Temperature controlling is easy with Temper. It uses an improved PID algorithm to decrease overshoots and regulate based on continued inputs.


Add this line to your application's Gemfile:

gem 'temper-control', require: 'temper'

And then execute:

$ bundle

Or install it yourself as:

$ gem install temper-control


To start, create an instance of Temper::PID. The PID algorithm can be configured with custom minimum and maximum values for ease of integration with external control systems (PWM-controlled heating elements, for example). Once created, run Temper::PID#control in your control loop, feeding it sensor data.

Minimum Interval Calculation

The algorithm being used is minimum interval and will not recalibrate until the time interval has passed before recalibrating. This helps mitigate excess compensation and inconsistent adjustment. The update interval is also configurable in Temper with the interval option.

Directional Control

When handling cooling-based temperature control, negative values are a pain for translation. To assist with this, Temper uses a directional control parameter. The two possible states are :direct and :reverse. When using :reverse, negative values are inverted.


Temper's PID is manually tuned with the tune method, which takes a Kp, Ki, and Kd value. By default, Temper will set them to 1.0


require 'temper'

temper = Temper::PID.new(interval: 1000, minimum: 0, maximum: 1000, direction: :direct)
temper.tune(9.0, 25.0, 6.0) # Set Kp, Ki, and Kd
temper.setpoint = 100.0       # Set target temperature

while input = read_sensor()   # Replace read_sensor with your external system
  output = temper.control(input)
  # output is a value betwen minimum and maximum. This can be used for thresholds or
  # PWM-based control


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request