I recently visited the Lake District for a short break. It's a place famed for its beautiful scenery, so I had to take my DSLR camera with me. I also wanted to be able to have pictures of myself against the scenery -- without having to go via the often-tedious route of the camera's countdown timer. This gave me the idea of using my Pebble as a remote shutter release for my Canon 60D. With no pre-packaged solutions readily available on the internet, I decided to embark on yet another DIY project.
There's an easy way to do this: buying a USB OTG adapter for your phone and plugging into your camera's USB port. However, not all phones have USB OTG support. If your phone does not have OTG support, I'll also be covering a second method that requires purchasing components and soldering them together. Both methods will use Tasker and Pebble Tasker.
USB OTG cable:
To use this method, you'll need an Android phone capable of hosting other USB devices. You'll then need a USB OTG adapter, and your camera's USB cable. Once you have the correct cables, you'll need to install Chainfire's Remote Release application. This will allow you to control your camera's shutter from your Android phone. In order to take advantage of this from your watch, we'll be making a Tasker task to trigger the shutter release. The Remote Release application doesn't include native Tasker support, so we'll simply simulate a screen touch to make things work. My phone is rooted, so I used shell commands (details here) to avoid having to install further plugins to Tasker. If your phone is unrooted, you'll likely have to find and install plugins to simulate a touch action (some people are reporting that the shell command method works on unrooted devices).
On my Nexus 5, the shell commands looked like this:
Once that's done, all you have to do is add the task to Pebble Tasker so that it can be activated from your watch.
DIY 3.5mm cable:
If your phone doesn't support USB OTG, or you want an alternative method that will keep your phone's MicroUSB port free, you can also build a cable that plugs into your phone's 3.5mm audio socket on one end and into your camera's remote port (2.5mm in my case) on the other end. This method uses an app called DSLR Remote.
The instructions for building the cable can be found here. I went with Variant A using optocouplers. The linked guide uses SFH 610A-4 optocouplers, but I ordered 10 PC817 optocouplers for £1.70 and they have the same pinout. I also ordered a 3.5mm male to 2.5mm male cable instead of buying a separate 3.5mm jack. If you do the same, make sure you scrape off the coloured insulation on the cable wires before soldering them to the optocoupler terminals. Here's what my (messy) cable looks like:
DSLR Remote also doesn't have native Tasker integration, so follow the same instructions as in the USB OTG method to create Tasker tasks for simulating the appropriate screen touches in DSLR Remote.
With the help of my Pebble, I was able to take cheesy photos like this: