Media Control and Video Log #3

A project log for Custom Smartwatch

An ESP32 Based Open-Source Smartwatch

Matthew James BellafaireMatthew James Bellafaire 08/03/2020 at 00:490 Comments

                Recently I had some time and put some more work into this project on the BLE side of things. Overall BLE communication with this project isn’t where I would like it to be and there are still a few bugs and issues with reliability, however I’m finding better ways to use BLE as this project progresses. Since the last log I’ve added some functionality to the android app allowing for specific commands to be written by the smartwatch to trigger actions on the android device.

                The smartwatch itself will now attempt to connect to the android companion app whenever it comes out of sleep mode by the user tapping the screen. The connection status is indicated by a small square in the upper right-hand side of the screen (red = not connected, green = connected). With this constant connection there are a lot more options available to future functionality of the watch since the most time-consuming part of BLE was the scanning and connecting phase. When connected the communication speed between the watch and android device is fast and more than capable of streaming even long sections of text quickly.

                With these improvements it’s much easier to communicate between the two devices so I decided to add my favorite feature from my old android ware smartwatches, media control. For the most part I only listen to music on Spotify these days, and unfortunately Spotify seems to enjoy doing things their own way. In order to read the current song being played by Spotify the android app uses a broadcast receiver following the documentation provided by Spotify ( Although I’d much rather read the currently playing song from the notification bar it seems Spotify doesn’t really allow for this, meaning implementation with other players will have to be implemented separately. The media controls triggered from the smartwatch are simple key-events which the companion app creates when it receives a command over BLE. I haven’t yet investigated reading media information from other android media players, so I’m not sure whether Spotify works very differently from other apps. 

                The media control interface itself was meant to be simple and easy to use while locating itself directly on the home screen. The media buttons will appear only when the android app detects that Spotify is currently playing. If the smartwatch is connected to the android device then the media controls will work immediately, otherwise the action will be queued until a connection is established. In general, the smartwatch can connect to the android device immediately when the android device's screen is on, otherwise it can take a few seconds or fail outright. 

There have been a lot of improvements to BLE recently in this project, however there is still a lot of work to be done in this area. I've noticed that the ESP32 connects unreliably when the android device is in doze mode. By taking a look using some android BLE apps available on the play store I've been able to determine that the android device is advertising properly. Most likely the issue is on the ESP32 side of things, as a result I’m planning on redoing a lot of the BLE code to try and improve the overall reliability of the project. 

I also realized recently that the last video update for the project is now nearly a month old, and a lot of work has happened in that time. I've decided to try and do regular video updates for the project, since so much of what is happening in this project at this point has to do with the user interaction it’s much easier to show rather than write about. The video logs are meant to be parallel to these project logs and represent a short overview of improvements to the project. Anyway, here's the third project video log: 

Either way thanks for reading and I'll see you in the next log!