Coffee monitor

[nbw]

Our gorgeous coffee machine has a 3l water tank, but no easy way apart from sticking your head in it, to check the water level. Also, it has a single green neon that is supposed to indicate when the water temp is ok to make coffee. However, it has a wide range of about 30 degrees below and up to the right temp! SO!!!

I made a coffee monitor.

It uses a SRF005 US module to detect water level, and display it on a 16x2 blue LCD, with custom characters so you get a bargraph and % status. It uses a DS18B20 to accurately to show boiler temp. It has two buttons - one to increment cup count - a count of how many cups I've made since we bought it. The other is an espresso shot time - to let you know how many seconds the extraction has been running. There's a trimpot on the top of the case to adjust this from 25s to 1 min for the triple shot. I soldered a green LED into the centre of the trimpot to illuminate it! (I thought it was cool). It does other whizzy things too. Beeps when the water level is getting low. Or when no button has been pushed for 20 mins - means the machine is just sucking power (1.8kW). Or if the boiler is too hot. And plays tunes when 1000, 1500, or 2000 cups have been made

 

[nbw]

2nd lot of pix....

 

[nbw]

3rd lot....

 

[kevrus]

I like the idea of the ultrasonics detecting the water level, gives me an idea for rainwater butt level indication for a little project i'm considering...nice job.

 

[nbw]

Thanks! It's pretty accurate and has a good range. When the coffee water tank is full it's about 6cm away from the sensor, when empty about 22cm. So the Picaxe handles all of the maths in between. The real grunt work is done in the SRF005 module - no generating 40KHz tones, timing etc. Just throw 5V, 0V, a trigger and an echo at it ... simple. The supplied code with the US is simple too. Not the cheapest unit at 12 quid but a bit better than before (used to be 15 I think)

All the best with your project - I think the US would be great for that. I initially was going to go with 10 different lengthed TIG stainless steel rods and pulse them to determine the water level, but the US was less intrusive... less things in the water!!