- on Miscellaneous Electronics
- Published in issue 1/2010 on page 72
Indoor / outdoor thermometer + Temperature stabilisation + Keep it warm
Indoor / outdoor thermometer
Here’s an indoor / outdoor thermometer using two DS18S20 detectors with a 2×16 character LCD display. The temperatures are displayed alternately about every two seconds. The first line shows the current temperature (preceded by the indications ‘Tin’ or ‘Tout’) and on the second line are the maximum and minimum temperatures, preceded by ‘M’ for the maximum temperature and ‘m’ for the minimum.
It was necessary to design a temperature controller for a small oven using minimum hardware to keep costs down. The first design attempt feeds the temperature sensor output into a comparator followed by an inverting 4093 NAND gate. This produces a simple on/off control signal to an electronic relay switching a heating element.
Keep it warm
This simple circuit helps temperature dependent ICs or other components to reach their optimal working temperature as quickly as possible, and keep their operating temperature stable. The heater is made of a set of SMD resistors positioned underneath the IC under treatment