The image above is the interior of a specialized version of my Ultimate Remote. It does mouse and keyboard control for my laptop via USB plug-in. It also will do Bluetooth switch control on my iPad or iPhone. Like my other specialized remotes, there is an LCD screen and an Adafruit Feather M0 BLE. But what really makes this one special is that it includes a relay that can be connected by cable to a nurse call system at St. Vincent Hospital. The cable has a standard quarter-inch mono headphone plug on the other end that plugs into the wall in the hospital room. The white rectangular box on the right side of the image is a relay that can be triggered to call the nurse. By using a mechanical relay, it isolates my electronics completely from the hospital’s nurse call system. Although the hospital has allowed me to plug a cable with a simple pushbutton on the other end into their system, I don’t know if they will allow me to plug in this more advanced system. But I built it anyway just in case. The problem is, I can only handle one set of buttons at a time. Either use my Bluetooth and USB mouse and keyboard system or I can use the nurse call system. This box would allow me to do both at the same time.
The St. Vincent Hospital system is wired so that it is normally closed. When you push the call button, the circuit opens and it triggers an alarm to call the nurse. The system used to be normally open years ago. But someone realized that if you accidentally pull the cable out of the wall there’s no way to know that it is disconnected. With a normally closed system if the cable gets pulled out it would trigger the alarm. This system is not used for everyday patients. Most patients use a nurse call button that is wired into the bed. The jack in the wall is only used for specialized call buttons. But because their system is normally closed, you can’t just have an empty jack. Otherwise the alarm would constantly ring. They have a small “keeper” plug that sticks in the hole when the system is not in use.
Here’s the problem… I recently toured a skilled nursing facility on the south side of town in Greenwood. There’s a possibility that if my sister could no longer be my caregiver, I might have to go there to live at least on a temporary basis until I could find some sort of group home residential setting. I was thrilled to see that there nurse call system use the same quarter inch mono headphone jack to plug into the wall. It looked identical to the jack hole at St. Vincent with one exception.
There was no keeper plug stuck in the hole. That means that the Greenwood facility is wired “normally open”. When you push the button, it closes the circuit. My standalone cable with a simple pushbutton that I’ve been using at St. Vincent for years as well as my newfangled box are both wired as normally closed. So I built another cable with another simple switch and wired it normally open. Now I have one of each. One for St. Vincent and one for Greenwood Healthcare. But of course I didn’t want to build an entire new box for the advanced version to use in Greenwood should I need to go there.
Take a closer look at the terminals connected to the relay in my box. There are three screw terminals just below the relay into which we connected 2 brown wires that run to a jack on the left side of the box. Take a moment to appreciate what a wonderful job my dad did when wiring up this box. Those two brown wires have been perfectly trimmed to the proper length. One of them goes to the left terminal which if you look closely in this image is labeled “NC” standing for “normally closed” and the center terminal is the common terminal labeled “COM”. Unused on the right is a terminal labeled “NO” meaning “normally open”. All I have to do to convert the system is to move the wire from the “NC” terminal to the “NO” terminal. But as you can see… Dad’s perfect wiring job means that the wire is too short. We were both so proud of how clean the interior of this box turned out. Now I’m going to have to get someone to replace the wire with one that is about a half-inch longer.
We are pleased to announce that IRLib2 support for SAMD21 has been rewritten and greatly improved. It will allow us to and support for more boards using that processor much more easily.
Also the documentation available in Microsoft Word, Adobe PDF, and EPUB e-book format as received a major update. This is the first update or rewrite since the extensive 116 page manual was originally written.
The user’s manual now includes extensive details about support for SAMD21 processors such as those used in Arduino Zero, Arduino MKR series, Adafruit M0 boards including the Circuit Playground Express. We’ve also shared online a Google docs spreadsheet that gives a handy reference to pin numbers we support on the SAMD21 processor. You might find it a useful reference for other purposes as well. The document can be found at https://docs.google.com/spreadsheets/d/1rY79Hfl4f9e5TQBas_rWI3LeyTD8Hr-lhqi349ZwVXU/edit?usp=sharing
The documentation now also includes an explanation of protocol 12 CYKM which facilitates IR transmission of mouse and keyboard commands. These are especially useful in creating assistive technology devices for the disabled.
