Mechanical Design

   This device has three sub-assemblies inside and the display is installed on top of the enclosure.

 The BME680 Environment Sensor is underneath the screen on the outside for ventilation. There is an air gap between it and the display for thermal insulation.

The Teensy is plugged into a breadboard. The Picaxe, DC-DC converter, the two LEDs and the charger are on one circuit board, and the receiver on the other. The 18650-size battery has a connector on a pigtail. It is restrained by barriers and an elastic button on the closure.

All interconnections are made with jumper cables. Visible are the pushbutton and two LEDs. A blue one flashes on receipt of a message. The other has red and green LEDs. The red is connected to the pushbutton, the green to the 5V output of the DC-DC converter. An exception is the RTC battery connections which goes directly from the Teensy to a connection next to the battery connector on the Power sub-assembly.

For the fall ’23 version the antenna was re-routed directly out of the enclosure for better reception.