New Project: TB Timer – Timed Camera Cable Release

One of my other pastimes is Photography. I used to be ‘in the trade’, in fact, I have been a photographer and a photographer’s assistant several times. Nowadays, I pursue photography in a hobbyist sense. I still enjoy experimenting with exposures and recently, I was lucky enough to win a Lee Big Stopper Neutral Density Filter. I’d like to do some long exposures with this. The trouble is, I have no cable release to go with my camera. Sure, I could jump onto eBay or another website and order one of the myriad of pre-made cable releases but where’s the fun in that?

I have worked up a design that will hopefully fill all the criteria I need and be expandable too. I have settled on four modes:

  • B – Standard bulb mode where the camera shutter opens as long as you hold down the button
  • T – The shutter opens on the first press and closes on the second press
  • TB – Timed ‘B’ where the cable release is programmed with a time and the shutter opens for this amount of time
  • EX – Provision for an external trigger to connect sound and other sensors

It’s taken some research but I have built a prototype with my trusty ARDX Arduino Uno kit

TB Timer v1.00 Prototype

TB Timer v1.00 Prototype

Currently, the device changes mode with a press of the mode button which will later be incorporated in a suitable rotary encoder. I modified the prototype’s rotary encoder to remove the detents and therefore, have continuous motion rather than be stepped. When stepped, the value hops by two at a time. The ‘B’ and ‘T’ modes both operate as expected and at the moment, the rotary encoder changes a value in ‘TB’ mode and is displayed on the OLED display. the outputs are opto-isolated so will appear as switches to the camera. Although I’ll be using the cable release with a Canon DSLR, it should be very easy to make it work with other DSLR makes.

It’s early days yet and still to do are moving the rotary encoder code into the ‘TB’ function so that the time is only changed whilst in this mode. I’d also like to be able to change the value of minutes and seconds independently.

As with all ProjectAVR designs, the design files of the final boards will be available on this site as Open Source in due course.

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