Hello everyone! Thanks for coming back for more about my Arduino Air Compressor Controller project!
Before we start building, it is extremely important to come up with a plan! So, I’ve specked out my air compressor system in my previous post, My Arduino Air Compressor Controller Project – Part – 1. It is a 240 Volt motor, rated at 15 running amps, with a tank & compressor rating of 150 psi, but I didn’t mention that it is plugged into a 30 Amp circuit. The circuit breaker is important because it is an important safety feature – the motor runs at 15 amps, but according to the name plate can draw up to 93 amps if it locks up. Therefore, we want to make sure that all the components that we use for the motor will handle at least 30 amps, which is allowed because the breaker trips at 30 amps, protecting everything else in the line.
So, I’ve specked out the components I will be using for this project, in accordance with the ratings I am working with:
- 12 VDC mini/micro fan – This is not necessary, but I thought it would be neat to add it to this project, to show how you can monitor temperature and control it with a fan or other device
- 16 X 2 LCD – You can use different displays, even a touch screen if you wish, but this is a simple display that will work fine to display information, such as the current pressure, and use for operations to change the pressure set points
- Arduino Mega – This is the microcontroller I chose to use – there are others, such as the Arduino Uno, which is cheaper, but I have a couple of these on my work bench, and I just chose to use what I have
- Arduino Mega Shield – This as a great development tool, that allows you to put some small components on a breadboard that fit right into the Arduino headers. There are different variations, some for cheaper, but I like this one because it has the power headers and other benefits
- Nuts/bolts/screws/spacers – This will all depend on the specific configuration of devices you use. I waited until I received all my components, and went to the hardware store with them to get the right size bolts and spacers – The air compressor vibrates a lot while running – everything in the controller box must be secured well!!!
- Power Supply – I chose to use an old 12 vdc 1 amp power supply I had laying around – When picking the power supply, it is advisable to pick one that will supply the highest voltage needed (and of course the necessary amperage), in this case the 12 vdc relay and fan – It is easier to drop the voltage down that raise it up…
- Pressure relief – This is necessary to prevent the air tank from over pressurizing and rupturing, I got a 150 psi relief because it is what my tank is rated for – some tanks are rated for less, such as 120 or 135 psi – make sure to check the rating of your tank before changing out any pressure relief valves
- Pressure Transducer – This is the electrical component that will sense the pressure in the tank for us, and send a signal back to our Arduino microcontroller
- Project Box – There are numerous types, shapes, and sizes of boxes you can order. I just ordered a standard shaped box that will fit in the location I want it to go, and is large enough to fit all the electrical components inside
- Push Buttons – These buttons will be used to enter a menu and change the pressure set points – again, there are numerous types, but for this project I am using normally open momentary push button switches
- Relay – This will actually be the switch for the motor, so the one I chose is rated for 240 VAC and 30 Amps – which is the voltage the motor will be running at, and the amp rating of the circuit breaker it will be connected to. This relay also operates (switches) on a 12 VDC signal, which will work great with our 12 VDC power supply
- Resistors – For this project, we will need some various resistors.
- Temperature/humidity monitor – This component is not necessary, but I thought it would be neat to show a method we can monitor the temperature inside of the box, using the indication to cycle the cooling fan when needed
- Terminal Strip – This will be a handy strip to secure our power leads to
- Transistors – The Arduino Mega we are using is only capable of outputting a max of 500 ma at 5 VDC, which will not power the relay or the fan. Therefore, we will be using transistors as switches for the relay and fan, which will be controlled by the Arduino. These transistors I selected are rated for up to 60V and 5 amps – more than enough for the relay and fan
- Voltage Regulator – The Arduino Mega has a voltage regulator built into it, and we can power it directly from our 12 VDC power supply, but I chose to have a voltage regulator anyways – if needed it will supply more 5 VDC power than the Arduino is capable of outputting
Note: I have no affiliation to any of the links I have provided in this post. Most of the components I have for this project, I have acquired over time, through eBay, Amazon, RadioShack, and other sources. I have just provided these links for your benefit, but you may be able to find better deals by Googling or using other search engines and sites.
Here’s what my box is beginning to look like after starting to securely bolt the components in place:
Thanks for joining me again! Next week I will post some more progress with the basic design of the controller – Please follow me or check back again soon!