I have been busy. I have designed a retro look clock which displays the time using four 'wheels' of LEDs arranged in groups of ten. Each LED therefore represents a value from zero to nine, with the wheels indicating from left to right, Hours tens, Hours units, Minutes tens and Minutes units.
As each wheel has more digits than needed for a time display (apart from the Minute units) the display is animated each second by sequentially lighting each LED across the display before settling and displaying the current time again. At 27 seconds, for 5 seconds, the date and month are displayed, with no animation for the five seconds to differentiate between the time and date.
I was inspired by the old Dekatrons I saw on the WITCH computer at the Museum Of Computing (based at - but separate to - Bletchley Park) last year. These, if you are not old enough to remember, are cold cathode (Valve or Tube) counting devices which when pulsed in the correct sequence move a neon glow forwards or backwards around a circular display which can then be read electronically as well as visually. I've never been able to afford to buy any Dekatrons so have not been able to make a clock using these but thought I might make something similar at some point. I recently read an article in Elektor magazine which showed a capacitance meter which had the display made up of LEDs arranged in partial circles, counting from zero to nine. Inspiration struck, and the next day I started thinking how I might make something similar work.
The design uses four x ten LEDs = forty LEDs. The LEDs are driven using five 74HC595, with each 74HC595 connected to eight LEDs. The 74HC595 are driven using just three lines from the PIC.
The PIC connects to the display, a DS3231 module for the timekeeping, an LCD display to show the time and date to allow the time to be set easily and three buttons to facilitate the time and date setting.
I designed three PCBs for this. The main Dekatron LED array with associated 74HC595. The rear section with the PIC 16F1829, LCD, DS3231 module and 5V regulator. There is also a front panel which fits over the LEDs allowing them to be visible while hiding the components. These three all connect using screws and stand-offs giving a single unit.
The whole thing is powered from a power pack capable of supplying 7V - 12V DC @ 300mA.
I'm going to say, I was super pleased with this project. The whole thing ended up looking just as I'd imagined it would when I designed it, usually I find that compromises in the final build or in the design stage cause the project to slip away from the original concept, in this case that didn't happen.
Eagle schematic, board files and the gerber files for the PCBs. The board files cannot be edited in the free version of Eagle, the gerber files are the files I used to order the PCBs, so should be ready to use.
The clock showing the animated display in real time. There is a longer video which shows the time display for a few seconds, the date is then shown for five seconds before the time display continues.
Very nice!
I like the slowed down one. Fast one is too fast to appreciate.
I remember the neon dekatron from 1974 when i was an apprentice at a tire plant. They had a cutter called a skiver on the tread extruder line that would measure the length of the tread with an optical encoder wheel sitting on the tread feeding the dekatron counter. when it matched the rotary switches below the digits it would send the rotary cutter across making one tread. So the lower digits would spin fast and the larger digits each successively slower. iy was a light show.
Thanks for sharing,
Mike
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
I've updated the source code. I added a 'slow animation' to the clock display. When the time changes from 59 minutes to the new hour, the display slowly rotates all elements then holds them for a few seconds. The effect is similar to the slow motion video I posted.
For demonstration purposes, the animation can be activated by pressing either the up or down buttons when not in adjustment mode.
I also added the option of lighting the LCD backlight under control of the processor. this requires a modification so that pin 8 of the 16F1829 connects (with suitable current limiting resistor) to the Anode of the LCD backlight. The displays I have been using from WinStar have a low enough current requirement that a 220R provides ample illumination and keeps the current from pin 8 well below 20mA. With this in place, the LCD is lit for around 30 seconds following any button press.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
As it is Bank Holiday Monday, we're still in lockdown in the UK and the PCBs for the WS2812 clock are still to arrive...
I've made some minor tweaks to the software for the Dekatron Clock.
If the DS3231 is reporting that the oscillator has stalled, LED number 9 of the Hours will flash off and on every other second. This will provide an indication that the time may not be accurate and should be checked, without the need to check the LCD display on the back of the main clock PCB.
I have added a residual flicker effect to the main display. This is supposed to simulate some flickering of the elements of a real Dekatron where the elements might show some residual illumination after being switched on then off very rapidly. All in my imagination, not having any real Dekatrons. I think it's a neat effect though.
This residual flicker effect can be turned on or off in the adjustment menu.
The showing of the date once a minute (at 27 seconds) can now be turned on or off in the adjustment menu.
Here is a video which shows the hourly animation in action. Normally it is only shown at the top of every hour but can also be called manually as I do at around ten seconds in the recording. Although you can't really see the residual flicker I added to the unlit LEDs to simulate a real Dekatron being regularly updated, at the end of the slow animation there are a few tenths of a second where only the current time LEDs are on, before the residual flicker is activated. I apolgise for the video losing focus each time the seconds "blip", I have a new 'phone on order and I'm hoping it will be able to keep focussed on one thing, for longer than my current one.
I have been busy. I have designed a retro look clock which displays the time using four 'wheels' of LEDs arranged in groups of ten. Each LED therefore represents a value from zero to nine, with the wheels indicating from left to right, Hours tens, Hours units, Minutes tens and Minutes units.
