This is a sub-$10 (assembled) shield featuring a 4-digit 7-segment LED display that can be connected to virtually any microcontroller. Schematic and BOM are available, and making Arduino sketchs available is the next step on its journey.
Components
1×
74HC595
Shift register
1×
PCB
Board and schematics avaiable in the links section
4×
BC557
PNP transistor
1×
Ceramic capacitor
100nF/50V
1×
7 Segment LED display
COM-09483 or equivalent, common Anode 4-digit, any color
I am a very active member of the "Arduino Brazil" group on Facebook (we are already 13k+ members!!); you guys have no idea on how much is done in that group, and how much I learn from there every day.
One of the members I recently met gave me the idea of making a 4-digit 7-segment "shield" that could be used independently of Arduino (featuring a different form factor). This guy resells in Brazil stuff he buys from Aliexpress, so I assume he knows what he wants (and knows what is available out there).
After a bit of [Google Images] research, I convinced myself that the available shields for that product were virtually inexistent, and decided to give it a try on making my own product.
So what you guys are going to see here is the making of a 4-digit 7-segment LED display using the well-known 74HC595 shift register (for pin saving reasons). My main goal is to sell some of those boards (when ready to it) and make a bit of money. But of course everything will be open-source, since I am not going to reinvent the wheel here.
I went through this exercise with my GPS clock project. For me, the solution was the MAX6951. It's perhaps a little pricey, but I found it quite easy to work with. Since you have only 4 digits, the 6950 would be for you.
I went through this exercise with my GPS clock project. For me, the solution was the MAX6951. It's perhaps a little pricey, but I found it quite easy to work with. Since you have only 4 digits, the 6950 would be for you.