In our previous work we triggered the camera using an infra red remote control. In this new project we have converted to an electrical shutter release wire, fired by the arduino via an audio jack.
The main gain from this conversion is that we will then be able to use mirror lock-up to reduce vibration. This is not possible using the infra red remote control. We will also avoid losing occasional shutter releases when the sunshine in the room is so bright that the infra red signal get lost in the intensity of the sunshine. This has been an issue in summer before.
The design was adapted from Martyn Curry's system.
We did not alter the code on the arduino, as the commands that fired the shutter using the infra red remote control work that same way in triggering this system.
The parts and their prices are shown below:
- 4N25M optocoupler £2.20 (for 5)
- circuit board £1.94
- plastic box £1.96
- 470 ohm resistor (from bits box)
- cable £ 3.42 Total: £9.52
Here is the wiring diagram:
Here is the arrangement of the coloured wires inside the cable that goes to the camera. The colours are the colours of the wires inside the camera cable. The central column shows what the effect is on the camera of sending a signal down that wire. The third column shows which pin the wire is connected to on the 4N25M optocoupler.
Below are some photos of the work in progress:
These are the wires and the plate ready for soldering:
This is the system after soldering:
This is the old infra red trigger wires being reused to drive the new trigger: