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Making Yoghurts With A Raspberry Pi

Sat Dec 05, 2020 3:54 pm


I don't have any coding experience, nor any experience with the raspberry pi. I get the basic concepts of IF, THEN, ELSE blah blah blah...

With that clear here's the idea:

I'm going to buy a dairy farm and I want to make yoghurts. To do this I need what amounts to a box that stays at a steady temperature for about 5 hours. I could either buy a machine that would set me back a few thousand euros, or I could get my hands on an old fridge (the kind of thing they have in shops where you open the door to take what you want), put a heating element and maybe a fan and try to make one myself.

That in itself shouldn't be difficult, but in order to have a consistent product I need a consistent temperature.... So I thought to myself "I've heard a lot about the raspberry pi, maybe that could work".

So, an old fridge, a heating element, a fan, a raspberry pi, and a thermometer... Can it be done?

In my head I imagine typing "IF temp >= 45 THEN power=0" but I suspect it would be more complicated than that.

So essentially I would like to know just how user friendly the raspberry pi is to use, and whether I could use it to control the power supply to a heating element and a fan, using the input of some kind of thermometer (I guess by USB or something...)

Thanks a lot

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Re: Making Yoghurts With A Raspberry Pi

Mon Dec 07, 2020 11:59 am

I'd suggest you have a look at the excellent BrewPi.

It is software used to brew beer by controlling the temperature. They have a guide on how to convert a fridge in to a cooler/heater.

The easiest temperature sensors to connect to the Pi are the DS18B20 devices. They are readily available and come in a variety of different sorts including ones packages in food safe/waterproof cases. DS18B20 devices are wired directly to the Pi's GPIO pins. There are lots of guides available online describing how to use them.

Also read ... -computing This will give you an intro in to controlling outputs/reading inputs using Pi and python. From a software perspective, controlling a heater is no different to controlling an LED.

Usual words of caution: Don't deal with mains electricity unless you a competent enough to do so. Seek professional advice.
A 12V heater might be all you need depending on the size of pots you are heating
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The Traveler
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Re: Making Yoghurts With A Raspberry Pi

Mon Dec 07, 2020 1:45 pm

Get a PLC, Programmable Logic Controller. It will be simpler, easier to program and more reliable: ... controller
RPi interests: Coding an Infinite Improbability Drive. In C.
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Re: Making Yoghurts With A Raspberry Pi

Mon Dec 07, 2020 7:08 pm

A simple microcontroller, PICAXE, Arduino, etc, will probably be the cheapest and simplest option.

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Re: Making Yoghurts With A Raspberry Pi

Mon Dec 07, 2020 7:18 pm

If you are qualified to do this type of work this guy's video well help you out. I know this is a deep frier however the principlas are the same. he goes through it fairly well.

MAINS VOLTAGES CAN BE LEATHAL! If you don't know what your doing please hire someone that does.

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Re: Making Yoghurts With A Raspberry Pi

Wed Dec 09, 2020 8:28 pm

Thanks for your replies everyone. Not sure what I'll end up doing but I have the time to read up and think about it.

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Re: Making Yoghurts With A Raspberry Pi

Thu Dec 10, 2020 3:48 pm

As someone else mentioned, you could look at the brewing world. Home brewers use a device to control the temps for brewing and serving. Many make Kegerators, which consist of an old chest freezer and a temperature control unit. Hook the unit to the wall socket, plug the freezer into the control unit, put the probe in the freezer, preferably in a container of water to avoid temp spikes, and set the controller to the desired temp. You should be able to find something like this, either at a local home brew shop, or at any of the many ones online.
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