83 lines
3.7 KiB
Markdown
83 lines
3.7 KiB
Markdown
# piNail Hardware (Prototype v2)
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This file captures confirmed hardware details for the cigar-box prototype.
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Unknowns are marked `TBD` instead of guessed.
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## Prototype Summary
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- Enclosure: cigar box with integrated monitor in lid.
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- Input power: IEC C14-style AC inlet ("computer PSU" style).
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- Runtime controller: Raspberry Pi.
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- Heating channels: 2 coil channels (channel 2 wired but not yet validated in operation).
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## High-Level Power Architecture
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### AC input path
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1. AC inlet -> WiFi power switch.
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2. From WiFi switch output -> master mains switch for system.
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3. Master switch output branches:
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- Branch A: to main DC switching PSU (powers Pi/control electronics).
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- Branch B: to per-channel heater paths.
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### Control electronics power (DC)
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- Main DC PSU output provides control-side power for:
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- Raspberry Pi
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- Two thermocouple interface chips
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- Two SSR control sides
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- Nominal rail appears to be `5V` (TBD: confirm exact PSU output voltage/current).
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### Heater power path (per channel)
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- After master switch, AC route per channel is:
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- fuse -> manual front-panel cutoff switch -> SSR load side -> coil connector power line
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- The opposite AC pole is routed from WiFi switch output directly to coil connector corresponding pole.
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- Ground/earth conductor is routed to coil connector grounds.
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## Channel/Signal Topology
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- Each channel has:
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- Thermocouple input (via MAX6675-type board)
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- SSR-driven AC heater output
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- Manual front panel power switch in series with heater path
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- Raspberry Pi drives each relay channel independently.
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- Thermocouple boards are connected to Pi GPIO.
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## GPIO Wiring (User-Confirmed)
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- Thermocouple channel 1 GPIO lines: `GPIO 5`, `GPIO 8`, `GPIO 7`.
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- Thermocouple channel 2 GPIO lines: `GPIO 11`, `GPIO 12`, `GPIO 13`.
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- Channel 2 thermocouple mapping corresponds line-for-line to channel 1 mapping (`5/8/7` -> `11/12/13`).
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- Relay control (channel 2): `GPIO 9`.
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- `TBD`: confirm relay control GPIO for channel 1 in this dual-channel prototype wiring doc.
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- Note: these dual-channel GPIO assignments differ from the current single-channel `piNail2/config.json` runtime pins.
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## Monitor Subsystem
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- Separate 12V power supply for the built-in monitor.
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- Short HDMI from Pi -> monitor.
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- Monitor considered optional for future versions.
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## Grounding Notes
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- Enclosure is non-metal (cigar box), so chassis bonding is not the main factor here.
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- Coil grounds are connected.
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- DC PSU ground is connected on the input-side ground scheme.
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- `TBD`: provide explicit earth/neutral/hot naming by region and verify continuity paths.
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## Protection and Switching (Current Understanding)
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- SSRs used for heater switching (`TBD`: exact model/rating).
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- Fuses appear to be 1A glass tube, one per channel (`TBD`: verify rating + slow/fast blow type).
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- Per-channel front switches are manual toggles.
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- WiFi switch has onboard button and can keep networked power state independent of channel switches.
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## Operational Behavior (as built)
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- You can power down Pi + nail supply via master mains switch while keeping WiFi switch infrastructure behavior available.
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- You can cut each coil independently with front-panel switches without shutting down software.
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- Channel 2 is wired but not yet fully tested under load.
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## Legacy/Prototype Context
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- Prototype v1: external Pi setup (pinout/relay/thermocouple cable to Pi), no built-in monitor.
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- Prototype v2: integrated Pi + wiring + optional integrated monitor.
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## Required TBDs Before Final Electrical Spec
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1. Coil connector pinout (both channels, exact pin numbering/function).
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2. Main DC PSU make/model and output spec (V/A).
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3. SSR model and AC load ratings.
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4. Fuse exact spec (amp, voltage, blow type, holder type).
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5. Exact line/neutral/earth routing confirmation diagram.
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6. Channel 2 validation checklist/results.
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