The display should now run brighter and with less flicker. I also took the opportunity to completely rearrange the internals to make it easier for constructors to make code changes for their own requirements.
I've just released new PIC firmware for the PIC Digital Thermometer & Clock project that was originally published on 3rd September 2011.
The display should now run brighter and with less flicker. I also took the opportunity to completely rearrange the internals to make it easier for constructors to make code changes for their own requirements.
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![]() I’ve been experimenting with using a PIC to control long chains of 7-segment LED displays, and to find an approach that I can use to replace the obsolete TIL311 displays. To that end, I’ve created a tech article that describes a simple way to do this. My prototype was 24 digits long; long enough for most applications I think, but could be extended. It’s all done with a PIC18F25K22 running from its own internal oscillator, accepts data from a serial device at 9600 baud, and supports 0 to 9, and A to F value display. The code is written in AMICUS18 BASIC which is free so you can change the software to suit your own application. All the fully documented source code is supplied as well as a schematic of the circuit. The picure above shows 24 digits (6 x 4 digit modules). The display modules each contain a 4 x 7 segment Common Cathode display, a DIL resisor pack on the modules right-hand side, and there are 4 n-channel SMT MOSFETS underneath. The advantage of using modules on breadboards is the vast amount of time, and wire that's saved. You can throw a quick circuit together in no-time if you already have the modules pre-built. It also saves a lot of breadboard space. I completed work on a new Nixie Clock at the weekend; this one’s for me. I already had the tubes as I’d bought a batch of 17 off Ebay a while ago and whilst I used 6 for a friend’s clock, the rest were just sitting there begging to be used.
The design is basically the same as the original but I did take the opportunity to update PCBs in a couple of places and add some expansion capabilities. I’ll be publishing the construction details here soon… watch this space. |
AuthorA software and hardware engineer who loves retro computers. Archives
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