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8 Segment Numeric DIsplay

A 10W/digit numeric display to show numbers in any room. Designed for MIT 2.007's Spring gameboard.

AssembledView

2.007 Display Display showing 2.007

xxxx Display Display showing xx xx

Interactive BOM for LED Display

Interactive BOM for LED Display Controller

Schematic for LED Display

Schematic for LED Display Controller

The display is a 65mm x 102mm single layer aluminum PCB. It has a 1x20 SMT male header in order to connect a driver board. The display requires active cooling for duty cycles above 50%.

The driver is a 75mm x 32mm double layer FR4 PCB. It relies on a 74HC595 shift register to drive a chain of displays using a single data stream. The driving microcontroller can send 3.3V or 5V logic. The logic level is set by the reference voltage on the input. The driver has an onboard buck converter to create the drive voltage of the display. The board can receive 7-28VDC (Peak current draw is 10W/Vin).

Driving Logic

  • Pull nCLR high in order to prevent an accidential clear
  • Use SRCLK and SER to send a data packet to the first number's data packet on the right (with LSB first)
  • Repeat sending data until all numbers are sent.
  • Pulse RCLK to push shifted bits into the outputs
  • Use PWM on nOE to adjust the display brightness. Note: The brightness will lower with higher duty cycles.
Number to display Data packet
0 0b10111011
1 0b00000011
2 0b00111010
3 0b00011110
4 0b01000110
5 0b01011100
6 0b00101110
7 0b00110010
8 0b01111110
9 0b01110010

Ordering the LED Panel Parts

From Digikey: quantities are for 1x LED panel.

1x S1113E-20-ND

In addition,

Red:

  • 20x 90-JE2835ARD-N-0001A0000-N0000001TR-ND

  • 10x RMCF2512JT18R0CT-ND

Blue:

  • 20x 90-JE2835ABL-N-0005A0000-N0000001CT-ND

  • 10x 118-CRM2512-JW-6R8ELFCT-ND

Yellow:

  • 20x 90-JE2835APA-N-0001A0000-N0000001CT-ND
  • 10x RMCF2512JT18R0CT-ND

Green:

  • 20x 90-JE2835AGR-N-0002A0000-N0000001CT-ND
  • 10x RMCF2512JT10R0CT-ND

Resistance values for colors:

  • Red: For 140mA (25.2lm/led) use 18R
  • Amber: For 140mA (24.8lm/led) use 18R
  • Green: For 140mA (65.5lm/led) use 10R
  • Blue: For 140mA (16.5lm/led) use 6.8R

Ordering the LED Panel Controller Parts

Digikey Parts

Quantity Digikey PN Description
1 1189-3657-ND 120uF/35V Capacitor
1 399-ESK337M016AE3AA-ND 330uF/16V Capacitor
1 F3375CT-ND 2A Polyfuse
1 455-1849-ND JST PA 1x04 RA Housing
1 455-2753-ND JST PA 1x04 Connector
4 455-1325-1-ND JST PA Crimp
1 1292-WR08X000PTLCT-ND 0805 Jumper

Amazon Parts