Remote thermometer - display unit

This unit is constructed as a hand-held unit with a stub aerial. The LED indicates when the unit is awaiting a data transmission. One of the decimal points on the display is used to indicate reception status. To save power the display unit is only alight for about one and a half seconds after the display button has been pressed. The maxiumum voltage for the receiver module is 5.5V, so the unit is powered by NiCad AA cells (about 4.8 volts).