We are pleased to announce the release of the latest version IRLib 2 which now includes partial support for the Adafruit Trinket M0 and Adafruit Gemma M0 boards. IRLib2 is a library for Arduino and related boards that facilitates the receiving, decoding, and transmitting of infrared signals such as those used by TV remotes. The code is available on Github at https://github.com/cyborg5/IRLib2
All forms of input are available on any of the digital input pins. There are limitations however on the output pins. Neither of the boards support hardware PWM on the pin 1. So that support will not be forthcoming. Theoretically the Trinket M0 should be able to use pin 3 or pin 4 but for some reason we cannot get that code to work. Similarly the Gemma M0 should be able to do output on pin 2 but it does not work either. Both boards are configured to default output on pin 0 and that works fine. Alternately you can use pin 2 on the Trinket M0.
Late Update February 9, 2018: Resolved problems with Trinket M0. It can now use pins 3 and 4. Thanks to Limor “LadyAda” Fried who found the problem. I defy you to name another electronics CEO who will take the time to debug someone else’s library. Another in a long list of reasons Adafruit is such an amazing organization. It turns out there never was a problem with the Gemma M0. My initial tests must’ve been wrong.
IRLibCP has been updated for use with Circuit Python 2.x and has been tested on Circuit Playground Express using Circuit Python 2.2.0. Note that previously this library was only available for use on Express style boards because they were the only ones that supported the required “pulseio” module. Theoretically with Circuit Python 2.0 and beyond that module is available on non-express boards but we have not yet tested the library on those platforms.
There have been no changes to the code since the previous version. This update merely provides updated .mpy files compatible with Circuit Python 2.x.
We are pleased to announce a very early pulmonary beta release of IRLibCP. This is a Circuit Python module for receiving, decoding, and transmitting infrared signals. It is a translation from the original IRLib2 written in C++
Because the module depends on the “pulseio” module of Circuit Python it can only be used on “Express” versions of Adafruit boards. Specifically Circuit Python Express, Feather M0 Express, and Metro M0 Express. It cannot be used on other versions of Circuit Python such as Feather M0 Basic or BLE nor on ESP 8266 platforms.
As previously mentioned this is a very early beta release. Further example programs and updated documentation will be coming soon as well as refinements to the modules themselves.
In the ATMakers.org Facebook page we’ve been discussing the development of an assistive technology device we are preliminarily calling APHID. It’s my belief that at least one version of our APHID device will need some sort of display. Here is a proof of concept of the device using a feather 32u4, OLED display and three switches. It does every kind of mouse control that you could imagine as well as the limited keyboard commands. This device is connected through USB but we could also make a Bluetooth version.
In late 2015 I built a piece of assistive technology that I called my Ultimate Remote. The device was an infrared remote for controlling my TV and cable box. It also had infrared mouse control for my computers. There were also limited keyboard commands mostly arrow keys, enter key, backspace and some control keys for doing cut-and-paste. Finally it was a Bluetooth device for doing accessibility switch control on my iPhone. I wrote about it in this blog post from January 2016.
The core of it was an Adafruit Micro BLE device which was discontinued shortly after I purchased it. Adafruit replaced it with the Adafruit Feather 32u4 BLE. The Micro BLE also had an ATMega32u4 which is one of my favorite 8-bit processors.
The display was a monochrome 1.3 inch 128×64 OLED graphic display. It also contained one of my infrared I/O boards although it only did output. I didn’t really need to read any IR codes. On the end of a long wire were three lever micro switches that I would hold in my right hand to control the device.
The device served me well for well over a year. It was critical to me during my recent hospital stay where I was on a ventilator and could not talk. I used the switch control to type notepad messages on my iPhone and communicate with the nurses and doctors. You can read about that adventure here.
The micro switches have always been the weakest link in my devices. I have to use switches that have a feather touch to them and that means they are very fragile. The switches get knocked around quite a bit and so it was inevitable that one of them would break. About a week ago one of the switches failed and we had to replace them.
I had planned for many months to rebuild the entire device. I had used up all of the program memory in the device and could not add any new features or any new IR commands. I did not have codes installed for my Blu-ray player and there wasn’t any room left. In fact one time I had tried to recompile the code and because one of the included libraries had been updated, the code wouldn’t fit anymore. I don’t know if it was the Bluetooth BLE library or the graphics display library but something changed. I had to go through my code and try to free up some space by eliminating some error messages or shortening other messages. I finally got it to recompile but the writing was on the wall that I needed to upgrade.
