Notes on using the photo booth mode in DSLR Remote Pro, PSRemote, Webcam Photobooth and NKRemote

Other articles on photobooth shooting: Overview

How to control lights when running a photo booth

This article describes how to turn lights on and off automatically when running a photo booth using either a Phidgets relay board (PhidgetInterfaceKit 0/0/4) or an I-PAC LED driver board. The LED driver board is suitable for powering LED lamps and illuminated switches without requiring an additional power supply (it is powered via the USB connection). The Phidgets relay board requires a separate power supply and is able to switch higher voltages and currents than the LED driver board. It is technically capable of switching mains voltages but please consult a qualified electrician if you intend to do this to ensure your booth is absolutely safe. If you need to control mains supplies it may be better to use a USB mains switch (e.g. products from or

Parts required:
1a) A Phidgets PhidgetInterfaceKit 1014 0/0/4 relay board available from
1b) An I-PAC LED driver board available from Ultimarc in the US or Gremlin Solutions in the UK
2) Power supply (not required for low power LEDs when using the I-PAC LED driver board)
3) Lights or illuminated arcade style buttons and wiring

LED bulbs used in arcade style switches like the one shown below can be connected directly to the LED driver board or to a 5V DC power supply when using the relay board. Standard LEDs need to be wired in series with a 1K Ohm resistor to limit the current otherwise the board, power supply or LED might be damaged.

LED bulb for arcade style button

Phidgets relay board

I-PAC LED driver board


Please download an install AutoHotKey if this is not already installed on your system. This is a free download from Then download and unzip the ZIP file containing the driver utility programs and the script to control the lights:

If you are using the Phidgets relay board you also need to download and install the Phidgets drivers from the Phidgets website. You don't need to install any additional drivers when using the I-PAC LED driver board.

When every thing is connected up you can test whether it is working by opening a Windows Command Prompt window and running PhidgetRelay.exe e.g. "PhidgetRelay.exe 1" to turn on relay one and "PhidgetRelaye.exe 0" to turn relay one off. You should hear a click as the relay switches on and off.
Or, if you are using the I-PAC LED driver, you can test it by running PacLED.exe e.g. "PacLED.exe 1" to turn LED one on and "PacLED.exe 0 " to turn LED one off. The I-PAC LED driver is completely silent and so you will only know it's working if you connect an LED to its outputs.


I-PAC LED driver board connected to a LED bulb mounted on a micro switch for an arcade style button

The photobooth_lights.ahk script

photobooth_lights.ahk is a simple AutoHotKey script is used to monitor the current screen being displayed by the photo booth software and to turn the relays or LED driver circuits on and off. It controls the lights by calling a small control program: PhidgetRelay.exe to control the Phidgets relay board or PacLED.exe to control the I-PAC LED driver board. Both programs take a single argument which is a decimal number where 1 turns on the first relay/channel, 2 turns on the second relay/channel, 4 turns on the third relay/channel, 8 turns on the fourth relay/channel etc. Multiple channels can be changed in a single call by adding the value together e.g. to turn on relays/channels 1 and 3 and turn off the rest you would use a value of 5.

If you are using the Phidgets relay board please edit the script using a text editor such as Windows Notepad and set the value of RelayExe to PhidgetRelay.exe:

RelayExe = PhidgetRelay.exe

Or if you are using the I-PAC LED driver board please edit the script using a text editor such as Windows Notepad and set the value of RelayExe to PacLED.exe:

RelayExe = PacLED.exe

In operation simply double click on the script in Windows Explorer and then run the photo booth normally.

The default bahavior of the script is to turn the first relay/channel on when the ready screen is displayed and off when it is not displayed. Please edit the script if you require different behavior. We can do this for you or write new drivers if you want to use a different device for the switching, but we will need to charge for our time to do this (please email for details).

Other articles on photobooth shooting: Overview