My Arduino Air Compressor Controller Project – My Parts & Components

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:

Air Compressor Controller Box - 1

Air Compressor Controller Box - 2

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!

Our Electric Grid – Renewable Energy Sources, Part 1

Being in the power industry, and especially since I am currently working at a coal power plant, I get a lot of people asking me about Renewable Energy. More specifically, why can’t we just go to all renewable energy, what’s the hold up? So I’d like to spend the next few blogs in my Our Electrical Grid series to discuss some of the ins and outs of renewable energy.

In 2014, in the US, renewable energy accounted for less than 15% of our total power generation. There are 5 main types of renewable energy sources right now:

  1. Hydroelectric – 6%
  2. Wind – 4.4%
  3. Biomass – 1.75
  4. Solar – 0.4%
  5. Geothermal – 0.4%


Both Biomass and Geothermal utilize the basic steam cycle. A Biomass plant is much like a coal plant, except it has special processes to handle and combust the biomass material. While geothermal extracts its heat from below the Earth’s surface, which is primarily from the decay of radioactive elements. Please review my Electrical Generation Basics post for this topic to review the steam cycle.

Hydroelectric and wind are both similar, as they directly convert their energy source into a rotational motion – The sole purpose of the steam cycle is to cause the turbine to rotate. After the energy is converted into a rotational force, hydroelectric, wind, biomass, and geothermal all use a similar type of generator to convert the rotational energy into electrical energy. You may also review my Electrical Generation Basics post for this topic to review the basics of the electrical generator.

Solar is very different from the other renewable energy sources. It essentially uses a photosynthesis process to convert the sun’s energy into electricity. I will cover this topic in a later post on my renewable energy series.

For my next blog post in this series, it is important to understand the sources of energy for renewables – Biomass, Geothermal, and Hydroelectric are the only renewable sources that provide a consistent source of electricity 24/7. Next week I will be discussing some of the negatives of renewables – Please sign up and follow me, or check back next week for more!

Does anyone know what type of electrical generation source caused the largest immediate death toll? Please leave an answer in my comments section, and I will provide you with some more insight next week!

My Arduino Air Compressor Controller Project – Part 1

Last week, I introduced Arduinos, and mentioned that I would be discussing my air compressor controller project using an Arduino. I will try to complete this series in 5-6 posts with this introduction, details about the hardware, and details about the programming.

Disclaimer: I am providing this information for educational and informational purposes only. Although this looks simple, working with 120V and 240V components and manipulating them with projects like this can be very dangerous, potentially resulting in severe injury, death, damaged equipment, fire, and will definitely void any warranty you may have on the item(s). If you wish to perform a project like this, seek assistance from an experienced electrician first.

So why am I doing this project, when you can just pick up a new stock controller (pressure switch) for $50 – $60? The standard pressure switch for my air compressor typically starts the air compressor when the air pressure drops below 90 psi, and stops when it reaches around 135 psi. It becomes somewhat problematic when trying to run air tools in the 110-120 psi range – when it drops below 100 psi, the air tool just doesn’t get the power it needs, requiring constant adjustment. Yes, you can manually set these pressure switches to cycle on sooner, but leaving it like that will drastically increase the start/stop cycles on the compressor, causing it to ware out much quicker.


My compressor and compressor motor

So, for this project my goal is to create a microcontroller for my compressor that allows me to change the start/stop points of my compressor, safely. The first step in a project like this is to figure out how it works, so you can figure out what you need in order to control it. Normal household compressors are relatively simple – they use a 120 or 240 volt AC induction motor which are controlled by a mechanical pressure switch. The mechanical pressure switch is what I am replacing, so I won’t get into the other aspects of the compressor.

The motor on my compressor is a 240V motor, so it has 2 terminal leads and a ground. The ground is always connected, but the two leads are what the pressure switch controls – it is what my new controller has to do, switch those two terminal leads on/off to start/stop the compressor (it is possible to control it by switching just one terminal lead, but it is just not a good idea as one motor lead will always be ‘hot’).

