Tag Archives: ULN2803

72 Channels Serial To Parallel Driver Board Using 74HC595 & ULN2803

72 channels Serial (SPI) to parallel driver board has been designed for various applications. This project can be used as multi Solenoid driver, large size 7 segment display driver, bar graph driver, and LED driver. The project works with 5V logic levels. Output load supply 12V-48V DC and each output can drive 500mA load.

I have used 3 digits 2.3Inch 7 segment displays as an example, this board can handle up to 9 digits. The board can serve many applications like, Stop Watch, digital timer, counter, score board, token display and lot more.

Project built around 74HC595 and ULN2803 ICs, The 74HC595 devices contain an 8-bit serial-in, parallel-out shift register that feeds an 8-bit D-type storage register. The storage register has parallel 3-state outputs. Separate clocks are provided for both the shift and storage register.

72 Channels Serial To Parallel Driver Board Using 74HC595 & ULN2803 – [Link]

Open Badge: The LED Badge

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Rohit Gupta published a new build, the OpenBadge

The major elements on the PCB were:
– LED Matrix
– A MSP430G2553 microcontroller brain
– A ULN2803 Darlington Driver to sink the current
– A USB connector to charge the battery
– A SBW connector to program the MSP430
– A Switch to change the message
– A Li-Ion battery from a Discarded Phone
– Current limiting and Pull up resistors
– Decoupling Capacitors
– A REG1117 Regulator for MSP430

Open Badge: The LED Badge – [Link]