MICROPROCESSOR-CONTROLLED THERMOSTAT FOR ORGAN BATHS.

Background: Temperature-controlled baths are widely used in medico-biological laboratories and there is a wide offer of these equipments on the market. The price can vary, depending mainly on the thermostat precision. Our aim was to build a high precision thermostat with hysteresis capability at a very low cost. Material and methods: The thermostat was developed using PIC16F84 8-bit microcontroller, produced by Microchip Inc., using an DS8B20 high precision temperature sensor produced by Dallas Semiconductors. The software was developed in C language and the device memory is 82% full. To control the heater, the device uses a 10 A relay, able to handle 2200W maximum. To display the parameters, a 4 digit LED device is used. Results: Our thermostat is compact (7X8 cm) and it has a low power consumption (3W). The resolution is 0.1° C for temperature reading and 1 °C for hysteresis settings. The range of the controller is between -30 and +100°C, depending mainly on the heater capabilities. Conclusions: The device has good precision and the price is very low, so it can be used in a wide range of laboratory temperature control devices (heaters, organ baths, culture incubators). The LED display ensures a good readability and low power consumption. This work was supported by a grant of the Romanian National Authority for Scientific Research and Innovation, CNCS - UEFISCDI, project number PN-II-RU-TE-2014-4-1544. [ABSTRACT FROM AUTHOR]