Archive | January, 2012

Bluetooth Camera Remote

15 Jan

Recently I have been experimenting with interfacing my Ardunio Uno with my Nikon D200 DSLR. The D200 has a connector for a remote control cable that consists of 10 pins. After some research on the web I was able to find some information on how the pin layout works: http://www.doc-diy.net/photo/remote_pinout/#nikon. Basically, you have to connect the two pins  for activating the autofocus and the shutter to the ground pin in order to take a picture.

The pin layout of the remote connector

As I do not own a remote for this camera or a cable that fits into the remote connector, I used breadboard cables which fit perfectly into the pins of the connector. With these cables and an optoisolator, it was easy to connect the camera to my Arduino board.

The remote connector of the D200

Some experiments showed that activating the optoisolator for 1000 milliseconds was a good value to activate the camera for one shot (this can also be done by simply bypassing the three cables. This opens up many possibilities for triggering the camera for example with a lightbarrier (for example using an IR diode and a photodiode), or by sound sensors or other means of activation (such as a photo resistor for detecting ambient light and automatically shooting sunsets if you are too lazy to get up early).

The Arduino board (with Bluetooth Shield), connected to the optoisolator

However, as I was recently experimenting with the Amariono toolkit (http://amarino-toolkit.net/) that enables the interfacing of Arduino boards with Android devices over Bluetooth, I decided to build a remote control App that would be able to trigger my camera wirelessly: a Bluetooth Camera Remote.

The Bluetooth Camera Remote Prototype

The BTCamRemote consists of several components:

  • An Arduino Uno board with an optoisolator connected to the right remote trigger pins at the DSLR.
  • A Bluetooth Shield (I use the one from iteadstudio.com).
  • An Arduino program that depends on the Amarino Library and listens to commands that are recieved over the Amarino framework (basically consisting of a certain flag and an Integer value that sets the duration for activating the optoisolator and thus the camera).
  • An Android cellphone (I use an HTC Legend with Android 2.2) running the Amarino App (where the connection to the Arduino has to be set-up, coupling the Bluetooth devices).
  • An Android App that uses the Amarino Framework to send commands to the Ardunio board when a button is pushed (the user can also set a delay before the command is sent, so you can hide the cellphone when you want to take self portraits).

This setup is not really simple (because of the many software components), but it works and can be easily extended with further functions (for example activating other pins with further optoisolators etc.). It is also possible to use the Arduino for long term exposures, for instance when taking night shots (as far as I know, the camera can do exposures up to 30 seconds without using the manual “bulb” mode; the Arduino could control exposure times that are much longer, and it could be easily made accessible with a nice user interface on the Android phone.

The Android App “BTCamRemote”

The next steps will be to solder the circuit to a (smaller) circuit board and exchange the breadboard cables with the right camera cable. I will also try to attach the Arduino board to the hot shoe of the camera, and power the Ardunio with a battery in order to make the setup more mobile and easier to carry around. It would also be nice to learn more about how the other pins on the connector work, in order to access more camera functions with my remote.

You can download the source code as well as a signed APK of the application here (note that it depends on the Amarino App that has to be installed separately): https://bitbucket.org/boden/btcamremote/