Replacing old LCD or VFD displays using an emulator/microcontroller?

[lordvader88]

I'm thinking of mainly of 7-segment displays but that other kind too (Vacuum florescence display) ?

If you have some old equipment with a broken display, but the chip still works, how hard is it for someone with programing skills, have a micro-controller like Ardino basically translate the signals and run a nice big modern LCD ?

Or if the display chip is broken, how hard is it to take it's input with a MC (or some FPGA magic I don't know about) and basically emulate what some 1970s 1980s display chip should be doing, then feed it to any old display ?

Or if u just want to add a nice big modern LCD, even if it only shows the main numbers, and not all the side info on screen. And so hacking that onto an old bench DMM for example ?



And what about just feeding right off the original 7-seg display inputs, and just adding a big $2 one off ebay (or whatever they cost ). Is that an easy mod ? I don't mean the original chip would have to drive the new LCD, just reading whats going to it and driving the new 7-seg display.

[sokoloff]

Some good discussion here where someone made an LED replacement for an LCD on a 3457a.

https://www.eevblog.com/forum/projects/led-display-for-hp-3457a-multimeter-i-did-it-)/msg1345741/#msg1345741

[james_s]

It can range from trivial to quite involved depending on the details. The first thing I'd suggest doing is take a look at what's driving the display, then you can decide whether it's easier to try to repurpose the existing driver or build something new that picks up the data being sent to the original driver. Quite a few displays will have a driver that uses SPI or something similar although in lower cost equipment the display may be driven directly from a custom microcontroller.