Temperature Curve

All Revisions

Works with all hardware revisions (Rev 1.0 through Rev 3.3).

Purpose

The Temperature Curve module lets you define a custom 5-point temperature-to-speed curve for granular control over fan behavior. Values between points are linearly interpolated, giving you a smooth speed transition across the entire temperature range.

When to Use

Choose Curve when you need more control points than the linear module’s three zones but don’t need PID’s automatic target-chasing behavior. It’s ideal when you know exactly how you want fans to respond at specific temperatures.

For simpler threshold-based control, see Temperature Linear. For automatic temperature targeting, see Temperature PID. The modules overview has a comparison table.

Works with Stall Guard

This module cooperates with Stall Guard via a safety floor mechanism. If a fan stalls, Stall Guard sets a minimum speed that Temperature Curve will respect during recovery. No extra configuration needed — just include both modules.

Configuration

Variable	Default	Description
friendly_name	"Fancontroller"	Device name prefix for all entities
curve_temp1	"20.0"	Temperature point 1 (C)
curve_speed1	"0.0"	Fan speed at point 1 (%)
curve_temp2	"25.0"	Temperature point 2 (C)
curve_speed2	"25.0"	Fan speed at point 2 (%)
curve_temp3	"30.0"	Temperature point 3 (C)
curve_speed3	"50.0"	Fan speed at point 3 (%)
curve_temp4	"40.0"	Temperature point 4 (C)
curve_speed4	"75.0"	Fan speed at point 4 (%)
curve_temp5	"50.0"	Temperature point 5 (C)
curve_speed5	"100.0"	Fan speed at point 5 (%)

How It Works

The five temperature/speed pairs define a piecewise linear curve:

1. Each pair sets a “point” on the curve (e.g., 25 C = 25% speed)
2. Between any two adjacent points, the fan speed is linearly interpolated
3. Below the lowest temperature point, fans run at that point’s speed
4. Above the highest temperature point, fans run at that point’s speed

Auto-sorting: Temperature points are automatically sorted at runtime, so they work even if defined out of order. However, the module validates the curve at boot and logs a warning if points are not monotonically increasing.

Home Assistant Entities

Number Entities

Entity	Range	Step	Unit	Default	Description
Curve Temperature 1	0 — 60	0.5	C	20.0	Temperature point 1
Curve Speed 1	0 — 100	1	%	0	Fan speed at point 1
Curve Temperature 2	0 — 60	0.5	C	25.0	Temperature point 2
Curve Speed 2	0 — 100	1	%	25	Fan speed at point 2
Curve Temperature 3	0 — 60	0.5	C	30.0	Temperature point 3
Curve Speed 3	0 — 100	1	%	50	Fan speed at point 3
Curve Temperature 4	0 — 60	0.5	C	40.0	Temperature point 4
Curve Speed 4	0 — 100	1	%	75	Fan speed at point 4
Curve Temperature 5	0 — 60	0.5	C	50.0	Temperature point 5
Curve Speed 5	0 — 100	1	%	100	Fan speed at point 5

Sensor Entities

Entity	Unit	Description
Curve Output	%	Current interpolated fan speed (updated every 10s)

Switch Entities

Entity	Default	Description
Auto Control Fan 1	ON	Enable curve control for fan 1
Auto Control Fan 2	ON	Enable curve control for fan 2
Auto Control Fan 3	ON	Enable curve control for fan 3
Auto Control Fan 4	ON	Enable curve control for fan 4

Binary Sensor

Entity	Category	Description
Curve Configuration Warning	Diagnostic	ON if temperature points are not monotonically increasing

YAML Examples

Basic Usage (Default Balanced Curve)

packages:
  temperature_curve:
    url: https://github.com/zeroflow/wifi-fancontroller
    ref: main
    files:
      - path: modules/temperature_curve.yaml
        vars:
          friendly_name: "My Fan Controller"

Silent Profile

Prioritizes low noise. Fans stay off until 25 C and ramp slowly, reaching only 80% at 55 C. Best for quiet home office environments where some temperature rise is acceptable.

packages:
  temperature_curve:
    url: https://github.com/zeroflow/wifi-fancontroller
    ref: main
    files:
      - path: modules/temperature_curve.yaml
        vars:
          friendly_name: "Silent Cooler"
          curve_temp1: "20.0"
          curve_speed1: "0.0"
          curve_temp2: "25.0"
          curve_speed2: "20.0"
          curve_temp3: "35.0"
          curve_speed3: "40.0"
          curve_temp4: "45.0"
          curve_speed4: "60.0"
          curve_temp5: "55.0"
          curve_speed5: "80.0"

Balanced Profile

Good all-around curve that balances noise and cooling. This is the default configuration.

packages:
  temperature_curve:
    url: https://github.com/zeroflow/wifi-fancontroller
    ref: main
    files:
      - path: modules/temperature_curve.yaml
        vars:
          friendly_name: "Balanced Cooler"
          curve_temp1: "20.0"
          curve_speed1: "0.0"
          curve_temp2: "25.0"
          curve_speed2: "25.0"
          curve_temp3: "30.0"
          curve_speed3: "50.0"
          curve_temp4: "40.0"
          curve_speed4: "75.0"
          curve_temp5: "50.0"
          curve_speed5: "100.0"

Aggressive Profile

Reacts quickly to temperature increases with steep ramp. Reaches full speed at 40 C. Best for high-performance setups where cooling takes priority over noise.

packages:
  temperature_curve:
    url: https://github.com/zeroflow/wifi-fancontroller
    ref: main
    files:
      - path: modules/temperature_curve.yaml
        vars:
          friendly_name: "Aggressive Cooler"
          curve_temp1: "20.0"
          curve_speed1: "0.0"
          curve_temp2: "22.0"
          curve_speed2: "30.0"
          curve_temp3: "28.0"
          curve_speed3: "60.0"
          curve_temp4: "35.0"
          curve_speed4: "85.0"
          curve_temp5: "40.0"
          curve_speed5: "100.0"

Server Profile

Always-on baseline cooling with rapid ramp. Fans never fully stop (20% minimum at 15 C), reaching full speed at just 35 C. Designed for server racks and network closets.

packages:
  temperature_curve:
    url: https://github.com/zeroflow/wifi-fancontroller
    ref: main
    files:
      - path: modules/temperature_curve.yaml
        vars:
          friendly_name: "Server Rack"
          curve_temp1: "15.0"
          curve_speed1: "20.0"
          curve_temp2: "20.0"
          curve_speed2: "30.0"
          curve_temp3: "25.0"
          curve_speed3: "50.0"
          curve_temp4: "30.0"
          curve_speed4: "75.0"
          curve_temp5: "35.0"
          curve_speed5: "100.0"

Tuning Tips

Use the HA Number Entities

All 10 curve parameters can be adjusted live from Home Assistant without reflashing. Experiment with different values and watch the Curve Output sensor to see the effect in real time.

• Watch the Configuration Warning sensor — if it shows ON in Home Assistant, your temperature points are not in ascending order. The module still works (points are auto-sorted at runtime), but it’s best practice to define them in order for clarity.
• Define temperatures in ascending order — while auto-sorting handles out-of-order points, having them in order makes your configuration easier to read and debug.
• Start with the Balanced preset — the default curve works well for most scenarios. Adjust individual points based on your environment.
• Consider your fans’ minimum speed — if your fans need at least 20% PWM to spin reliably, make sure your lowest non-zero speed point is at or above that threshold.
• Use the Curve Output sensor for debugging — it updates every 10 seconds and shows the current interpolated fan speed, making it easy to verify your curve behaves as expected at different temperatures.