Diorama: Power Supply Completed
Following some experimentation, the main power supply circuit board has been completed. The supply is soldered to a piece of copper perf board that has been mounted on the back of a facia where the power supply is plugged in. The facia has been bolted in place in the rear left hand corner of the diorama.
Power enters the diorama via a 2.1mm × 5.5mm power socket. A bridge rectifier is used to enable both centre positive and centre negative supplies to be used.
A red LED mounted above the power socket illuminates when power is connected.
A voltage regulator is used to provide a 5V supply for the microcontrollers, LEDs and motors. There are output pins making available 7.9V and 5V, along with associated ground pins.
Here is a composite photo of both sides of power supply circuit board:
The following photo is a composite photo showing both sides of the power input panel, with the power supply circuit mounted on the rear. Note the panel wiring and the power supply board were not yet connected in this photo:
The pins shown in the rear photo are, from left to right:
- A pair of polarity agnostic 9V input pins.
- A pair of pins to connect the power indicator LED (7.8V and GND). Note that the LED's current limiting resistor was soldered directly to the LED, under the heat shrink.
- A pair of 7.8V power pins for connection to other circuit boards that may require the maximum available voltage.
- A bank of five GND pins for connection to other circuit boards that may require them.
- A bank of three 5V pins for connection to other circuit boards that may require them.
Since the above photo was taken the power supply socket has been connected to the 9V input pins and the power indicator LED has been wired to the dedicated 7.8V LED pins.
The schematic diagram of the power supply is shown below:
