Flashing synchronars

[paulmondays]

This is probably nothing new to the experts out there. I've been shaking Pulsars up and down in darkened rooms for a while now, transfixed by their on - off trails of red LEDs. It can be quite relaxing. I've noticed how the whole display switches on and off.

I've recently tried this with a Synchronar and noticed things are a little different: instead of the whole display switching on and off it appears that the individual digits of the display are flashed up in sequence. This must be a more efficient power saving feature than the Pulsars.

This may be interpreted as supporting evidence for suggesting independent but parallel development of LED watches by both Pulsar and Mr Riehl. Or not. As usual everything's down to interpretation...

[Higgie]

Take your digital camera, set the shutter speed at about 1/250th second and watch the display of your camera.
You will notice that both the Pulsar and the Synchronar are multiplexing, but the synchronar in about double the speed of the Pulsar.

[rewolf]

wikipedia has a nice article on display multiplexing http://en.wikipedia.org/wiki/Multiplexed_display
Don't miss the "Break up" paragraph :wink:
Higgie's method is good to visualize the type of multiplexing ("muxing"). What you observe is interference between the muxing frequency and the camera's frame frequency (same affect as wheels in movies appearing to turn too slow or even backwards).
There are many ways to mux 28 LEDs. E.g. digit-wise (4x7), segment-wise (7x4), or some weird "cross-digit" scheme like 6x5.
The Synchronar seems to mux digit by digit.
The Majestyk e.g. muxes "all over the place" (don't know the exact scheme). If you move it fast it shows weird patterns.

[Synchroserious]

Well yes we are looking at lights turn on and off so fast that the human eye ordinarily does not catch it.This thread indicates to me that reading the frequency from the display via fiber optic cable signal to Frequency counter involves different formulas for different makes of LED.

The Synchronar has 9 double wire bonded segments in the first digit,8 on the second and 7 on the two on the right.It starts to Mux? by lighting up each segment individually on the first digit then moves to the second,third and fourth before starting over again.The fiber optic cable see,s the slight difference in mux speed created by each individual QC and that,s how Synchronars have been set to their own unique Speed #. This is all in an effort to reach 32,768 instead of 32,768.5 or 32,765.5.

The only variance is the temp difference of the watch while being tested versus in the field.In other words Temperature is a variable not only with accuracy of any given Q-Crystal but on how many times in one second each segment winks at you :wink: This is the case on the Synchronar anyway and I have no clue how this applies to other LED watches.


If all this flashing is what people want then I feel better about announcing my prototype with extra LED that beams out the back of the case.This is for the one that can be easily opened for battery drop in I have been working part time on.

[Synchroserious]

Correction. Before I create confusion that I so much desire to eliminate it should be noted that the MK I and MK II displays were pre fab from Monsanto with the standard 7 segments on each digit as there was no DOW on them.However when RTC took over IN 77 they began making their own in house displays(double wire bonded for each segment) for the MK III with DOW requiring two extra segments down the middle of the first digit to form a T for Tuesday and Thursday.Then on second, one additional or 8 segments were required to complete the R for FR-IDAY.

If you add the two wire bonds for each colon dot there is a total of 66 wire bonds.

[Fitron]

I feel better about announcing my prototype with extra LED that beams out the back of the case.This is for the one that can be easily opened for battery drop in I have been working part time on

Oh c'mon Howard, you can't say this and leave it at that. I'd never buy a Synchronar that's sealed but this is interesting to say the least.......

[Synchroserious]

If you don't want time sealed in a capsule as proof that you never re placed the batteries along with a multitude of other advantages then I present one that has an extra drain but cool factor with a need to replace the batteries and of course lose shock,temp and waterproof qualities if that is what your into.

[paulmondays]

Mmmm I'd like to clarify something if possible. Pulsars appear to switch their displays on and off in entirity. The Synchronar seems to light up one digit at a time. Is this the case or is it that my simple monkey brain is not capable of perceiving the fact that the Synchronar is doing the same as the Pulsar only twice as fast?

It's not important I'm just curious. Howard seems to be indicating that the Synchronar does light up a single digit at a time, but I don't want to put any words in Howard's mouth. I'll leave the technical side of things to those further along the evolutionary path.

[Synchroserious]

Not sure about the twice the speed thing,which was a basic guesstimate from Higgie.The digits are the 4 main characters but each one of them contain at least 7 segments.The # 8 needs all seven segments lit on one of the four digits while a 1 reguires only two segs lit.


So I still have no comment about speed comparisons to a Pulsar but I am saying the Synchronar has quite a few more transistors on the chip for that time in history. It muxes each segment one by one starting on the first of four digits from left and then starts to mux all segments on the next digit right on down the line until it is time to start over again.

Keep in mind you will not see the muxing of a segment that is not required to be lit,only the fiber optic eye connected to a frequency counter knows precisely when it would have been lit if it was 18:08 instead of__ 1:01.
Then of course you have two colon dots divided between the four digits which are not muxed in synchronicity with the segments but become lit when everything else is muxing with osc running.Hope this helps and keep in mind we all sometimes mistakenly have called a digit a segment and visa versa.