British Gas Hive Thermostat no signal issues

I recently replaced my home heating controls with the Hive system from British Gas as my old system had developed a fault with the receiver not switching on the boiler intermittently due to a faulty relay contact. The Hive system worked great for about 3 months until the other day when I noticed it was cold and the heating wasn’t working.

Thinking there was a fault with the boiler I had a look but everything was OK. The Hive receiver was showing the green light indicating that everything was OK. However everything was not OK. The hive thermostat just showed “NO SIGNAL” and no amount of resetting both the thermostat nor receiver would make it work. I decided to move the thermostat next to the boiler and hey presto! It worked. Took it back downstairs and no signal again. What was going on?

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Arduino 6 input DVM 0 to +50V range

This is a project I built for work as an add on to our battery tester which is able to test up to six batteries at once. The battery tester is controlled by a PLC and does not show voltages in real time so we had no idea how long the battery runtime was remaining. A voltmeter that showed the battery voltage under test was required as our tester cuts off the battery at 10.5V for 12V and 21V for 24V lead acid batteries. At first I planned to use a standard panel meter and a six way switch to select the battery under test. This however proved to be quite (in comparison to alternatives) an expensive way of doing this.

Arduino 6 input voltmeter

I decided to make use of a few spare parts I had laying round in the workshop and make a digital voltmeter that could monitor six battery voltages at once on a single LCD. This would obviously have to be microcontroller based so I chose the Arduino over the 8051 due to it’s built in ADC and ease of use. As you can see from the photo the project uses a 20×4 character LCD and also monitors the temperature of the heatsink the load resistors are mounted to. A DS18B20 one wire digital thermometer was used for this and the battery voltage monitoring wires were connected to the Arduino’s ADC ports A0-A5 via a voltage divider.

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