Talos Hardware Daemon

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Talos is a Rust-based hardware daemon for reliable, low-latency I2C communication with Sequent Microsystems HATs on Raspberry Pi. It is the sole owner of the I2C bus — all hardware reads and writes flow through its HTTP API on port 6100.

Part of the NexusEdge industrial control platform by AutomataNexus.

Features

• Polls all enabled Sequent Microsystems boards every 1 second
• Caches all sensor readings in memory (sub-millisecond API response)
• REST API for reading cached values and writing outputs
• Reports raw hardware metrics to local Aegis-DB every 5 seconds
• I2C bus retry and error recovery
• GPIO pin support for direct-relay boards (e.g. Waveshare)
• Static musl binaries — no GLIBC dependency, runs on any ARM Linux

Supported Boards

Board	I2C Base	Channels	Use Case
MegaBAS	0x48	8 AI, 4 AO, 4 triacs, 8 dry contacts, 8× 1K/10K resistance	General HVAC I/O
MegaIND	0x50	4 voltage in, 4 current in, 4 voltage out, 4 current out	Industrial I/O
UnivIn16	0x40	16 universal inputs (voltage, 1K, 10K)	Large input count
UOut16	0x60	16 analog outputs (0–10V)	Large output count
RelInd16	0x58	16 relays	Relay banks
RelInd8	0x38	8 relays	Relay banks

Each board type supports stacking up to 8 units (address = base + stack, 0–7).

Architecture

                ┌─────────────────────────────────┐
                │           main.rs                │
                │  Loads config, spawns threads,   │
                │  starts HTTP server              │
                └────┬──────┬──────┬──────┬───────┘
                     │      │      │      │
        ┌────────────▼┐ ┌──▼────┐ ┌▼─────▼──────┐
        │ poller.rs    │ │writer │ │ server.rs    │
        │ (std thread) │ │.rs    │ │ (tokio)      │
        │ Reads I2C    │ │Writes │ │ Axum HTTP    │
        │ every 1s     │ │I2C    │ │ on :6100     │
        │ Updates cache│ │from Q │ │              │
        └──────┬───────┘ └───┬───┘ └──────┬──────┘
               │             │             │
        ┌──────▼─────────────▼─────────────▼──────┐
        │              cache.rs                     │
        │  SharedCache (parking_lot::RwLock)        │
        │  HashMap<stack, BoardData> per board type │
        └──────────────────────────────────────────┘
               │
        ┌──────▼──────┐
        │ aegisdb.rs   │
        │ (tokio task) │
        │ Reports to   │
        │ local :9090  │
        └─────────────┘

Thread model:

• Poller (std thread) — owns one I2C bus fd, reads all boards, updates shared cache
• Writer (std thread) — owns separate I2C bus fd, processes write commands from crossbeam channel
• HTTP server (tokio) — serves API requests, reads cache, sends write commands to writer queue
• Aegis-DB reporter (tokio task) — reads cache every 5s, batch-inserts to local Aegis-DB

Installation

From Release Binary

Download the latest binary from Releases:

# Raspberry Pi 3/4 (32-bit) — ARMv7
wget https://github.com/AutomataNexus/Talos/releases/latest/download/talos-hwdaemon-armv7
chmod +x talos-hwdaemon-armv7
sudo mv talos-hwdaemon-armv7 /usr/local/bin/talos-hwdaemon

# Raspberry Pi 4/5 (64-bit) — AArch64
wget https://github.com/AutomataNexus/Talos/releases/latest/download/talos-hwdaemon-aarch64
chmod +x talos-hwdaemon-aarch64
sudo mv talos-hwdaemon-aarch64 /usr/local/bin/talos-hwdaemon

Configuration

Copy the example config to /etc/nexusedge/ or the daemon's working directory:

sudo mkdir -p /etc/nexusedge
sudo cp hardware-daemon.toml /etc/nexusedge/hardware-daemon.toml

Edit the config to enable your boards and set stack addresses:

[server]
host = "127.0.0.1"
port = 6100

[polling]
interval_ms = 1000

[i2c]
bus = 1
retry_count = 3
retry_delay_ms = 10

[boards.megabas]
enabled = true
stacks = [0]

[boards.megaind]
enabled = false
stacks = []

Run with PM2

pm2 start talos-hwdaemon --name talos-daemon
pm2 save --force

API Quick Reference

All endpoints serve on http://127.0.0.1:6100 (localhost only).

Read Cached Data

# Full cache (all boards, all channels)
curl -s http://localhost:6100/cache

# Health + board connectivity
curl -s http://localhost:6100/health

# MegaBAS channels
curl -s http://localhost:6100/megabas/analog_inputs?stack=0
curl -s http://localhost:6100/megabas/resistance_10k?stack=0
curl -s http://localhost:6100/megabas/contacts?stack=0
curl -s http://localhost:6100/megabas/triacs?stack=0

Write Outputs

# Set triac (channel 1-4)
curl -s -X POST http://localhost:6100/megabas/triac \
  -H "Content-Type: application/json" \
  -d '{"channel": 1, "state": true}'

# Set analog output (channel 1-4, 0-10V)
curl -s -X POST http://localhost:6100/megabas/analog_output \
  -H "Content-Type: application/json" \
  -d '{"channel": 2, "value": 5.0}'

HVAC Signal Conventions

Heating Valve (Normally Open)

Voltage	Position	Heat
0.00V	100% OPEN	Maximum heat
5.00V	50% OPEN	Half heat
10.00V	0% (CLOSED)	No heat

Inverted: Lower voltage = more heat. Formula: voltage = ((100 - heat%) / 100) × 10

Cooling Valve (Normally Closed)

Voltage	Position	Cooling
0.00V	0% (CLOSED)	No cooling
5.00V	50% OPEN	Half cooling
10.00V	100% OPEN	Maximum cooling

Formula: voltage = (cool% / 100) × 10

NTC Thermistor Conversion

The daemon returns raw resistance (ohms). Convert to temperature using Steinhart-Hart:

// 10K NTC Type 2 (Beta = 3950)
const T0 = 298.15, R0 = 10000, B = 3950;
const tempK = 1 / (1/T0 + (1/B) * Math.log(ohms / R0));
const tempF = (tempK - 273.15) * 9/5 + 32;

Resistance	Temperature
30K Ω	~33°F
10K Ω	~77°F (25°C)
5K Ω	~110°F

Examples

See the examples/ directory for a complete working integration:

• coordinator.js — Manages executor lifecycle, health monitoring, graceful shutdown
• executor.js — Reads sensors from Talos API, runs control logic, writes outputs
• logic/equipment/temperature_control.js — Pure control logic for AHU heating/cooling with rate-limited valve ramping

Troubleshooting

GLIBC Errors

If you see GLIBC_2.32 not found, the binary was built with the wrong target. The release binaries use musleabihf/musl (static linking) and have no GLIBC dependency.

I2C Bus Errors

i2cdetect -y 1    # Should show devices at 0x48+ range

Cache Returns Empty

Verify board DIP switch settings match stacks = [...] in your config.

CLI vs Daemon Values

The SM megabas CLI reads the same registers. Note: CLI r10krd returns kΩ, daemon returns Ω.

megabas 0 adcrd 1     # Compare with /megabas/analog_inputs
megabas 0 r10krd 1    # kΩ → multiply by 1000 for daemon Ω

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