Introduction/Abstract
The 2021 SUNY Oneonta iGEM project focused on creating a field deployable detection system for favorable traits in cattle. Our detection system required a simple portable heating hardware that can be easily used in the field. Scientists often need to control the temperature of the samples in their experiments. They can do this in a variety of ways, including putting their sample on ice, in an oven, in a heated water bath, or in a device called a heat block. A heat block is a block of metal with holes drilled in it to fit samples. The temperature is regulated by controlling the amount of electrical power that flows through the heat block.
In this study, we designed heat block prototypes using easily accessible and low-cost parts.
The experimental procedure was designed to:
- Test the heat block’s ability to reach a specific temperature quickly and safely
- Demonstrate that the heat block can remain at a constant temperature during an experiment
- Affirm that the heat block can cool down quickly and safely
Experiment Procedure Objectives:
Target Temperature Procedure
This first step will test the duration of time the heat block will take to reach a predetermined temperature. The target temperature for this step is 37°C. The temperature is to be recorded every 30 seconds for 360 seconds.
Consistency Procedure
The second step will test the accuracy of the heat block to maintain a set temperature for the allocated time. The temperature of the heat block is to be recorded every 30 seconds for 360 seconds.
Cool Down Temperature Procedure
The third step will test the effectiveness of the heat block’s ability to cool down from its target temperature. The temperature was recorded every 30 seconds for 360 seconds or until the heat block reaches your recorded room temperature.
Safety Materials:
- Heat resistant gloves
- Googles
- Lab Coat or long clothes
Software Development
Hardware Integration
Utilizing a Raspberry Pi 3B as a Programmable Logic Controller as well as I/O sensors, we were able to successfully utilize automation algorithms to detect and regulate temperature on the heat block.
Target Temperature Detection and Regulation
To control the Peltier Chip, we utilized Python Scripting to control a low power current which functioned as the base of a transistor circuit. When the attached temperature sensor was reading below the desired temperature, an electrical current was sent from the Raspberry Pi to toggle the Peltier Chip on. Once the temperature sensor indicated that the Heat Block was at or above the desired temperature, the current was terminated which toggled the Peltier Chip off.
Visual indicators in the form of Green and Red LEDs were utilized to inform the user that the Heat Block was either at the desired temperature (Green) or it was adjusting to the new parameters (Red).
Further Development In the coming months, we plan to further develop this device by adding fans to assist in temperature regulation, specifically in more rapidly reducing the temperature of the heat block in the event that the Peltier Chip overheats.
Figure 1: Schematic Diagram of Raspberry Pi Implementation Within a Transistor Circut. LED Diodes were used for testing and debugging purposes and later switched to the Peltier Chip for heat regulation.