Take control of your DSLR with the Triggertrap Mobile Dongle and app

Back in 2011, Haje Jan Kamps came up with a fascinating idea for a Kickstarter -- the Triggertrap. The idea was to create an interface that would go between a digital SLR camera (DSLR) and a smartphone, with an app on the smartphone to control activation of the shutter on your DSLR. The Kickstarter project was a success, and the Triggertrap is a reality. I had an opportunity to test a Triggertrap and the app with my Canon EOS Rebel T4i DSLR and found it to be a well-designed and implemented product.


The Triggertrap uses a combination of a dongle that attaches to the headphone port of your iPhone and an adapter cable that plugs into the dongle on one end and the camera on the other. The two-part design is quite smart; not only does it provide electrical isolation between your smartphone and camera, but the dongle is always the same -- it's just the adapter cable that changes depending on your DSLR.

Triggertrap works with most DSLRs (there are over 300 supported camera models), and the company provides a comprehensive list of which cable works with a particular camera. In the case of my camera, I was advised to get the MD-E3, which included both the mobile dongle and adapter cable. The price of the kit was only US$31.24. Additional adapter cables are available for my camera are only $10.57, and a second mobile dongle is just $26.43.

How does Triggertrap work to control your camera? It does it sending high-frequency sound pulses from the audio port of your iPhone or iPad to a corresponding remote control port on your camera. In most cases, the camera's autofocus must be turned off, and for some of the Triggertrap modes you'll want to put the camera into Bulb mode.

The final piece of the puzzle is the Triggertrap app. It's free, and it provides a number of different ways of triggering your DSLR's shutter:

  • Simple Cable Release: acts like a mechanical cable release would -- tap a button on the app screen, and it takes a photo.

  • Press and Hold: this is a long-exposure mode. The button is tapped and held, and the shutter stays open as long as your finger is on the button. Take it off, and the shutter closes.

  • Press and Lock: another long-exposure mode. Tap the button to start the exposure, tap it again to stop the exposure.

  • Timelapse: select an interval between shots and tap the button to begin shooting, tap it again to stop shooting.

  • TimeWarp: It's a timelapse photograph, but the interval between shots gets shorter towards the end, giving the timelapse series the illusion of speeding up.

  • DistanceLapse: camera is triggered to take an image every time it moves a certain distance (useful if taking time-lapse images of a driving trip).

  • Star Trail: takes a number of exposures of a particular duration with a time gap between them.

  • Bramping: "bulb-ramping", taking a large number of exposures over a long period of time, starting the exposures at one duration and ending at another duration.

But wait, there's more! There are two sensors modes:

  • Sound sensor: uses a sound to trigger the camera; for example, a clap or whistle will trigger.

  • Vibration sensor: triggers the camera with a vibration or earthquake (!)

and two long-exposure HDR modes:

  • LE HDR: takes multiple long exposures with an EV (exposure value) change each time.

  • LE HDR Timelapse: timelapse of multiple LE HDR images.

And there's more!

  • Wi-Fi Slave mode: Use another device on a Wi-Fi network to trigger the DSLR connected directly to the Triggertrap.

If all of those different modes confuse you, there is a troubleshooting guide, a "setting up Wi-Fi" guide, and even an introduction to the Triggertrap team in the app. The app is done in bright red and white colors in an iOS 7-friendly style, and also includes a button for buying a dongle and adapter cable from your iPhone!


I didn't have the time (or patience) to test all of the different Triggertrap modes, but I did connect it up to my Canon DSLR to try most of the simple modes. Initially I was having some issues, but then I followed the directions and turned the volume on the iPhone all the way up. That did the trick, and the Triggertrap followed my instructions perfectly the rest of the time.

I'm absolutely amazed that the Triggertrap team has created such a compatible and powerful tool for photographers that costs so little and does so much. The world of photography often seems to be filled with overpriced single-tasker devices that work with only one model of camera, while the Triggertrap leverages the power of the iPhone to provide a tool that can handle just about any DSLR on the market.

There's a pretty amazing Flickr group that highlights the work that has been done using the features of the Triggertrap, so I suggest taking a look at some of the photos to see just what you can do with this device.


Between the low-cost open source hardware (there's an Arduino version available as well) and the power of the free app, Triggertrap has created an affordable photography tool that should be in the equipment bag of every professional and dedicated amateur photographer.


  • Insanely affordable

  • Compatible with most contemporary DSLRs

  • A wide variation of exposure triggering methods are available through the app

  • App is stable, well-written, and iOS 7-friendly

  • Ability to trigger the Triggertrap remotely via Wi-Fi makes up for the relatively short cable


  • None to speak of

Who is it for?

  • Any DSLR and smartphone owner who wants the ability to experiment with a wide range of bulb exposure and timelapse modes