Category Archives: Adaptive Technology

Solid State Relay (8) With Capacitive Input

For my Maker Toolbox, v1 of my Solid State Relay (SSR) breakout/test box. Relays are triggered by Capacitive input via a CAP1188, controlled by Pro Micro (or Nano, or QT PY, or similar).

As a PoC, I tied the CAP to the SSR for triggering (in the code, I reverse the polarity of the LEDs — like Doctor Who would do). I’m not happy with this method, as all relays trigger for a moment during startup. Since I’ve got the MCU in there, I may modify to Arduino direct to SSR, with software control.

Magnets For Enclosures

I’ve some projects where I want an enclosure, but need to get at the innards frequently. I gave up on screws, and don’t know enough SCAD to do interlocking tabs, so I went with magnets. The capacitive relay setup is a good example. Four 6x2mm magnets — two glued to the bottom, two to the top. Holds the top on great (even upside down), yet easy to pop off. And, if you’re really nutty like me, flip the mirrored magnets around so that the top only snaps together one way. 🙂 I use E6000 or similar for glue.

Optic Isolation For XBOX Adaptive Controller

Here’s something I’ve done for my XAC prototype inputs. If I’m not using a simple switch (aka a “dumb” on/off), I want to optically isolate the sensor (ex. capacitive touch, hall, etc) from the XAC. Mostly because I don’t want to burn out my XAC. 🙂

Anyhow, here’s where my ham radio roots show: I “dead bug” solder a PC817 photocoupler to a 3.5mm jack. A resistor (around 470 is fine) is also needed on the source side (remember–there is a little LED in there, and you need to drop current as appropriate).

The soldering is a little fiddly, but it comes together in a clean package. I keep a couple of these on-hand so that I can more quickly prototype. (Same reason I did those solid state relay boxes.)

Testing them is easy — connect it to Ground and D13 on an Arduino, and run the “Blink” sketch. When plugged into an XAC port, and the program running, you’ll see the button go on and off.

Ring Switches

While pondering a “ring switch” I was reminded of another low-tech solution. Two screws placed close together. Metal ring across them will complete the circuit. (Disclaimer: Low Voltage Only! Keep it under 24VDC.)

Since I’m known for over-engineering, I made a quick 3D printed version to test it out. No soldering — screws hold pre-stripped wires in place. Threw in a magnet to attach it to anything ferrous/magnet friendly, or use double-faced foam. Since the end of the cord might droop, I modeled in a plug holder to take some strain.

Not the target solution, but a good early morning thought problem. 🙂

Documenting IR REmotes

The adventures of Taylor D. and the automatic door with missing IR remote got me pondering. We need an easier way to document IR commands. I know, learning remotes, pretty well documented TV codes, and the well trodden path of the Arduino IR Remote library. But I’m thinking those weird IR remotes that come with assorted electronics.

While we can always wire up an Arduino, IR detector, and read some serial values, I want something that I can toss into a toolbox. I’ve done some searching, but most seems ad hoc or learning remotes (not documenting).

In the field, the Maker can use the gizmo to record IR codes from a no-name remote (many of them use some variation of the NEC protocol). Then those numbers can be written down and posted publicly. So when the remote gets lost, it can be recreated.

This won’t help the already lost remote situation, but if we can record this stuff during install, and — heck — print out and file the codes, I think it would save future heartache. And means we don’t have to throw out a perfectly good piece of equipment just because the remote is gone.

I’ve made some initial progress, and am busy hunting down all my “custom” remotes to see if I can read them. If I’m successful, I’ll post the code & models & required parts.

On the roadmap, I’ve got RF, too. But that’s a trickier one. Probably will give me a chance to finally use my ADALM-PLUTO SDR.

For the Proof of Concept, I’m using some boards I had on hand. They have an ESP8266, charger, ON/OFF SWITCH!, screen, joystick. Great, right? Except they made some horrible I/O design decisions — in other words, don’t use this for new work. A real shame, since it’s a wonderful collection of items on one board.