Custom BCD to 7-seg Display PCB

January 07, 2017

Electronics
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Description

The idea of anyone being able to design and print their own circuit board would have been nearly infeasible a few decades ago. Now, many PCB manufacturers are able to produce custom boards in a matter of days. The purpose of this project was to get familiar with the process of designing and printing custom PCB boards. I wanted to create a simple circuit that my Arduino could interact with. I ended up choosing to create a “BCD to 7-Seg Display” circuit, and then design a custom PCB board to house the components.

Prototyping

First, I needed to prototype the circuit. I found a BCD to 7-Seg converter IC (NTE 7447). This particular component had pull-up resistors for the A-G pins, so I had to use a common anode 7 Segment display. After acquiring the components, I wrote a small program on my Arduino Leonardo to send binary values over 4 pins to the IC, which lit up the 7-Seg display to the corresponding decimal value.

proto

Design and Schematic

Next, I learned a bit about the CadSoft™ EAGLE software, which is used to create circuit schematic and board files. I used the software to create an initial schematic, and then made the board design, based off the schematic.

schematic

Assembly and Final Product

After processing the board file, I exported the necessary files for the PCB manufacturing process. I chose to use PCBWay to manufacture my boards, which took about 2-3 weeks to manufacture and ship (not bad, given that the PCBs are produced and shipped from a manufacturer in China).

board

After getting my board, I soldered the components together and tested my board. It worked just as well as the prototyped circuit, and I was very happy that my first endeavor turned out a success.

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