An Adafruit Max31855 thermocouple amplifier and a K-type thermocoupler as the temperature sensor.A styrofoam box as the insulation material.A 75W incandescent light bulb as the heating element.It’s good to learn from your mistakes, but not with the mains power!!! If you are a newbie for working with mains power (~110V/~220V) it might be a good idea to consult someone who has good experience with it to help you. By controlling the T1 we can control the output power of the load. Once we detect this point we can wait T1 amount of time before we switch ON the AC signal to go through the load. This happens at the beginning (and the end) of each half cycle and the zero crossing detector outputs a square pulse at each of these points. As the name suggests, zero-crossing point is where the AC signal crosses the 0V level or the point it changes its direction. For that we use a Zero-Crossing detector. Simply, the power control mechanism should be synchronised with the input AC signal. Therefore we need to know the current position of the AC cycle exactly before allowing it to go through the load in order to achieve desired output power. Unlike DC supplies, where the voltage is constant at any given time, the voltage of an AC supply follows a sine waveform. This is somewhat similar to Pulse-Width-Modulation(PWM) in DC. In AC phase control, we control the input power supplied to the load (in our case the tungsten bulb) by allowing only a part of each half cycle of the AC signal to go through it. This step has some technical details before we get into the practical steps of assembling the incubator. In this step, we discuss how to control the AC supply using AC phase control mechanism. This project is by Piyum Fernando, Matthew Pandelakis, and Stacey Kuznetsov at the Social And Digital Systems (SANDS) Group at Arizona State University. Hence, we can control the temperature inside the incubator by controlling the AC input supplied to the bulb. The amount of heat emitted by the tungsten bulb is proportional to the power applied to the bulb. Once the desired temperature is reached, the bulb should emit the same amount of heat as what’s lost. In other words, to increase the temperature, the bulb needs to emit more heat than the heat loss through the walls. The change in temperature inside the incubator is proportional to the amount of heat emitted by the tungsten bulb minus the heat loss through the walls of the incubator. On the most basic level, we are using a temperature sensor and a light bulb as our heating element. The goal of the incubator is to keep a constant temperature inside. In this instructable, we describe how to build a low cost (under 70$), yet accurate ( +/- 0.25C) DIY incubator using simple materials and some basic electronics components.Ī not-too-technical overview of how our incubator works. Given the higher price range of the commercially available incubators (upwards of several thousand dollars), non-professional biology enthusiasts might not afford to add an incubator to their stock of DIYbio tools. Our project contributes to the growing number of open source biology tools by developing a low-cost, yet relatively precise and easy-to-use incubator.Īn incubator is an essential tool for a number of biological experiments and is often used in bacterial cell culture experiments. These exciting developments pave the way for crowdsourcing biology research amongst students, hobbyists, and non-experts. Over the past few years, platforms such as OpenPCR and Pearl Biotech transilluminator have been designed to support biology work in schools and maker spaces for a fraction of the cost of professional lab equipment. DIYbio, (Do It Yourself) biology is a growing movement that aims to make biology accessible outside of professional contexts.
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