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I am completely new to Raspberry Pi and would like to hear your input on this project that I need to solve. My question is: What hardware do I need, how would I connect it and how would I solve the software?

We are a small Electronics Manfacturing firm trying to solve this task: we need to bend wires in a special shape. For this we have manufactured a CNC milled metal piece that will hold the wire. We want to heat this metal piece up with a hot water heating system to reach 60°C and then we want to cool it down to 20°C with cold fresh-water.

What do I need to do?

  1. User presses a Button
  2. Raspberry opens electric water valve (12V) of the heating stream
  3. Raspberry turns status LED to red
  4. Raspberry waits until the temperature measuresd at sensor reaches 60°C
  5. Raspberry closes electric water valve for heating stream and opens electric water valve for cooling stream
  6. Raspberry waits until the temperature measured at sensor reaches 20°C
  7. When temperature of 20°C reached fresh water valve is closed and LED turned to green

What I need:

  • Power two 12V electric water valves
  • Measure temperature with temperature sensor
  • Button
  • Green LED
  • RED LED

Optionally:

  • LCD Display returning the current temperature and status

closed as too broad by Piotr Kula, Ghanima, RPiAwesomeness, goldilocks Nov 27 '14 at 15:39

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • 2
    A Raspberry Pi could do that. Whether you need the power of a Raspberry Pi is another matter. Really you are asking for advice on hardware purchase. This forum probably isn't the best place to advise on hardware. – joan Nov 26 '14 at 19:55
  • Yea and what Joan said. It this question is gonna get closed very quick. If you need help, check my profile and contact me. This is incredibly simple to do with Arduino. – Piotr Kula Nov 26 '14 at 20:02
  • Regardless of which system you use, how much power do those 12v water valves need? do they require a special controller? – user2813274 Nov 26 '14 at 21:51
  • Hi and welcome to the rpi exchange! You have some good questions, plural, here. It would be better if you broke them up so we don't have some people answering some parts, etc -- this makes it more useful for posterity. E.g., "How to power and control two 12V electric water valves?" is fine by itself. Some of the other things (e.g., using a temperature sensor with the pi) you will find more basic information by searching first ("raspberry pi temperature sensor"), which will enable you to ask a more specific question if necessary. – goldilocks Nov 27 '14 at 15:43
  • TEchnically this is possible but you'd have to make a custom PCB connected to GPIO and use some relays to steer the high power stuff. Then you'd have to write own code to control the PCB you made. While making this is possible, it would take lot's of time. You said you are a small technology company. There are spceial controllers to do this kind of job. – thekiwi5000 Nov 28 '14 at 20:33
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Nope. Raspberry Pi is not "that" reliable for production.

Arduino is much better and definitely much more reliable. You can do it with maybe a hundred lines of code at most and it has libraries to do interface with a ton of hardware. Plus once you prototype it on a Mega or Uno it cheap to programme, new stand alone boards on cheap 2 layer PCB (I recommend seeedstudio, cheap PCB's)

You can THEN use the Pi to talk to the Arduino via UART or SPI and host a web page if you want. Pi sounds good but long term, you will face allot of unexpected problems :(#


Micro Controllers, they used every where! Fridges, microwaves, heating systems, cars, bikes, some toasters, PC's, Macintosh, iPhone, Android, Nokia 3310, Nokia Lumia, Raspberry Pi HD camera, tvs / monitors, health equipment like cardio vascular implants, Everywhere!

Even in the BCM Processor, a version of a MCU kicks of the "System On Chip". The BIOS on motherboards is initialised by proprietary MCU's to kick off the OS on the PC. Has any of that ever concerned you? Has it crashed? needed updates? Nope.

Processors are required today run operating systems that need more processing power and flexibility, like on the Pi or Smart TV's and iphones/android. They are prone to heartblead, malware, viruses, corruption, ram failure, bla bla bla.

Dont get me wrong. I love the Pi as small computer thing. It would make a great front end for 10 of these devices the OP builds with MCU's.

Arduino happens to be very mature, popular, and compatible with crap loads of hardware (code wise) is cheaper and is definitely MORE reliable in doing the same thing over for 10 years without failing, than the Pi doing the same without some interruptions and wont last 3 months.

Sure, Micro controllers like atTiny or atMega are 8mhz or 16mhz and cannot decompress a JPEG. But that is not required. There are newer MCU hybrids with 32mhz - 96mhz frequencies if you needed to analyse a bitmap a zillion times over without getting a blue screen or hacked by heartbleed.

I talk from experience and the fact that MCU are so transparent in our lives today is because they just work. I am NOT trying to sell more Arduino's or PIC's and defer people away from the Pi. I want poeple to buy more Pi's and buy my book about Pi's.

But the PI is just not the solution to the OP's problem and even if he got there he would regret using the Pi. I am not going to pretend like a it is by providing him false hopes and maybe answers. And as it turns outs the OP knows exactly what he wants to do he just started on the wrong Q&A.

  • Have you any evidence that the Raspberry Pi is less reliable than an Arduino? This sounds like FUD. – joan Nov 27 '14 at 11:06
  • Why does it sound like Fear Uncertainty and Doubt? Do you think I get paid to chase people away from Pi to Arduino? No, I dont even get paid to answer all the questions about the Pi on this forum or any other SE forum. Maybe you get paid to to comment like you did when somebody like me suggests NOT to use a Pi? Seriously annoying comment about the FUD. – Piotr Kula Nov 27 '14 at 13:07

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