ALS324A LED (1980) on a new clock (2024) pt.1

Watch the USSR Sojus space ship clock disassembly, probably the same type of LED
https://youtu.be/JBIhzEZkWEA?t=880

The updated printable files allow mounting the TM1637 directly to it own front bezel.
Nevertheless the TM module can not be used with the code provided for the Max7219.
The used ESP-12 modul can drive a TM1637 LED module directly but it needs different code.

New housing design made https://youtu.be/8Ug_NvnaWMg
Available new compatible comCathode Kingbright SC03 LED, typical brightness in milliCandela
SC03-12HWA red 0.6
SC03-12GWA green 1.8
SC03-12YWA yellow 1.8
SC03 12EWA super red 1.8

printable parts
- small LED clock housing V2
- ALS324 LED pcb front mount piece V2
- TM1637 LED modul front mount piece V2

- code, the Arduino sketch & needed libraries
- pcb files
- documentation

For the wiring read below or see the Arduino sketch.

New display pcb for using old and new LED
This is a pcb suitable for small electronics projects like watch, etc.
On the display pcb 5 pieces of old ALS324A (cC, red) made in the USSR in the 1980's or new Kingbright SC03-series LED (see the list above) can be seated with no problem.
When using the old LED with wide flat pins, PLS solder on pcb or take the old style 14 pin DIP IC sockets (no machined pins).
The USSR made LED have a clear plastic case but no light guiding channels.

LED driver Max7219
Lets talk Max7219 features be cause many poeple do not know or do not care.

I go in detail on features almost NOBODY talks about.
Well, the Max7219 does multiplexing on the digits and segments.
But its done in a different way compared to other methods that can be found on almost every other esp. microcontroller based LED clock.
On the Max7219 (even on the faked IC the usual suspects put on chinese made crappy products) the brightness can be set to 16 different levels, based on the nominal current set by a resistor Rset.

Eventually the LED brightness depends on combining the set current & the value "level" in the Arduino program (1-15) then.
The ON-OFF sequence described below is being performed for each of the 7 segments independently.
Common is the periodical switching ON/OFF (duty cycle) set by the value stored in a certain register controlled by the "level" value.

Measurements I have taken (segment current, segment ON-OFF cycling)
At Rset resistor value of 10k the voltage drop on a shunt resistor of 10.8 Ohms measures 450 mV. That means the peak current is app. 44mA

Brightness levels
When set to "1" the ON-duration is 18.9us.
When set to "15" the ON-duration is 200us followed by a brief OFF blank period.
That almost equals always ON = DC current. Then driving 44mA is out of spec. of the ALS324.

How to operate the Max7219 & ALS324A LED
1. methode
Probably driving 40mA half the time could do. To be safe set the brightness level register to 7 or 8.
2.methode
By driving 20mA all the time it should safely fit the maximum ratings on the ALS324A.
For that goal the resistor Rset needs to be adjusted.
See the table 11 on the Max7219 document.

############ Make the clock ############

Get the documentation and the files for making. https://drive.google.com/drive/folders/1AtvjuW3SOb1PjTGbq6m-BTsheGvWOHpJ?usp=sharing

############ Arduino code & wiring############

Initial code (with no wiring diagram, no schematics) was provided by the original maker.
Watch the video, link below.
I have put on a few modifications and slimmed it down, removed unneeded portions.

# the Max7219 module and the Wemos D1 Mini #

Wiring
According to the Arduino sketch I have uploaded.
Max Wemos
DIN D5
CLK D7
CS D8

LED pcb Max7219 pcb pin header, pin mumbers and positions go counterclockwise (top view)
Dig1 M1 pin1 left row pos No 1
Dig2 M10 pin12 right row pos No 4
Dig3 "-" pin8 left row pos No 8
Dig4 H1 pin14 right row pos No 6
Dig5 H10 pin9 right row pos No 1

Seg a pin3 left row pos No 3
Seg b pin4 left row pos No 4
Seg c pin10 right row pos No 1
Seg d pin6 left row pos No 6
Seg e pin11 right row pos No 3
Seg f pin15 right row pos No 7
Seg g pin16 right row pos No 8
------------------------------------------------------------------
Put to good use an old display by making a small clock using the little different ALS320 LED
"Маленькие часики на ESP8266 MAX7219 АЛС320".
https://www.youtube.com/watch?v=TVUcs5RSl3w

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