Another week, more parts have arrived for the coffee machine!
To save messing around with soldering and cutting more weird little cables I got myself an eBay knockoff of a RaspberryPi Prototyping Board, which exposes most of the pins I need as screw terminals. Once I get to the more permanent stage I can solder things to the included field.
Sadly, mine is blue – purple didn’t seem to be available.
I don’t remember it, but I seem to have purchased the cheapest 2-wire PT100 sensor money could buy, which came with some terribly flimsy wires. I foresee buying another one in short order, once I’ve broken^wplayed with this one a bit.
I quickly updated the code to use the BCM pins – because that’s how the breakout is labelled – and have tested the connectors with my existing switches. All works so far, next up is to wire the power relay and then temperature sensing part in
I bought a new vacuum cleaner recently – the Miele Complete C3 Cat&Dog. A great unit, with a charcoal filter to save me from puppy smells when vacuuming. It also comes with a “Large Turbobrush”, model STB 205-3 which is quite handy for picking up fur. Today I thoughtlessly sucked up the control cord and half the runs-along-the-bottom cord for my vertical blinds (the dogs trashed them months ago).
I’m fairly sure I could respond to 80% of my incident reports with a summarised version of this, and it’s what I waste most of my time on.
The main problem with most people’s troubleshooting is that they don’t start by actually clarifying what’s wrong. Who, What, Where and When generally gives you a lot of information on how to find the Why.
Well that’s a pity. I had ordered a MAX31855 SPI thermocouple interface to capture temperatures on the coffee machine, and after waiting a month the sender’s just given me a refund because it didn’t get delivered.
Back to the drawing board – on a high note this means I might be able to get a MAX31865, which handles four wire PT100(0) sensors, which I have been told are much more reliable.
I’ve had a Rancilio Silvia for a bit over a year now, and it’s been great to make coffee while also saving money and reducing the amount of plastic I was dumping into the bin. One of the popular modifications to them is to install a PID controller to make the heater control more even, and because I’m always up for a challenge I wanted to make my own.
That, and I leave it on often enough that I’m grumpy with myself, as repeated most eloquently by a friend:
Quote of the month: “keep leaving the coffee machine on, figured I could build a timer, turns out I can build a coffee machine with an API and finer temperature control”
That’s awesome. You know who you are.
So the plan is to combine a Raspberry PI, a few Solid State Relays, a temperature sensor, some buttons and some wire to upgrade the interface of Miss Silvia
So far I’ve got a simple control loop working, and it’ll accept input from the two buttons I have configured. It’ll turn “main power” on and off , has VERY simple (and untested) temperature control implemented, and it’ll turn itself off automatically after a set amount of time.
I’m still waiting on the temperature sensor and am pondering where all the parts will fit into the machine so that it’ll last a long time and not die of heat/vibrations/water.