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Standing outside all night watching the heavens is great in the
Summer, but when the bulb drops below zero it is not so much fun. I was considering building a remote device when I stumbled across
this website.
At the bottom of the page it said "if you need a timer circuit for a particular
application, email neil@reuk.co.uk with details of your exact requirements".
Incredibly, 5 days
later the small circuit you see in the picture below dropped through my letter
box. It took about an hour to dismantle my Canon RC-1 remote and hook it up to
Neil's electronics.
What the electronics does, by dint of a PICAXE programmable
microprocessor, is operate a relay (the blue thing) which simulates a human
pressing the button of the remote. It can be programmed by a simple push button
to give exposure lengths from 5 seconds to 10 minutes. Once started it will
give repeated exposures while the human operator keeps warm
indoors.
The timing
sequence allows for a small delay while the camera does a mirror lockup (to
lessen vibration), and if I choose to let the camera do dark frame subtractions
the timer will take that into account.
All that is now needed are some
adhesive Velcro tabs to attach the remote to some convenient spot on the
telescope.
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Testing the
remote timer
Programming
instructions |
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The modified Canon remote and
an ordinary one. |
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The timer.
The red LED confirms the time set, eg 10 seconds it flashes
twice; 60 seconds it flashes 12 times.
The green LED shows when the relay
closes.
The mode switch is for when I want
camera dark frame subtraction. |
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The remote attached with
Velcro.
The infra
red signal is aimed at the hand grip where the sensor is.
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After prolonged use the timer
started to give intermittent faults so a new device was built from scratch
using a Picaxe 18X chip.
An LCD display is used to provide a more user friendly
interface.
Set times
from 30s to 10 minutes can be chosen. The display
counts up in seconds and also shows how many frames have been
taken.
The right
hand button allows frames to be taken manually.
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