Unattended Photography of Birds
By Tony Turner
When the Canon G2 was released in 2001, its resolution of 4 Megapixels made it ideal for photographing birds in the wild. The 32 Mb Compact Flash (CF) card could store 30 or 40 high resolution images.
Breeze Systems quickly released a program called “G2Remote” (and a later version "PSRemote" which could control the G2 from a laptop computer via a USB connection to take images. The settings chosen were to take an one image every ten seconds and store them directly onto the laptop's hard disk. This could continue until the laptop's battery ran out or the G2's battery ran out. It was possible to store 500 or 600 images in a session.
In the last year or two, dramatic increases in the capacity
of CF cards, first to 1Gb and then to 2 Gb meant that a full session's images
could be stored in the G2, and if a method could be found to trigger the
camera, the laptop would become unnecessary.
The Canon G2 (and subsequently the G3 and G5) has an
infra-red wireless remote hand-held trigger which sends a series of pulses,
unique to Canon, which are received by a sensor in the front of the camera and
activate the shutter.
We dismantled some of these triggers, cut some of the tracks on the printed circuit and soldered them to timed relays so that they were activated every ten seconds. Pointed directly at the receivers on the cameras, they were effective at up to two metres from the cameras.
The relays required 12Volts and the triggers required 3Volts, so each device required ten batteries.Automatically takes photos every 10 seconds saving images to the Compact Flash Card (CF).
Note the G2 camera has a limit of 2 Gb cards.
After months of experimenting and asking questions on the internet, we discovered the exact values and timing of Canon's pulses. We could now write a program for a Programmable Integrated Circuit (PIC) to generate and time the pulses, superimpose them on a carrier and activate the Infra-red diode directly every ten seconds, and do away with the timer, relay, trigger, and all those batteries. The PIC chosen was the Picaxe M08. The whole device fits into a switched battery box which is designed to hold four AA cells. Three of the compartments hold AA cells and the fourth holds the electronics. The assembly is small and light enough to fit into the camera's hot shoe with the infra-red diode pointing downwards towards the camera sensor from a distance of a few centimetres.
PICAXE-08M microcontroller chip. Supports 5 input/outputs including 3 analogue inputs.
The PicAxe has only 255 bytes for code.
PicAxe programmed to takes photos every 10 seconds.
With the Canon G2 battery life and filling a 2 GB CF card, this provides 2 hour photo session .
The G2 can accept pulses more frequently than every ten seconds, but is not always predictable. It seems to store images on the CF card fairly regularly then pause a bit then resume taking images. We reprogrammed the PIC to send out pulses every half-second instead of every ten seconds so that the G2 would accept a pulse as soon as it had disposed of each image, and was thus able to average an image every five seconds.
The overwhelming numbers of images available daily was becoming impossible (more than 900 images per camera per session), so it was necessary to find a method of taking images only when a bird was present. There is a nightlight available on eBay from China that has a Passive Infra-red Receiver (PIR) that senses a moving human body and turns on six white LEDs to illuminate doorways or stairs or so on. Suitably shrouded, (in this case using a stubby drink holder with a slot cut in the base) this device can be triggered by a moving bird. One of the six LEDs is removed and the voltage that had been applied to it is instead diverted to an input pin on the Picaxe. A radical bit of reprogramming has the PIC idling until it senses a signal from the PIR, when it sends pulses to the camera for one minute, then idles again until the next bird movement.
Using a Passive Infrared (PIR) motion detector - the PicAxe
isprogrammed to take one minute of photos (approx 12) each time motion
The PIR suitably shrouded, (using a black stubby drink holder with a slot cut in the base).
One of the six LEDs is removed
The Passive Infrared (PIR) motion detectors have been setup for different purposes
1 PIR to trigger two camera
The Canon G2 with PiThumb and PIR (enclosed in black drink holder) clamped to the tripod with its rain hat (kitchen plastic container)
The modified PIR is clamped to the tripod with a cable to the PiThumb.
Kitchen plastic containers were painted for camouflague and to protect the cameras from rain.
The PiThumb Setup for sideview of Big Mound
Canon G2 camera with PiThumb under its rain hat.
Small tripod strapped using computer cable ties to wooden tomato stakes.
The PIR close to the mound.
The mounds had twigs placed on the top to be a quick check if the male had come to the mound during the photo session.
PicAxe programmed to take photos for 30 seconds at setup then for each motion detected, photos every 3 -4 seconds for 10 minutes. This has allowed for photos sessions of > 7 hours.
If no PIR is connected then PicAxe to send out pulses every half-second thereby contiunous shooting (< 2 hours limit per session)
The Canon and Pentax DSLRs have no comparable hand-held remote. A solution here was a wireless PIR doorbell, also from eBay. The doorbell unit has a PIR that can be triggered by a bird, and this wirelessly activates the chime unit which can be twenty metres away. The chime speaker is disconnected and its voltage signal diverted to a Picaxe which is programmed to close a solid-state relay twelve times in one minute. This relay activates the DSLR shutter via its wired, plug-in remote.
The unit on the left is the PIR which senses movement using the translucent window near the top. It sends a signal wirelessly to the receiver on the right and normally plays a tune through its speaker.
Sourced from eBay
Email lyrebirdman at gmail.com