Now that we know the basics for how to control the start/stop of this compressor, I’ll move on to safety. Most people should already be aware of the hazards of electricity, but this introduces another hazard – over pressurization of the pressure vessel (air compressor tank). I wish it weren’t so, but mechanical and electrical components fail – there is a possibility that the device we use as a switch could fail, leaving the compressor running, over pressurizing the tank, causing it to rupture.

The main key in preventing these bad things from happening, is by getting the properly rated equipment/material. In the image below, you will see my compressor motor is rated for 240V at 15 amps – The switch I use must meet or exceed this rating, failure to do so will definitely result in the switch failing. It is also important to use the proper internal wiring and any other parts/components that will support the voltage and current (amp) that will be flowing through it.

My compressor motor name plate

My compressor motor name plate

Preventing the over pressurization can be done with a pressure release – a valve held shut by mechanical means, such as a spring, that will open at a certain pressure set point to reduce the pressure. The safety relief must be rated for the proper pressure, and flow – it will do no good if the air compressor can supply more air than the relief can release. Most air compressors only output a small volume of air, so most pressure reliefs you find will suffice, just make sure. You can see in the picture below, that my air compressor is rated to output a volume of 10.3 SCFM at 90 psi (at a higher pressure, like 130 psi, it will output a lower volume). Also, it is important to note that the sticker on my compressor states 135 max psi, I looked up the details which state it is capable of 150 psi, and the tank is also rated for 150 psi. So, I need to get a pressure relief for 150 psi or less, that is capable of relieving 10.3 SCFM or more.


My compressor main label

Pressure vessel name plate

Pressure vessel name plate

Next week I will continue posting about this project, moving into discussing the hardware I’ve chosen for my controller. Thanks for reading and following my blog! Please leave comments, and check back next week for more!

Our Electric Grid – Fuel Sources Part 2 (Nuclear Fuel)

In Our Electric Grid – Electrical Generation Basics, I introduced the basic steam cycle in my discussion. In Our Electric Grid – Fuel Sources Part 1, I presented the basics about coal and gas fuel sources. In this part, I am introducing the basics of nuclear fuel sources.

Now I will mention that there are numerous types of reactor designs, including different nuclear fuels, different fuel mixtures, boiling water reactors, pressurized water reactors, and different methods for controlling nuclear reactors. In my future blogs, I will be discussing the GE Hitachi Nuclear Energy – Economic Simplified Boiling Water Reactor (ESBWR), which is one of the reactors I studied for my bachelor’s degree. If you would like me to discuss another type in the future, please let me know in the comments below.


In the ESBWR reactors, uranium 235 (abbreviated U-235). U-235 is actually found naturally, and is mined. Although, natural uranium only contains about 0.7% U-235, the remaining 99.3% is primarily a U-238 isotope, which isn’t useful for reactor fuel. Numerous facilities exist that enrich the uranium by physically separating the isotopes of uranium. Civilian plants typically use 3% – 5% enriched uranium (they are prevented from using anything higher due to nuclear treaties), which is a level that is low enough that it is impossible to create a nuclear weapon with. Theoretically, one kilogram of U-235 can release as much energy as 1500 tons of coal, if it were able to fission 100% of the U-235.

Almost looks like lead or a sort of metal

U-235 – Almost looks like lead or a sort of metal

At the highest level, you can think of the uranium simply as a hot rock. Inside the reactor, while it is operating, the U-235 fuel is fissioning. (In a later blog posts, I will discuss how the process of how fission works in these reactors, safety concerns, and how they are controlled.) The process of the U-235 fissioning produces tremendous amounts of energy in the form of heat. Water is in contact with the fuel rods inside the reactor, which allows for the heat to transfer from the fuel into the water. In the ESWBR plants, the water is actually allowed to boil inside the fuel channel, which creates the steam. From there, it starts the basic steam cycle, as I mentioned in my Our Electric Grid – Electrical Generation Basics post.


