For many microcontroller projects requiring accurate temperature sensing the sensor of choice is the Maxim DS18B20.  Although this has a specified absolute accuracy of +/- 0.5°C, it has several drawbacks, not least of which is its relatively high cost.  For my prototype sensors I incorporated a TI TMP112, which is an I2C device with a [...]

I finally found the time to make some measurements on the printed antenna used on my sensor board, which I didn’t think was performing very well.  Turns out I was right. For this first part of the test various antenna configurations were tested by mounting them on unpopulated sensor boards connected to an Anritsu Sitemaster [...]

Over the last few weeks I have been helping out the guys over at OpenTRV with an implementation of the FHT protocol for use with HopeRF RFM22B and RFM23B modules.  My as-yet unreleased sensor modules (as seen in another post) make use of an RFM23B, and I have an interest in evaluating the Conrad/ELV FHT8V [...]

I’m going to start by admitting that this isn’t going to be a tirade of abuse against the oddly named 802.15.4-based wireless tech, but rather a request for comments on an open, lightweight alternative, particularly for low-cost sub-GHz applications.  I know what the point of ZigBee is, and the ability to form into self-organising mesh [...]

As part of my project to bring our central heating into the 21st century I have been working on a custom wireless sensor platform.  My key aim here is to develop a low-cost, open solution with security designed in from the start; something that a lot of sub-GHz protocols seem to totally omit.  I’m avoiding [...]