Remotely monitored distillations using a Pi

I have managed to remotely monitor distillations using a Raspberry Pi, a £2.55 waterproof temperature sensor, RF controlled plugs and an equally as cheap 433MHz transmitter and receiver set.
Works really well, I managed to distill ethanol in my garage remotely from my house several times. I only needed to visit the garage to change the sugar wash in the boiling flask.
The temperature sensor was wired up to the Pi after soldering a 4.7k resistor between data and vcc.
The remotely controlled socket was a bit more difficult, I had to connect a 433MHz receiver to the Pi then press the On and Off buttons that was provided with the sockets in order to sniff the codes sent by the remote.
Once I had the codes which the remote uses to toggle the plug on/off I could attach the DS18B20 temperature sensor to the Pi along with the 433MHz transmitter. I then plugged in my 3G dongle in order to connect to my Pi in the garage as the WiFi doesn't reach there.
Then I wrote a couple of simple python scripts allowing me to fetch the temperature of the sensor, turn the plug on and off and log the temperature and time every 3 seconds. Finally another script which would repeat a cycle of switching the hotplate on for 60 seconds, then off for 30 seconds whilst the temperature was less than 98°C


After I wrote a script that converted the data into an Excel document then plotted a graph of each of the distillations.
The first one was the distillation of the sugar wash

Then, as it became more concentrated

The vapour temperature slowly creeps down to 78 after a few distillations meaning we have reasonably pure ethanol.

This is a small proof of concept and I know my apparatus is pretty ghetto but this could be massively scaled up for example for fuel distillation.

[Edited on 17-2-2018 by Big Boss]

Quote: Originally posted by ninhydric1

It would be handy if we could set this up so that when the distillation reaches a certain temperature, it shuts off the heat source, stopping the distillation. Then distillations could complete without having a person attend it. It wouldn't be useful if, for ex., the distilling flask starts sludging up the adapter, because the distillation would be ruined.

I have done that, I'm not sure why you think I didn't implement that but yes whenever the vapour temperature reaches 98C I send the off RF signal to the socket twice.
And you're absolutely right Nemo, in fact here is the code for my main script. It's ridiculously simple.

Quote: Originally posted by Big Boss

I have done that, I'm not sure why you think I didn't implement that but yes whenever the vapour temperature reaches 98C I send the off RF signal to the socket twice. And you're absolutely right Nemo, in fact here is the code for my main script. It's ridiculously simple.

I think he misunderstood the off part, what I was trying to say was, once you can communicate with the pi remotely, then the switching on and off is entirely upto you.

You could do ultra fine PID controlled fractional distillations, or add a pump to auto top up, the hard part is getting comms when you cant get a wifi .

nice way around that BTW .

Is it the PI3? I got a couple of 2B's, I am thinking of getting the 3, with that you can stick the OS on a USB drive from start up!!

So no card needed at all!! i get through cards on the pi2.

No end to tweaks you could do now. But great project, i like that alot.

Quote: Originally posted by Big Boss

Yep it's the Pi 3, I didn't even know you could load an OS from the USB with the 3 that's pretty neat. nice suggestions btw they would be really easy to do, I got 3 remotes from ebay for £13. I didn't even need to write a lot of difficult code either, the hard part was trying to solve the issue of noise from the cheap RF receiver so I could decode the signals. Have a look at the rpi-rf library if you're interested.

Great project ... well done.

Does the controller in the garage sequence down power if communications are lost ?

How would you know if your garage is on fire ?

Quote: Originally posted by ficolas

Really cool, I am working on something similar and more extensible, but the project is going very slow mostly because of a lack of time.

Quote: Originally posted by ficolas

An idea, by storing the temperature values, and a way of telling how much distilate comes over, like a balance, you coul make a small script to stimate the concentration of the distilate

Quote: Originally posted by aga

Excellent work ! Very impressive. Love the graphs. Quote: Originally posted by ficolas   Really cool, I am working on something similar and more extensible, but the project is going very slow mostly because of a lack of time. Yep. Same here. Only been about 4 years so far and hardly any progress. One device i had in mind was a servo, so the vac adapter could be moved between a waste container and the collection bottle. That was specifically for ethanol to automatically discard everything below 78 C, collect the main flow, then discard any higher boiling components.