Why? Well, it would appear that I just can’t get enough of old display technologies! With the amazing help from my good friend Grahame, I cajoled him into helping design a series of clocks using old display tubes (VFD, nixies and dekatrons) and only TTL logic with about as many knobs, switches and LEDs as possible. It also has one more digit than some may deem necessary. This followed on from his rather remarkable use of TTL to drive a cathode ray tube, resulting in the SCTTL clock. I think the end result turned out quite nice and it’s certain to attract people’s attention when on display. The clock also follows some of the design aesthetic of the KoolKlox.
Offered as both a kit of parts and also as a complete clock, if you like a lot of soldering and learning how TTL logic works, then this is for you. The end result is visually stunning and it also tells the time! At the heart of it is a 32.768KHz oscillator (TCXO) that is used as the time base and a sequence of logic chips to derive 2, 1 and 0.5 Hz frequencies to drive the various parts of the clock. The binary counters for the hours, minutes and seconds are all illiuminated by LEDs (brightness controllable) and the VFDs are backlit with controllable red, blue and green LEDs, all with pots so you can dial in your favo(u)rite backlighting colo(u)r!. Here is a list of all the ‘twiddly’ bits on the side of the clock…
- Tube Brightness – does what it says!
- 1/10th Secs On-Off – For those that don’t like the dance of the 1/10ths of seconds, feel free to turn it off!
- Colon On-Off-Flash – Three-way switch to make the DM160 tubes flash according to the frequency set by the X1 jumper (0.5, 1 or 2 Hz), stay static or turn off.
- Sec. Colon On-Off-Flash – Both the YS27-3 and IV22 tubes contain a decimal point, this switch controls this the same way as the Colon On-Off-Flash switch.
- All Segment Test – Press this button to illuminate all the segments on every VFD tube to test.
- Red LED – Controls the brightness of the RED LED.
- Green LED – Controls the brightness of the GREEN LED.
- Blue LED – Controls the brightness of the BLUE LED. Adjusting all three of these allows your own colour palette of backlighting!
- Zero/Secs Hold – Resets the seconds VFDs to zero and keeps them there until you release the button.
- Minutes Set – Use to set the correct Minutes time.
- Hours Set – Use to set the correct Hours time.
- 12/24 Hr – Toggle between 12 and 24 timekeeping. You may need to cycle through the hours once to reset the hour counters correctly after changing.
- Binary LED Brightness – Controls the brightness of all the LEDs on the clock PCB (Binary counting, PIR and PLL Lock).
A complete kit manual is available for download and the design is Open Source. Due to shipping restrictions, the NiMH AA batteries needed for the backup supply cannot be provided with the kits, but they are readily available from online retailers.
Prices
- Kit of parts w/o battery backup – $445
- Battery backup kit – $100
- Prebuilt clock w/o battery backup – $550
- Prebuilt with battery backup – $650
The clock uses a 24V 2A DC power supply and all kits and clocks shipped in the USA include one. International customers will need to find one locally. Please contact me as usual if you have any questions and as always, sales in CA will be subject to sales tax.