way. I think that this way is much more organized and maybe I will try something more similar next year.