This controller directly controls Hanover Displays Ltd. dot-boards CMOS logic hardware directly through the parallel 14-pin ribbon cable, without the Hanover 7070 or 7080 processor board.
This controller's design is based on Damien Walsh's work on Hanover flip-dot signs, with only layout changes targeting PCB fabrication and assembly services.
The following considerations went into the PCB schematic and layout:
- SMT components used where possible
- All components are only on the top side of the PCB
- The ESP32-PICO-D4 SIP is used instead of a separate ESP32 module
- PCB size minimized to increase savings with panelization
- All board enable lines are connected to support up to 4 parallel dot-boards
- Generous use of ground stitching vias
I strongly suggest removing the following items from the PCBA BoM, as they are generic 2.54mm through-hole parts and can be easily sourced at a local dealer:
- J2: CONN HEADER R/A 14POS 2.54MM
- J3: DIP Black Male Header VERT
J2 is specified as a 2x7 pin 2.54mm pitch shrouded header for IDC cables, so a matching 2x7 pin 2.54mm pitch IDC connector must be retrofitted on the original Hanover dot-board ribbon cable.
The original Hanover cable is a Lumberg Micromodul series MICA 14 connector which mates to a corresponding MICS 14 header. As the Lumberg Micromodul parts are much harder to source (with the bottom line being that they cost more) and requires a custom footprint on the PCB, a jellybean part solution was preferred.
The BOM CSV provided uses Seeed Studio OPL SKUs for jellybean parts as I have a personal preference for Seeed Studio's Fusion PCBA service. If using other PCBA services, please substitute the Seeed OPL SKUs accordingly.
Reference ESP32 Arduino framework firmware source is available at ndoo/esp32-hanover-flipdot-firmware
- Enable Display 1 - GPIO 15
- Enable Display 2 - GPIO 13
- Enable Display 3 - GPIO 12
- Enable Display 4 - GPIO 14
- Column Advance - GPIO 27
- Reset - GPIO 26
- Set/Unset - GPIO 25
- Row Advance - GPIO 33
- Coil Pulse - GPIO 2
- LED 1 - GPIO 23
- LED 2 - GPIO 19
- LED 3 - GPIO 22