The obvious choice was to use a new Adafruit Feather M0 BLE. Instead of the traditional 8-bit 32u4 running at 16 MHz with 32K flash memory and 2.5K RAM, I would have a 32-bit ARM Cortex M0+ running at 48 MHz, with 256K flash memory and 32K of RAM. The main problem was that my infrared library IRLib did not support these newer 32-bit ARM processors.
I had just recently spent weeks researching the new processor and converting my infrared library to support the newer chips. The timing and frequency modulation portions of my IR code are extremely dependent on the internal timers of the processor and that is very hardware dependent. I had to learn a whole new system of timers and PWM frequency control to rewrite the code. Fortunately I got it running just in time.
Although I had the infrared code working on the new processor, and had a Feather M0 BLE available to build a new device, it should not have been necessary to rush the new device into construction. All we had to do was repair the old remote by replacing the micro switches. I already had another set of switches assembled in anticipation of building the new remote. All we had to do was cut the cable on the old one, splice in the new cable and everything would be fine.
Dad decided that rather than having a stiff, unsightly splice in the middle of my cable, he would open up the box, unsolder the old cable and solder on the new cable. He ended up completely disassembling everything to get at the wires that needed replacing. I appreciated that he would go to that trouble even though this device was going to get replaced probably in a month or two. Unfortunately this was a bad decision.
Above are photos of the interior of my original ultimate remote. As you can see the wiring is pretty complicated. Unfortunately I only have about four different colors of wires available so we had to use the same color wires for different purposes. For example there are multiple green wires used for different purposes. After replacing the cable to the micro switches, dad tried to plug everything back in the way it was. We plugged in the device and I tried pushing the buttons but nothing would happen. In the course of trying to figure out what was wrong he touched one of the infrared LEDs and discovered that it was very nearly becoming more red than infra. It was too hot to touch. Although we did not get a visit from the infamous “Blue Smoke Monster”, if we had left it connected very long we would’ve had at least smoke and possibly fire as well.
It didn’t take us long to find out that the culprit was 2 green wires that had been crossed. We fixed the wiring and plugged it back in. No heat this time. The device worked intermittently for about five minutes and then quit working altogether. It was obvious that we had burned out the IR LED at least and possibly the transistors driving them.
Fortunately I had sufficient parts to build a new IR output board so we spent the next afternoon building it and installing it. It would not work either! One of the problems we were facing was that we had assembled and disassembled the box many times. I had been using small gauge stranded wire with silicone insulation. That is very flexible and made it easy to route the wires in a tiny box. However several of these wires were soldered into through hole locations on the circuit boards. Right at the point where they are soldered in, they are extremely susceptible to breaking if they are bent back and forth too many times. A better solution would have been to put a header pin in the hole. Then we could solder the stranded wire onto the pin and cover it with a piece of heat shrink tubing. At this point it was too late to do that.
We tried repeatedly to diagnose the problem with the new IR board but every time we fixed one thing, something else would break. There was also the possibility that we had damaged the Adafruit Micro BLE board itself. As I mentioned earlier, that board has been discontinued so there was no possibility of replacing it. After two full afternoons of working on it, I decided to throw in the towel and put all of our efforts into building the completely new device that had been planning for months.
I had all of the necessary parts. The new device would have a much larger 2.4 inch TFT color graphics display instead of the 1.3 inch monochrome OLED. This device also features a resistive touchscreen however I don’t have any use for that feature. It also includes a slot for an SD memory card. I may come up with a future use for that.
One of the nice things about the Feather Wing TFT board is that the feather board plugs into a socket in the backside. You don’t have to run wires from the main processor to the display board. However one of the disadvantages is that there is only one power and one ground pin on the device. So I was going to have to cut up a little piece of prototype board to make a power and a ground bus. This would bring in power from the outside, connected to the Feather and display boards, and run power to the infrared board. Similarly I needed ground wires to all of those parts plus a ground wire for the micro switches. We also needed to solder a jumper so that I can turn the backlight of the display off and on. There is a solder pad available but you have to jumper it to one of your Feather pins.
Although the Feather boards have a built-in battery connector and a battery charging circuit, I decided to power the device from an external 5v battery source. My old Ultimate Remote was a 5v device throughout while the Feather system runs on 3.3v. In the old system I had a short cable with a barrel jack running from the remote into a battery pack I call a Printy Boost. The Printy Boost is a device which I designed for the Adafruit Learning System as seen here. The Printy Boost also provides extended battery life to power my iPhone. So rather than have a separate battery for the remote and for the iPhone backup power I decided I would stick with the old system and run a cable from the Printy Boost into the remote just like I did before. Rather than connect to the +3.3v pin I connected to me “USB” pin which was the same as powering it through the USB cable at 5v.
