Usage Guide

Setting the Time

To set the time, simply press the HOUR and MIN buttons. You can hold the buttons to make the numbers advance automatically. When setting the hour, the LED marked PM will indicate that the hour is PM. (The PM LED is only lit when setting the time and alarm because it is quite bright and distracting.)

Setting the Alarm

Hold down the ALARM button (lower left corner of board), then use the HOUR and MIN buttons to set the alarm time. The LED marked PM indicates if the alarm time is PM.

There are 3 alarm modes, OFF, ON, and DEFUSE. To cycle through the alarm modes, hold the ALARM button, then press the large red DET button. Two LEDs indicate which mode the alarm is in. One LED is near the ALARM button, the other is near the large red DET button.

LED indicators alarm behavior alarm OFF alarm LED off, DET LED off alarm is off alarm ON (normal mode) alarm LED on, DET LED off alarm will beep alarm ON (defuse mode) alarm LED on, DET LED on alarm will beep a few times, then 10 second countdown sequence begins

Turning off the Ringing Alarm

When the alarm is beeping (normal mode), turn the alarm off by pressing the alarm button.

For snooze, press the red DET button. Alarm will ring again in 9 minutes.

If you are using the “defuse” alarm mode, you can try to defuse the clock by cutting the right wire. Otherwise, the 10 second countdown will reach 0 and the device will “detonate”.

Starting the Countdown Sequence

Press the red DET button to start a 10 second countdown sequence. If you want the countdown length to be longer, press the HOUR and MIN buttons before releasing the DET button. You can set the countdown to be up to 99 minutes and 59 seconds.

During the countdown, choose the correct wire to defuse the device. One wire stops the countdown safely, two have no effect, and one will cause the device to detonate immediately. The role of each wire is assigned randomly each time the DET button is pressed.

New features in V2: If you have version 2 of the Defusable Clock, you may adjust the countdown duration up or down. When holding down the red DET button, you can use the MIN and HOUR buttons to increase the countdown time. To decrease the countdown time, also hold the ALARM button while holding down the DET button. When you release the DET button, the countdown starts and this countdown value is the new default. It is written to EEPROM and is saved even if the power is disconnected.