Projects by PC Designs: Timer Inside/Front View

This view shows the inside, the front panel and the inside of the back panel. Again, the back panel was made as a plug on assembly. This allowed each part to be made separately and then assembled into the complete unit. In this view the beige colored main board is readily visible, as is the battery holder. The main board was used to route signals to and from the various components, and also included the power supply and low battery detection circuitry. An A/D input ton the microprocessor was used to measure battery voltage and determine when it was low. The power supply used a MAX666 regulator in a novel configuration that allowed it to function with only 200 mv of headroom.

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