Posts tagged ‘7 Segment’

Reverse Engineering of BK Precision 1696 Switching Power Supply’s LCD Protocol

As mentioned in my previous post, besides the broken LCD there was also an issue with the power supply portion of the unit and the output voltage was clamped at around 10 to 11V. The digital circuitry portion however seemed to be intact. Unfortunately since an identical LCD is virtually unobtanium, I thought I’d reverse engineer the LCD protocol so once the power supply is fixed I can fix the display by hooking up a different LCD. Continue reading ‘Reverse Engineering of BK Precision 1696 Switching Power Supply’s LCD Protocol’ »

Digital Metronome — Revisited

Last year, I wrote about a simple digital metronome project. While the device worked pretty well there are a few changes that are to be desired. Continue reading ‘Digital Metronome — Revisited’ »

An 8-Digit 7 Segment Display

I built a 4-digit 7 segment display last year. In that design, I used four 74HC595 shift registers to drive the four individual 7 segment displays, with one for each digit. So when I wanted to build an 8-digit display, I thought about using the same design with eight 74HC595s at first. But it seemed that the soldering would be a lot more challenging on the prototype board as there will be 8 chips and 64 resistors to solder. Continue reading ‘An 8-Digit 7 Segment Display’ »

4 Digit 7 Segment Display Using Arduino

I was inspired by Paul’s 7 segment display and decided to build one myself. He used 4 common cathode 7 segment displays. In his original schematics, all the segments within a display shared one current limiting resistor which unfortunately affect the display brightness when different numbers of segments are lit. I happened to have two common anode dual 7 segment displays (QDSP-G545) so I decided to use them and four 74HC595 shift registers to build a four 7-seg display. Realizing that other people might be using either common anode or common cathode displays, I also built a library that can be used for either case. Continue reading ‘4 Digit 7 Segment Display Using Arduino’ »