Cornell University Genetically Engineered Machines



With the temperature sensor and heating circuit placed inside the incubation chamber, the rate of heating when full power (100% PWM) was applied and the rate of cooling when the heating circuit was switched off was graphed in Figure 1. Some initial calibration runs were then performed as we fine tuned our heating algorithm.
Figure 1: Heating and Cooling curves

As the optimal temperature for fungi growth is 27°C, we calculated the difference between the measured temperature and optimal temperature. When the difference is more than 5°C cooler than optimal ie. more than 25°C, maximum heat is applied so as to quickly heat the chamber. As the temperature difference decreases, the duty cycle decreases proportionally until the temperature is at 27°C. Once the temperature increases beyond the optimal, the heating circuit shuts off. temperaturecalibration
Figure 2: Calibration to Optimal Temperature

As seen in Figure 2, From room temperature (24°C), it takes less than 5 minutes for the incubation chamber to reach optimal temperature (27°C) and it remains stable.


A HH10D humidity sensor module was used to measure the relative humidity of the environment. This sensor was connected according to manufacturer instructions such as connecting power, ground, frequency output, SCL, and SDA to the corresponding pins on the sensor board.

To collect data about the humidity, a mistmaker was used to increase the relative humidity of the surrounding area, and the humidity sensor was placed in the vicinity of this mistmaker from the start. This experiment was done by putting the mistmaker in a box, making sure to not allow the mist to escape, and as the mistmaker distributed the water more evenly throughout the box, the relative humidity increased. As the amount of humidity began to increase, the sensor could measure the increase in relative humidity.
Figure 3: Increase in humidity levels using a mistmaker