LED Scoreboard

This project is a remote-control LED scoreboard, made using a custom PCB.

Demo

Design

The scoreboard has three components - the 'brains', the display faces, and the remotes. All three pieces were combined into one PCB, which was snapped into the individual components.

• The central piece is the 'brains'. It consists of a Raspberry Pi Pico W and four 26-pin connectors, into which the faces can be attached. The Raspberry Pi processes the incoming IR signal, and updates the state of the display accordingly. Each of the four faces displays the same information, and can be hotswapped. The Pico is powered directly by a USB cable, and powers the faces.
• Each of the display faces has two 4-character 7-segment LED displays, two 10-segment bar LEDs, and an infrared detector. The faces are connected to the central piece using a right-angle 26-pin connector. This means that faces can be added or removed at any time, even while the scoreboard is in operation. There are 14 pins for the anodes of the two 7-segment LEDs, 4 pins for the 7-segment common cathodes, 3 pins for controlling the bar LEDs, 1 pin for the IR detector, and 2 pins for +3V and GND. This leaves 2 pins for possible additional features in the future - such as a piezzo buzzer. The 7-segment LEDs are controlled by cycling through the four different common cathodes, and setting the 14 individual segments directly - relying on persistance of vision to make it appear as though all four digits are rendered continuously. The bar LEDs are controlled using a decade counter. The decade counter has ten outputs - exactly one of which is high at a time. On each rising edge to the decade counter the next output is set as high, wrapping from 9 to 0. They also have a reset pin that sets the state to 0. The reset pins for both decade counters are connected, allowing the Pico to reset them to a known state upon startup. All ten output pins are passed into a cascading chain of transistors. Although this seems like a setup that there would likely be an IC for, I was not able to find one. Both clock pins are connected to the Pico. Because the bar LEd has 11 states, but the decade counter has 10, the eleventh state is covered by holding the clock signal high. The IR detector sends any received signal to the Pico's analog input pin.
• The remote has two AAA batteries onboard to provide power. It can send 20 unique signals, using an infrared emitter with 5 buttons and 2 switches. It has a decade counter and a clock circuit onboard to send repeating sequence of 10 bits, encoding the signal. The clock cycles through the decade counter at 1kHz, and the signal sent depends on which button is pressed and the positions of the switches. The 10 bit sequence consists of a 5-bit data sequence and a 5-bit locking sequence, to allow the Pico to locate the beginning of the signal.