The Public Lab Store Starter kits for DIY environmental science

Shutter Timer

This timing circuit outputs 5 volt pulses to the USB ports of Canon PowerShot cameras to synchronize the release of their shutters. When the remote function of CHDK is running on both cameras, the start of a pulse to the USB ports activates a "half press" of the shutter button and all automatic focusing, exposure, etc is done. When the pulse ends, the shutters of both cameras operate simultaneously to take perfectly synchronized photos. The timer allows adjusting both the interval between pulses (2.5 to 60 seconds) and the duration of the pulses (0.5 and 5 seconds). An indicator LED is lit during the pulse.

This timer allows two-camera infrared systems to take synchronous pairs of normal and near-infrared photos for combining into false color IR or NDVI images. This is the timer included in all Titan 2 IR packages here. Synchrony is critical when the cameras are moving if the photo pair must be aligned to make a composite image.

Includes timer, 3D printed enclosure, battery box with on/off switch (for four alkaline AAA, not included), two Mini-B USB cables, two Velcro ties, Velcro tape, and the MK111 assembly and specification sheet. Completely assembled and tested. Total weight with batteries is 125 grams.

The timer is an MK111 timer (based on the 555 IC) which has been modified to operate on low power. Instead of operating an electromagnetic relay which switches a separate power source to the devices (the cameras), the relay was eliminated and the same batteries that power the timer also power the cameras. Any six volt source can power the device, so the very small 4LR44 battery will work. Alkaline AAA batteries are easier to find and four of them will power the timer for many hours.

More information is available in the guide for the build-your-own Shutter Timer Kit at the Guides page.

How to use the timer with two Canon PowerShots

  1. The pulse length and pulse interval can be adjusted with a small screwdriver by turning the slotted screws on the two potentiometers inside the 3D printed box (labeled pulse and pause). They are currently set to take photos about every eight seconds with a two second long pulse. So the cameras get ready to fire at the start of the pulse and then fire 2 seconds later when the pulse ends, and then wait a few seconds to start over.
  2. The two Canon PowerShots must be running CHDK with the remote ("one push," "normal") and remote synch options activated (CHDK Settings/Remote Parameters).
  3. With the cameras powered on and running CHDK, the USB cables plugged into the cameras, and the timer turned on, the cameras should shoot simultaneously every eight seconds.
  4. A window in the printed box reveals the red LED which is lit during the pulse.
  5. The four AAA batteries must be 1.5 volts each, so alkaline batteries are best. Some rechargeables are only 1.3 volts and don’t work. The timer needs fresh batteries; old worn out ones will not work, but a fresh set will last for many hours of operation. If one or both cameras fail to shoot regularly, check the timer batteries.
  6. An assembly and instruction card for the timer is included.
  7. Velcro straps are supplied for the battery case and timer case. Wrapping a strap around the case and the frame of the aerial camera rig is important to secure the case during flight. Velcro tape on the frame and the bottom of the cases make them more secure.

 

Wholesale

Want to carry our kits in your own store? Order wholesale! Contact the kits team.

Community Science Forum: Frac Sand

Our quarterly print publication has a new name, and a wider scope. It's now called the Community Science Forum. This issue is focused on frac sand, and in particular on the work being done in western Wisconsin by community groups concerned about air and water quality impacts of mining operations there.

Usually $5, we're offering the new issue at an experimental price of $2 plus shipping.

Event Packs

Do you have an event planned and would like to introduce Public Lab to your community? Order a $10 Event Pack with GMF and foldout maps!

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