I will continue discussing nuclear power in the near future, but next week I will begin introducing some information about renewable energy sources – so stay tuned and leave comments/suggestions!!!

Arduino – Inspiring creativity and innovation of technology through learning

This blog, I would like to talk about one of my hobbies – microcontrollers, specifically, Arduinos.


Arduino Mega 2560

So just what exactly is an Arduino you ask – they are an open-source microcontroller that offers a relatively inexpensive way to learn about microcontrollers and build your own automation systems. There are many other development boards, just to name a few raspberry pi, Intel’s Galileo, even Samsung is getting ready to launch their ARTIK. While these are all great options, I prefer Arduino because there is a lot more documentation and examples available for them, they are easier to setup, and they are an actual microcontroller not a microcomputer (I will discuss the difference later).

What can you do with an Arduino? An Arduino is essentially an I/O (input/output) hardware device that has its own microcontroller. There are numerous different versions of Arduinos, but they range from having 14 digital and 6 analog pins, up to 54 digital and 16 input pins. The digital pins can be used as inputs or outputs, while the analog pins are only for input (except on their Due model, which has a couple of analog outputs). Basically, you use these analog and digital pins on the Arduino to read devices (temperatures, pressures, distance sensors, etc…), then have the microcontroller control a device (servos, motors, switches, send a signal, etc…). Most Arduinos also come with USB connectivity, and have the ability for serial, IC2, and other types of electrical communications – meaning that you can link multiple Arduinos together and to other devices, including computers. Some of the things Arduinos have been used for include:

You can find many, many other projects people have completed with Arduinos, and listed for everyone to see with instructions (

How do you get started, what does it take, how much does it cost? In order to program an Arduino, you need to have a computer with USB – Arduino has their programming software available for Windows, Mac OS X, and Linux. You must download the Arduino IDE (free), from Arduino’s website. Depending on your electrical engineering desire, you can actually get started learning about Arduinos with starter kits that typically start out around $50 (which you can find on Amazon and EBay). Starter kits typically contain one of the Arduino boards (usually the UNO), some electrical components (LEDs, resistors, switches), electromechanical devices (motors, servos), and an instruction manual (could be printed or some are available online). The official Arduino Starter Kit, which is currently unavailable (I believe they are upgrading it), is $89.90. If you’re ambitious, and want to start off on your own, without a starter kit, you can pick up the Arduino official Arduino boards, such as the UNO (one of their most popular boards) for around $25. Arduinos are an open-source hardware/software device, so you can also find a lot of knockoffs for cheaper on EBay, Amazon, and other places. However, I recommend purchasing from Arduino if possible, as they are the inventors and leaders of this project, providing us with continuous hardware and software improvements.

Seeing how quickly our technology is changing, I highly recommend looking into Arduino’s, as it will give you a deeper understanding of how technology is controlling devices – it will give you a new perspective of your electronics. I would also highly recommend them for families – teaching children these things at a fairly young age could be invaluable in their development and potential career paths.

Thanks for reading my blog post! If you are interested in Arduinos, join me next week, I will discuss one of my Arduino projects – a motor controller for my 220V air compressor.

Our Electric Grid – Fuel Sources Part 1

Last blog post I discussed some of the basics about how electricity was generated, and introduced the basic steam cycle. This blog I would like to share some information about the primary heat sources for steam cycles of power plants; coal, natural gas, and nuclear.

Coal Plant1

In order to increase the efficiency of coal, which also helps minimize emissions, coal is ground up into a very fine particulate. This is performed inside of a Pulverizer, which uses large steel balls to crush and grind the coal into the very fine powder. The pulverizer is also combined with a Primary Air fan, which blows a large amount of air into the pulverizer that serves two purposes:

  • Blows the pulverized coal out of the pulverizer
  • Mixes a specific amount of air with the coal fines to increase burning efficiency

After the coal leaves the pulverizer, it is directed into coal burners, which assist in directing the coal, and the fire to maximize efficiency and minimize emissions. At the burners, coal is lit off into fire (initially by a natural gas flame, but the coal fire becomes self-sustaining and the natural gas is removed). The fires heat the tubes inside the furnace, which contain water, causing the water to boil into steam. The steam is then “superheated” by sending it through another heat exchanger downstream from the fires. After being superheated, the steam is then sent to the turbine, starting the steam cycle.