As each wheel has more digits than needed for a time display (apart from the Minute units) the display is animated each second by sequentially lighting each LED across the display before settling and displaying the current time again. At 27 seconds, for 5 seconds, the date and month are displayed, with no animation for the five seconds to differentiate between the time and date.
I was inspired by the old Dekatrons I saw on the WITCH computer at the Museum Of Computing (based at - but separate to - Bletchley Park) last year. These, if you are not old enough to remember, are cold cathode (Valve or Tube) counting devices which when pulsed in the correct sequence move a neon glow forwards or backwards around a circular display which can then be read electronically as well as visually. I've never been able to afford to buy any Dekatrons so have not been able to make a clock using these but thought I might make something similar at some point. I recently read an article in Elektor magazine which showed a capacitance meter which had the display made up of LEDs arranged in partial circles, counting from zero to nine. Inspiration struck, and the next day I started thinking how I might make something similar work.
The design uses four x ten LEDs = forty LEDs. The LEDs are driven using five 74HC595, with each 74HC595 connected to eight LEDs. The 74HC595 are driven using just three lines from the PIC.
The PIC connects to the display, a DS3231 module for the timekeeping, an LCD display to show the time and date to allow the time to be set easily and three buttons to facilitate the time and date setting.
I designed three PCBs for this. The main Dekatron LED array with associated 74HC595. The rear section with the PIC 16F1829, LCD, DS3231 module and 5V regulator. There is also a front panel which fits over the LEDs allowing them to be visible while hiding the components. These three all connect using screws and stand-offs giving a single unit.
The whole thing is powered from a power pack capable of supplying 7V - 12V DC @ 300mA.
I'm going to say, I was super pleased with this project. The whole thing ended up looking just as I'd imagined it would when I designed it, usually I find that compromises in the final build or in the design stage cause the project to slip away from the original concept, in this case that didn't happen.
Last edit: mkstevo 2020-02-17
Eagle schematic, board files and the gerber files for the PCBs. The board files cannot be edited in the free version of Eagle, the gerber files are the files I used to order the PCBs, so should be ready to use.
Last edit: mkstevo 2020-02-17
Source code.
Minor correction and header file requirement removed.
Last edit: mkstevo 2020-05-25
The clock showing the animated display slowed significantly.
The clock showing the animated display slowed by a factor of five.
The clock showing the animated display in real time. There is a longer video which shows the time display for a few seconds, the date is then shown for five seconds before the time display continues.
YouTube_Video
Last edit: mkstevo 2020-02-17
Very nice!
I like the slowed down one. Fast one is too fast to appreciate.
I remember the neon dekatron from 1974 when i was an apprentice at a tire plant. They had a cutter called a skiver on the tread extruder line that would measure the length of the tread with an optical encoder wheel sitting on the tread feeding the dekatron counter. when it matched the rotary switches below the digits it would send the rotary cutter across making one tread. So the lower digits would spin fast and the larger digits each successively slower. iy was a light show.
Thanks for sharing,
Mike
Love those Dekatrons! Always wanted one, could never afford one! This may not be perfect, but I am pleased with it.
Thanks for your kind words.
Very nice. A great use of the DS library.
Thank you for posting!
I've updated the source code. I added a 'slow animation' to the clock display. When the time changes from 59 minutes to the new hour, the display slowly rotates all elements then holds them for a few seconds. The effect is similar to the slow motion video I posted.
For demonstration purposes, the animation can be activated by pressing either the up or down buttons when not in adjustment mode.
I also added the option of lighting the LCD backlight under control of the processor. this requires a modification so that pin 8 of the 16F1829 connects (with suitable current limiting resistor) to the Anode of the LCD backlight. The displays I have been using from WinStar have a low enough current requirement that a 220R provides ample illumination and keeps the current from pin 8 well below 20mA. With this in place, the LCD is lit for around 30 seconds following any button press.
As it is Bank Holiday Monday, we're still in lockdown in the UK and the PCBs for the WS2812 clock are still to arrive...
I've made some minor tweaks to the software for the Dekatron Clock.
If the DS3231 is reporting that the oscillator has stalled, LED number 9 of the Hours will flash off and on every other second. This will provide an indication that the time may not be accurate and should be checked, without the need to check the LCD display on the back of the main clock PCB.
I have added a residual flicker effect to the main display. This is supposed to simulate some flickering of the elements of a real Dekatron where the elements might show some residual illumination after being switched on then off very rapidly. All in my imagination, not having any real Dekatrons. I think it's a neat effect though.
This residual flicker effect can be turned on or off in the adjustment menu.
The showing of the date once a minute (at 27 seconds) can now be turned on or off in the adjustment menu.
Here is a video which shows the hourly animation in action. Normally it is only shown at the top of every hour but can also be called manually as I do at around ten seconds in the recording. Although you can't really see the residual flicker I added to the unlit LEDs to simulate a real Dekatron being regularly updated, at the end of the slow animation there are a few tenths of a second where only the current time LEDs are on, before the residual flicker is activated. I apolgise for the video losing focus each time the seconds "blip", I have a new 'phone on order and I'm hoping it will be able to keep focussed on one thing, for longer than my current one.
https://youtu.be/Vtyn6-8d2KQ HQ YouTube version of the same video.
Last edit: mkstevo 2020-07-12