1 to 29 minute alternative photographic process timer by Jim Read

Jim Read

The Alternative Photography Process Timer

1 to 29 Minutes in 1 minute increments

Warning
This is a DIY project that uses a low voltage to switch the mains voltage. This is not a project for anyone unfamilier with electronic components. The risk of serious injury or death (especially with the 240v mains in UK) could be high for anyone attempting this project without sufficient knowledge. If you would like to use the timer and have no understanding of electronics then find someone who does to make it for you.

In fairness though making the box and doing all the cutouts is far more time consuming than the actual electronic work, so it could easily be a joint project or even a supervised one.

The circuit.

Notes
S1 is the reset
S2 is the start.
S3 is marked 0 - 10 - 20
S4 is marked 0 to 9.
C2 can be a tantalum capacitor if you can obtain one.
The IC being the CMOS low current variety will run from a 9v battery, though you must be able to find a 9v relay.
This page will print onto an A4 sheet.

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