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Trying to fix a Cresta AS-0216 LED text-scroller / marquee (lemmy.staphup.nl)
submitted 1 year ago* (last edited 1 year ago) by [email protected] to c/[email protected]
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i found this lightbox without keyboard as the second hand store. i thought i'd see what i could do.

There's hardly any info on the Cresta AS-0216.

The websites i found, looking like the same (or similar) device;

There's a blog about a repair of a Cresta-0216;

My device looks like this (pictures can be enlarged by clicking):

i'll be posting some update if i have them

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[-] [email protected] 2 points 1 year ago* (last edited 1 year ago)

Replaced the original board with Arduino Nano

After having an idea of how the logic worked, i connected the Arduino (impressive size difference!)

Result

At the moment, it's a fixed text dancing over the screen.

The flatcable has the following pins;

  • +5v --> connected to Arduino nano pin +5v (Not the Vin pin)
  • Gnd --> connected to Arduino nano pin Gnd
  • Clock --> connected to Arduino nano pin D2
  • Data --> connected to Arduino nano pin D3
  • Horizontal line 1enable(top) --> connected to Arduino nano pin D4
  • Horizontal line 2 enable --> connected to Arduino nano pin D5
  • Horizontal line 3 enable --> connected to Arduino nano pin D6
  • Horizontal line 4 enable --> connected to Arduino nano pin D7
  • Horizontal line 5 enable --> connected to Arduino nano pin D8
  • Horizontal line 6 enable --> connected to Arduino nano ping D9
  • Horizontal line 7 enable(bottom) --> connected to Arduino nano pin D10

The nano is said to be protected for connecting both USB and +5v power source simultaneous (the UNO isn't)

Basically, how the program works;

  • it slides in all the bits for a single row via the data and clk pin
  • it enables the appropriate horizontal line and disables it again
  • goes for the next line
  • it uses a char[19*5] array which acts as a bitmap which is rendered to the LED screen.
  • a function renders a text with offset and wiggle to the bitmap. i found the asscii font via this link
[-] [email protected] 1 points 1 year ago* (last edited 1 year ago)

I'm having memory shortage in the Nano, mostly because of the ascii-font table. Also, the cpu power is quite limited. Any extra work immediately affects the scrolling speed. e.g. performing a math.sin() for each column slows down the so much that the display to flicker. Doing a webserver task as well, will not work.

i'm investigating a NodeMCU ESP8266 board, as it also support creating a Wifi Access Point(AP). An AP would allow for configuration by web-browser. But it seems the NodeMCU board doesn't have proper General Purpose I/O-pins. They all seem to be affected at boot.. https://rabbithole.wwwdotorg.org/2017/03/28/esp8266-gpio.html

Here's a picture from that website to remember:

Above: ESP8266 GPIO digital behaviour at boot, when running a simple Arduino application that does nothing except to set all GPIOs to output a low value at boot.

this post was submitted on 05 Aug 2023
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