>From a software point of view the Arduino should be able to generate the signals. It is possible that a SPI interface will do a lot of the serial conversion. In terms of a library, once the serial format is known and if (big if) a SPI port can be used, there is probably some library code that could be used as a starting point. I'm sure someone can give a lot better information. There are a couple of things that I am not sure about based on your photos...
- You indicate that the LED displays are 12V. My guess is that the linear regulator with an adjustment resistor for brightness actually drops the voltage (13.6V) to the display The 4.6V is probably the logic Vcc. - One thing I didn't see were current limit resistors. I wonder if they are built into the display? - I am also guessing that the displays are not multiplexed just based on the fact that if they were multiplexed, the sequencing would probably need to be handled by the missing "host" since I don't see anything on the board to handle that. Also the fact that the 00.00 comes up and is not extremely bright makes me think that current/brightness control is built into the display and the segments/digits are not multiplexed. I would be willing to take a look at a board and attempt a hardware reverse engineer to generate a schematic for you. I could also take a stab at generating a document on the driving of the unit. -Bill- On Saturday, January 2, 2021 at 7:40:33 AM UTC-8 Jeffry P wrote: > Will an Arduino work? Is there alibrary that will produce these signals? > > On Thursday, December 31, 2020 at 4:19:22 PM UTC-6 Bill Stanley wrote: > >> Correct, these are a differential receiver to receive the serial (BCD) >> information, 2x8 shift registers to convert to parallel BCD and 4 BCD to >> seven segment LED drivers. >> >> With a bit of sleuthing, the schematic can be reverse engineered, reverse >> engineer the serial format and build or use a COTS CPU like Pi to display >> anything you wish. >> The power supply connector also probably has the serial data (look for >> wires going to the AM26LS32). Somewhere there will be a connection to >> inject that serial stream. >> >> >> -Bill- >> >> >> On Thursday, December 31, 2020 at 1:30:17 PM UTC-8 bani wrote: >> >>> These are not standalone clock displays. They are driven by an external >>> controller over serial. If the controller is not integrated into the >>> PSU, >>> then you are missing the external controller module. >>> >>> Personally I would just design a completely new clock using the LEDs. >>> >>> -Dan >>> >>> On Thu, 31 Dec 2020, Jeffry P wrote: >>> >>> > I purchased a clock display system from a USPS auction about 20 years >>> ago >>> > and recently rediscovered it in my storeroom. There are 20 displays >>> and a >>> > power supply. The displays were housed in a metal enclosure that has a >>> > window cutout for the LEDs. The window had a piece of red colored film >>> and >>> > the LEDs were behind. When I plug the power supply in it will light >>> all 0's >>> > and a decimal point (as seen in photos), but will not start keeping >>> time. >>> > I'm willing to send one of these boards( at my expense) to someone who >>> can >>> > help me get the thing keeping time again. I've attached a few photos >>> with >>> > descriptions of chips that are on the board and voltages measured at >>> the >>> > power supply connector. >>> > >>> > Thank you, Jeffry >>> > >>> > >>> > -- >>> > You received this message because you are subscribed to the Google >>> Groups "neonixie-l" group. >>> > To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> > To view this discussion on the web, visit >>> https://groups.google.com/d/msgid/neonixie-l/85636c40-6036-40b9-9426-24310206c979n%40googlegroups.com. >>> >>> >>> > >>> >> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/0073d96c-8ddf-45df-8982-6354d5a49715n%40googlegroups.com.
