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A battery powered timer with a settable OFF time and ON time. Dual output relay connections accessible via screw terminals.

Over the years I have build many timers and of course many Apps abound for your mobile phone. But when I really wanted one to simply automatically switch on and off a circuit that I was working on, none of them fitted the bill. So I built this relay timer.

In Menu mode (timer not running), the Stop & Start buttons step through the following configurable items:

- Off format - Displayed as “OF F” - Determines whether the OFF time shown is in hours and minutes or in minutes and seconds. Use the Up/Down buttons to switch between two options. Either “HHnn” or “nnSS”.
- Off time (left two digits flashing) - Displayed as “OF t” - Represents the OFF time hours or minutes depending on the OFF format selected. Use the Up/Down buttons to set the left two digits.
- Off time (right two digits flashing) - Displayed as “OF t” - Represents the OFF time minutes or seconds depending on the OFF format selected. Use the Up/Down buttons to set the right two digits.
- On format - Displayed as “ON F” - Determines whether the ON time shown is in hours and minutes or in minutes and seconds. Use the Up/Down buttons to switch between two options. Either “HHnn” or “nnSS”.
- On time (left two digits flashing) - Displayed as “ON t” - Represents the ON time hours or minutes depending on the ON format selected. Use the Up/Down buttons to set the left two digits.
- On time (right two digits flashing) - Displayed as “ON t” - Represents the ON time minutes or seconds depending on the ON format selected. Use the Up/Down buttons to set the right two digits.
- Loop - Displayed as “LOOP” - Determines when started whether the sequence is played once or is repeated continuously. Use the Up/Down buttons to switch between two options. Either “ON” or “OFF”.

When in Menu mode and the menu shows “PLAY”, pressing the Play button will start the timer. If you haven’t set a OFF time or ON time, the bottom line will show “Err” and returns to Menu mode. Should either the OFF time or ON time or both be set, the timer will start. The buttons have the following functions:

- Stop button - Pauses the countdown.
- Start button - Continues the countdown when paused
- Play button - Aborts the countdown and returns to Menu mode when paused. Also the relay will be switched off.

Should looping be off, at the end of the sequence, the system will automatically go into pause mode and show “dONE” on the top display. Also the relay will be switched off.”

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