There are some differences between the Feather TFT board and the old monochrome OLED graphics board so I had to tinker with the software to get things to run. Most of it was compatible because Most of the Boards operate on the Adafruit Graphics library but there are still differences. Once I had display software converted I tried using the device. Unfortunately it didn’t work again! You would think I would be more careful about crossed wires after the previous fiasco. It turns out we had the infrared I/O board wired backwards. I had drawn the wiring diagram looking at the front side of the IR board. That means on the right 2 pins are power and ground. Then moving to the left you skip one pin and the next one is the IR output. However the way the board is oriented in the device, the backside of the board is facing upwards. We wired it with power and ground on the right but that was wrong. Fortunately this just meant that the power lines were going to the receiver pins which were not being used in this application. So nothing burned out. We reversed the wiring and everything worked fine.
The final step was to design a 3D printed enclosure for the device. That took another afternoon or so.
We mounted the TFT display into the lid of the box using black nylon plastic screws and nuts out of this kit sold by Adafruit. They are really handy because they are selected to fit in the 0.1 inches diameter mounting holes used in most Adafruit boards. When that box of screws was first added to the Adafruit catalog I knew I would need them someday and purchased it right away. They work perfectly so it was a great purchase.
The rest of the box is held together by 5/8 inch sheet metal screws. I like using sheet metal screws because they have a pointy end that taps really well into 3D printed PLA plastic. Here are some more photos of the completed project.
There are still lots of software tweaks I have to implement. It takes longer to erase a 320×240 color display than it does to erase a 128×64 monochrome display. The monochrome device required you to call a “display” method to update the display after writing to it. The new color device updates as you write to it. The result is you can see the screen update where the old one would update instantly. I think the updates actually slow down the entire process a little bit. So I’m going to have to optimize the code so that it only updates the screen when absolutely necessary and only does it in small pieces. In the old system it was easy to just erase everything and redraw it from scratch every time but that won’t work very well in the new system.
Of course I also have to add all the features I’ve been wanting to add but didn’t have sufficient memory under the old system. I have to add all the codes for my Blu-ray player and there are some additional keyboard codes that I want to add. I may end up implementing an entire keyboard system so that I can type anything using IR codes. I’ve developed a special protocol for my IR library that allows me to use any mouse or keyboard commands possible. I’ve only been using a fraction of that capability.
One other difference between the old and new system involves the power output of the IR board. When I originally designed my infrared I/O board I ran the LEDs with no current limiting resistors. Because the LEDs are only intermittently running (assuming you don’t cross your wires), it’s safe to put more than 1 amp through them. But my experience is that sometimes USB power can’t supply enough power when that current spikes during transmission. So I’ve added some 33 ohms current limiting resistors in line with the LEDs on the latest version of my infrared I/O board. The old device did not have these resistors but it ran well because it was powered by a battery pack rather than a USB plug. Now that I’ve worked with the new remote I’m realizing it doesn’t have the power of the old one. I’m going to try shorting across those resistors and see if it helps.
I still have fond memories of my original Ultimate Remote. It served me well for over a year and was literarily a lifesaver while I was in the hospital. But I’m also looking forward to the new things I will be able to do with the new improved Ultimate Remote 2.0.
Afterward: After I completed the project I presented it on the weekly Adafruit Show-and-Tell. I was the first guest in the video below.
A few weeks ago we released IRLib 2.01 with preliminary support for SAMD 21 processors such as used in Arduino Zero and Adafruit Feather M0 boards. Then initial release had many hardcoded values. For example output was only available on pin 9 and the timer interrupt for the 50 µs receiver class was hardcoded to use TC3.
In our latest release IRLib 2.02 you now can use any available PWM pin on your platform for output by editing values in IRLibProtocols/IRLibSAMD21.h
You can now also choose to use TC4 or TC5 to drive the hardware interrupt for the 50 µs receiver class.
Both sending and receiving use GCLK0. Note that typically GCLK0-GCLK3 are reserved for internal Arduino infrastructure use however we are using GCLK0 with its default clock source of 48 MHz and a divisor of 1. Because we are not modifying those defaults, it is safe to use. That allows you complete freedom to use GCLK4-GCLK7 for other purposes.
The code has been tested on Arduino Zero, Arduino M0 Pro, and Adafruit Feather M0 BLE boards successfully.