In my various projects, I've always wanted to use 7-segment displays to show numbers. They're cheap, and easy to read at a glance. I've not been able to implement them, however, due to the number of pins it takes to drive them. For 4 decimal digits, It would take ~32 i/o pins, not to mention the processing time to derive which pins to drive. I've seen some bcd to 7-seg driver chips, but this would only cut the number of pins in half, and still require processing time. I know 'scanning' implementations exist to cut the pins further, but without more dedicated chips, this would load the microcontroller down significantly.
What I would love to see SFE carry, is a module that takes TTL serial bytes and displays the decimal equivalent. That's only one i/o pin to take care of that task. I've looked for a chip that offers this, and i've yet to find one, but I would have to imagine it exists.
If not, I'd love to see SFE develop one. It could even take the form of a "backpack" like they use for the 44780 lcd's, with a board to hold the 7-seg displays, and all the drive hardware on the back of the board. The only wires that would be needed are ground, power, and signal. My idea assumes only 4 digits, but in reality, any number could be used. Since there would always be numbers that could be sent, but are too large to display(10000-32767 for 4 digit setups), you could reserve certain large numbers for configuration options. For example, to toggle individual segments, set the number of display digits(if the end user wants less than what the unit is capable of), set baud rate, toggle separate general-purpose outputs, or to set brightness. I have a feeling that a product such as this, assuming it does not already exist, would fill a large niche of easy to implement, low cost displays.
Thanks for you time.