I admit it: I'm a total geek. I love electronics, programming, 3D art, vintage Apple hardware, and whisky. I'm always juggling half a dozen projects. I also enjoy documenting it all: my successes, my failures, my experiences... and everything geeky along the way.

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Large VFD Clock - Part II | Kevin Rye.net - Main

Kevin Rye

Geek Extraordinaire. Yeh, I said it.

Large VFD Clock - Part II

This clock prototype is getting pretty big. I need three breadboards to lay everything out, and I still need to add the audio stuff. It's getting pretty messy and since they're sitting on my computer desk, it's getting pretty hard to sit in front of the keyboard.

messyboards

I decided to relocate it to one of my kids' small little fold-up tables to make my life easier. I also took the opportunity to completely rewire the whole clock to maximum the board routing that I'll have to do on the PCB. With the primary hardware pretty much nailed down and the time displaying properly, it was time to push on with the rest of the code.

The good thing about making a lot of clocks is that after a while, writing the code becomes a bunch of cutting and pasting. The code for this clock closely mirrors that of both of my nixie clocks as well as my LCD clock. I just had to make a few small tweaks. After about two hours, I had all the code written for the time mode, date mode, and alarm mode.

In Time Mode, a colon is displayed between the hours, minutes, and seconds. (The ILT1-5 L I ordered for the minutes/seconds colon still has not arrived in the mail yet. For now we'll just pretend it's there.) A PM indicator is also displayed, as appropriate.

lage_VFD_clock_time_mode_001

Pressing the Date Mode button displays the date. The PM indicator is turned off, as well as the top colon indicator. Pressing the Data Mode button again puts you back in Time Mode.

lage_VFD_clock_date_mode_001

Pressing the Alarm button puts the clock in alarm mode. I turn on another indicator under the PM indicator to let you know you're in alarm mode.

lage_VFD_clock_alarm_mode_001

Pressing the Alarm Enable button toggles the alarm on/off. You can enable/disable the alarm in any mode. Another indicator is displayed under PM to let you know that the alarm is enabled.

lage_VFD_clock_alarm_enabled_001

I still have to make some tweaks to the alarm code since the "delay" that's in there interferes with the multiplexing. I'll probably have to change that to a "while" loop. In any case, here it is for now. It goes off for 20 seconds.

Large VFD Clock Alarm Test

I'm still not sure what I'm doing about powering the display filaments. You can obviously see in the above images that the digit on the far left is much brighter than the one on the right. That's because the digit on the right is the one that's grounded. When you power your VFD filaments with DC voltage, there will be a gradual decay in brightness as you move across the display from Vcc to ground. The answer is to power them with AC. I designed a little AC Filament Driver board, but I'm not sure yet how I want to implement it in the final build.

I decided to take a brake from that and start nailing down a PCB with what I have so far. It's looking pretty good. It's going to be huge, and expensive. So I have to make sure everything is perfect. There's nothing worse than throwing a $70 board in the trash.

Screen Shot 2017-07-02 at 4.23.03 PM

I wasn't originally going to mount the boost converter on the board, since I thought that would mean that the board would have to be bigger than it needs to be, but the 60-pin header that I need to connect the displays is pretty much dictating the width of the board. I had the space, so I figured I'd throw it in. All that remains is to route the traces for the filaments, however I end up doing them.

See this project from start to finish:
More VFDs!!!
VFD Breakouts
Large VFD Clock - Part I
VFD AC Filament Driver
Large VFD Clock - Part II
VFD AC Filament Driver V1.1