PID Espresso Coffee Machine Mod

PID Coffee

After playing around with an old G3 Ferrari espresso machine, I find that my barista skills are rather lacking. However it becomes difficult to improve them when the espresso machine has such a wide temperature range. Most machines have a simple thermostat that switches the boiler on at one temperature and off at another. This could be over 20 degrees when coffee purists say the best temperature is 92 – 94 degrees C! Continue reading

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Simple Home Automation Web Interface [Part 3]

home_auto

To continue on from my previous posts about the cheap wireless AC outlets, here is some code for a simple web interface that will let you turn on and off the outlets via buttons on a web page. Continue reading

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Home Automation [Part 2] – Scheduling with CRON

# m h dom mon dow command
# * * * * *  command to execute
# ┬ ┬ ┬ ┬ ┬
# │ │ │ │ │
# │ │ │ │ │
# │ │ │ │ └───── day of week (0 - 7) (0 to 6 are Sunday to Saturday)
# │ │ │ └────────── month (1 - 12)
# │ │ └─────────────── day of month (1 - 31)
# │ └──────────────────── hour (0 - 23)
# └───────────────────────── min (0 - 59)

Following on from my last post about the start of a Cheap, Easy Raspberry Pi Home Automation System this post shows how you can schedule outlets to turn off and on at particular times. This is achieved very easily on the Raspberry Pi using the cron program. I suggest reading this introduction to cron on the raspberrypi.org website. Continue reading

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Cheap, Easy Raspberry Pi Home Automation (for Australia) [Part 1]

watssclever2

In my hacking adventures I came across these awesome, super-cheap wirelessly controlled mains power outlets from Jaycar Electroncis in Australia. [UPDATE: This can also be used, but you need to get a 433Mhz transmitter separately]. They are on clearance, which means they are $5 per outlet, so you better read on and get some before they disappear. Don’t be fooled by the fact they are supposedly IR controlled, in truth they aren’t! The IR receiver unit that comes with the kit contains a ubiquitous 433Mhz wireless radio module. Once you know the wireless protocol, it’s straightforward to send commands from a transmitter attached to anything… Continue reading

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DIY Marine Anemometer System

Finally I had time to complete the wind vane system on my sail boat. As I’ve mentioned in previous projects I am using a Peet Bros marine grade anemometer at the top of the mast. I managed to mount the new anemometer in the old existing ‘Signet’ brand frame, which turned out to be an excellent fit after cutting it down slightly. Continue reading

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Reanimating a B&G Network Wind Instrument

$_12

In one of my previous projects I built a masthead wind sensor using an Arduino to process the signals and output a NMEA string. Next I wanted to make an instrument on the boat to display the information. I found a cheap non-working B&G Network Wind display on eBay which fit the bill and set about taking it apart. The display is analogue with a motor and hall sensor to move the wind angle arm. I found that the arm was on too tight and was rubbing on the backing, making it hard for the motor to drive it. After fixing this, I also changed the coin cell battery in the unit which was dead flat. Next I investigated how to simulate the inputs! Continue reading

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Engraving Circuit Boards

pcb1

It’s taken a while, but I finally have my JGRO CNC machine built and running. I spent a bit of time investigating a lot of ground noise on my stepper drivers. I’m using three Gecko G251 stepper drivers for the 3 axes of the machine. Turns out their step and direction inputs are not isolated, so with 3 drivers sharing the same logic ground, decent currents can flow between them. The fix involves adding a 100 ohm resistor in series with each logic ground connection, which reduces the unwanted ground currents. In hindsight, it would have been better to use drivers with isolated inputs, or a specifically designed 3-axis driver board. Continue reading

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