Box and power supply for a pager I have boxed one of the modified pagers on this site and added a power supply. Schematic diagram of the 1.5 Volt power supply
The power supply is based on the LM317. I have used the low power version: a pager consumes just a few milliamperes. The input voltage can be anything between 4.5 to 15 volt, e.g. from a cheap wall wart. With the potmeter, you can set the output voltage between 1.3 V and 1.8 V. Diode D1 prevents the IC or the pager from being damaged if the + and - of the adapter are swapped inadvertedly. A larger schematic diagram can be found here   The power supply on perfboard
Boxed pager and power supply
The power supply can be built on a small piece of perfboard. I used some isolation tape between the power supply and the pager to prevent short circuits. Two holes are drilled in the enclosure: one for the 3.5 mm socket and one for the adapter plug. I used a PCB mount power socket and glued it to the enclosure using PVC glue. To create more space if needed, the pager's vibrator motor can de removed. If required, you can connect a LED power indicator to the power socket using a 1 k resistor.  The result is a neat compact box, that can be connected to a 2 level interface or to your PC's soundcard.. Just to make sure: use a plastic enclosure. If you use a metal box, the pager's reception will be worse because the antenna is shielded. The result
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