A Long Story...

I've had an Arduino for a year or two, and fooled around with it, and not blogged anything. Bad me.

So here's the blog...

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Replacing Coffee Machine Pump (Dualit Espressivo)

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My 5 year old Dualit Espressivo broke on Saturday - disaster!! I was in the throes of making a coffee when the pump stopped, so no steamed microfoamed milk... Off with the back, check of voltages etc., taking extreme care because 240V + H2O is a Bad Thing. I located what seemed to be the pump, and there were volts on the terminals. Hmm. It’s an Ulka EP5FM according to the label. Google... Many people offering to sell me one, but the guys at ulka-ceme.co.uk aka Scintilla Pumps are the UK distributors. They sell a whole range of this type of pump, and the documentation shows that the crucial points are voltage/power, pressure (15 bar) and duty cycle (2m on/1m off). I can buy one online but I call them... they’re about 15 miles away, and are happy to sell me a replacement. We reckon it’s worth a lunch trip, so bowl over and it’s only £16 direct, vs £19.60 mail order. Done. The expensive part was lunch - £50!! Planning to skip dinner though... New pump fitted - looks like the old...
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Multiple SHT30 sensors on a single I2C bus with Sonoff-Tasmota

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I have a hankering to measure the input and output temperatures of my condensing boiler, in order to determine if it's likely to be actually condensing at any time. I have lots of SHT30 sensors, which attach handily to NodeMCU units. However, running 2 separate rigs, one each for input and output, means that temperature measurements will not be synchronised, which doesn't account for the action of the boiler and its heat output rate of change. It appears that the SHT30 has two I2C addresses (0x44 and 0x45), which are available on the Wemos D1 knock-offs that I have. So I started out by modifying one to use a different bus from the standard one - this is easily done by bridging a link with solder. I then used 2 NodeMCUs running together to check that the newly addressed device is actually detected and works. It does. Pair of NodeMCU/SHT30 setups in action Close-up of SHT30 devices -RH(44) has soldered address link (circled) So, let's see what we can do, eh? I...
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Towards a better doorbell...

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Something we struggle with as a household is the front door bell. We have a wireless pushbutton at the door, with three (3) separate mains or battery-powered devices listening and responding to make sure there's one in earshot. However, the button's range is limited within the house by walls and other things, so it's hard to make sure a) the responders are in range b) they are close enough for us to hear! How about a doorbell that sends a text to the phone? Perfectly possible, surely. Stick an ESP8266 in the closest responder (mains-powered) that looks for the signal to ring the bell on one of its GPIO pins; this has to be possible surely! Have ESP8266 publish an MQTT "front door bell rung" message  Have a Node RED node listen for this and trigger whatever we fancy on its receipt e.g. A text message to one or more phones (handy if we're out, actually) An indicator to a camera  A Klaxon at the back of the house BAR-BAR-BAR ALERT!! Cool. 1 looks ...
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