My middle child recently had an evaluation regarding her processing and retention in reading. She has diagnosed ADD, and aside from the specific results of her tests, the specialist recommended we look for and purchase a device that would buzz her wrist at regular intervals when doing homework and reading. The goal is to refocus when one is easily distractable. It’s a bit like Apple’s “stand up and move” reminder.

However, when we headed over to Amazon, we were met by two realities. First, these things cost a lot. Second, they have terrible reviews. It occurred to me that I could probably put together a band with things we already had around the house.

Last summer, I did a little work exploring BLE, the low energy form of Bluetooth that works with iOS. My test platform was the 1st generation Mi Band step tracker, which I purchased for under $20. The second generation is similar and appears to cost under $30. (Here’s a link to the first gen model, which is sold by third parties.)

My build consisted of the following components:

• I built a basic single-view app and added a single centered segmented control. The control specifies the time-out interval, which is simply a standard Timer.
• When the Timer activates, it uses my Bluetooth helper type to write a single byte to the band, which causes it to buzz. It’s slightly more complicated than that because the code needs to scan for the device, discover it, stop scanning, and then write to the peripheral, but that’s all covered in my previous posts.
• To keep the app running longer than 3 or 10 minutes in the background, I resort to the standard “play a silent wav file over and over”. I based my code on this simple github repo, which handles audio interrupts and restarts.
• I added every background mode I thought potentially applicable: plays audio/video streams, uses CoreBluetooth, provides VoIP services. I could probably have dropped the first one but it does no harm so I kept it.

Testing was, as you’d expect, a bit tedious, especially trying to figure out whether I had beaten the automatic time out (which is why went from my custom code to the github version for keeping alive). I put the pedometer portion on an empty diet coke can, to make it buzz a lot louder without having to wear the band.

In the end for a few hours of my time and under $20 capital investment, I ended up with a handy little tool. My daughter has only been using it a few days so it’s still too early to see whether the refocusing component is actually effective.

If you want to give this a try, I’ve put up gists for the primary view controller and the bluetooth controller. You can grab the background handler from the above github  repo link. I didn’t bother cleaning up any of my code, so it is what it is, which is a working prototype. Don’t forget to add the background modes to your Info.plist.

If you build this yourself (or just intend to try it out), drop me a note or a comment and let me know how it goes.