Coal Plant2

There are two different methods for using natural gas – through a gas furnace, or by using a gas turbine. A gas furnace is perhaps the simplest of all the power sources for the steam cycle plants – it is simply done by burning natural gas through burners, similar to how coal is burned after it is pulverized.

The gas turbine is not necessary for a steam cycle, however, they are typically used in conjunction with a steam cycle to increase the efficiency of the gas – these are called combined cycle natural gas plants. In a combined cycle natural gas plant, natural gas feeds a gas turbine, where it is mixed with air and burned. The burning creates additional gasses, and heat, causing the gasses to expand, building up pressure. This pressure from the gas and heat is used to drive the turbine, which also has a generator attached to it. After it exits the turbine, the gas is directed through a water heat exchanger, where it boils the water to steam – this allows these plants to reclaim some of the energy, which would have been lost in the form of heat. Some of these plants also have supplemental natural gas burner elements to aid in controlling and increasing the output of the steam cycle. (,


Thanks for continuing to read my blog! Next week I will continue this discussion of fuel sources, moving to nuclear fuel – please check back, and leave comments!

Our Electric Grid – Electrical Generation Basics

Last blog I shared some basic information about the power grid, which I will expand on later. So for this blog post, I would like to share some basic information about how power is generated, which I will also expand on.

Electricity is created by energy transformation – we are taking one form of energy (chemical, nuclear, kinetic, wind, or electromagnetic radiation) and converting it into the electrical form of energy. The majority of power generation in our country is through the use of a Steam Cycle – Coal, oil, nuclear, natural gas, and others all use steam cycles. Steam systems are actually extremely complex, and very precise, but from the high level view a steam cycle uses a system of components to convert the fuel source into heat, which is intern used to heat up water and convert it into steam. The energy in the steam is then directed through a turbine, which provides kinetic energy to the electrical generator through the attached rotating shaft. The steam is exhausted from the turbine and condensed back to water for reuse. See the image below for a simplified example:


Electricity is a unique, interesting energy source. It is closely related to magnetism, and can be generated through the use of magnetism – simply passing a magnetic field by an electrical conductor, such as a piece of copper wire, will induce a voltage in the wire as the magnetic field passes it. The voltage is only induced as the magnetic field is moving, and ‘cutting’ through the wire. On the other side of that principle, when current is passing through a conductor will actually create a magnetic field. Electromagnets are created by coiling copper wire and passing electric current through the wire. These principle are how we generate electricity in our generators. In most generators, the rotating portion is just a big electromagnet, and around the armature is a bunch of coils of wire. Therefore, as the steam rotates the turbine shaft, it rotates the electromagnet causing the magnetic field to ‘cut’ the wires and induces a voltage – electricity!  This is a simpler drawing of a 1 phase generator:

AC Gen1

Power plants actually generate electricity in 3 phases, without getting in too deep yet, just consider it as 3 different power lines from 1 generator:


In reality, these systems are much, much more complex, but I’m sparing the details for some more advanced blogs later, but I’ll share a little bit for future topics. The generation systems have to maintain a certain voltage output, and frequency, otherwise it would damage our electronic devices. Therefore, there are a lot of additional monitoring systems, protective systems, and regulation systems – the turbine speed is regulated to maintain generation frequency, and the electromagnetic field is also regulated to maintain the voltage output of the generator.

For next week I will be discussing how the different fuel sources get broken down and used to create heat, and I’ll also discuss a microcontroller project I’m currently working on using an Arduino Mega – Follow my blog and stay tuned for more!