Appearance
Smart Hex hardware
Controller and interfaces
The prototype uses a CH32V003F4P6 development board, rather than the bare chip, to simplify early assembly. The supplier lists 16KB flash and 2KB SRAM; firmware and display buffering need to fit that budget. Pin assignment TBD.
| Interface | Intended allocation | Detail still needed |
|---|---|---|
| Road sensing | 3 analog inputs | ADC-capable pins and placement |
| Building sensing | 3 analog inputs | ADC-capable pins and ownership |
| Land sensing | 1 analog input | ADC-capable pin |
| Robber sensing | 1 digital input | Pull-up and contact wiring |
| Main I²C | SDA, SCL | Pin conflicts and bus voltage |
| Local OLED | Separate SDA, SCL | Possible software I²C pins |
| Chain | CHAIN_IN, CHAIN_OUT | GPIOs and startup levels |
| Programming/debug | Normal CH32 interface | Accessible pins and connector |
The availability of seven usable external ADC inputs must be verified alongside peripheral pin multiplexing and the development board's routing. Total GPIO count alone is not enough. The current no-MUX concept is a requirement to evaluate, not a completed pin map.
OLED
The purchasing reference is a 0.96-inch white I²C OLED. The intended class is 128×64 monochrome, from the SSD1306/SSD1315-compatible family, with an approximately 27×27mm PCB envelope. Verify the actual controller, pin order, supply requirements, and dimensions on the supplied module.
Allow mounting and enclosure clearance for manufacturer variation rather than coupling the design to one supplier's PCB. The final window, mounting holes, and connector clearance are TBD.
Repeated OLED addresses make a single global display bus unsuitable without extra addressing hardware. Each hex should instead control its own OLED on a separate local bus, potentially bit-banged I²C. The CH32 is the endpoint on the shared main bus.
Power and parts
The proposed distribution rail is 5V. That does not establish the correct voltage for every logic pin or ADC input. Each hex needs one controller, one OLED, seven 10kΩ reference resistors, approximately one 10µF smoothing capacitor, and contacts/connectors TBD. See power, BOM, and wiring.