Arduino Controlled Electric Blinds

This next project wasn't so much to save energy, as it was something interesting to add to the house. The blinds in out kitchen are always left open into the night, and everyone in the house uses the lights in the morning instead of the natural sunlight. I decided it might be a cool project to under take, and make the blinds automatically open in the morning and close at night. Along with that, I included a push button to open and close them as we please.



The first and most important part of this project is the Arduino micro-controller. It is a popular, open source, platform and there are tons of programming and project examples out there. I picked up mine from Spark Fun, along with a usb programming board.

The Arduino micro-controller works great with the USB programming board, however $30 was a little to much money for me to just stick in a little black box. Luckily all you need to use the micro by itself is a 16MHz oscillator, and two 22pF capacitors. A good guide to breadboarding a stand alone Arduino can be found here.

For the first part of the program, I concentrated on was controlling the blinds with the push of a button. For this you will to be able to read a push button signal with one of the digital inputs on the Arduino. In the program, I set a flag so that I know whether or not the blinds have been opened or closed and have set up 2 digital outputs. When the button is pressed, depending on the open/close flag, the outputs go from both low, to one high for a specified time (however long it takes for blinds to open), then back to both low. Once the blinds are then opened, and the button is pressed again, the output that stayed low last time goes high, and the output that went high stays low. It does this for the set amount of time again, then sets both low, waiting for another button press.



In order for these outputs to control the motors, we need to somehow get the 3.3v, small current signal from the micro, to operate the 5v, larger current motors. To do this, I took the 2 outputs from the Arduino, and ran them into 2 separate Darlington opto isolators. Because we used a 3.3v regulator, we can still hook onto the 5v source in order to control the h bridge and both of the motors. The 3.3 volt signals from the Ardunio outputs, go into the opto isolators which control the 5v that controls the h-bridge, which in turn controls the motors.

When one Arduino output is 5v and the other 0v, the motors turn on and go forward. When the outputs are switched around, the first being 0v and second 5v, the motor goes backwards. When both outputs are 0v, the motor is turned off and does not move.



The great 5v geared motors are perfect for opening and closing the blinds. They have a plastic shaft which can have a hole drilled through for connecting to the blinds. They are easily mounted with the mounting brackets from Solarbotics. I was able to rig up a mount from materials I had around the house, but you can get some materials from your setup at the local hardware store.



Now that we are able to control the motors with the push button, we need to be able to control them with light, or the absence of. To measure the light, I picked up a Light Dependent Resistor (LDR) which can be used with the Arduino analog to digital converter (ADC). Combining the LDR with another 10k resistor in a voltage divider, the ADC reads takes a reading of 3.3v= 1023, and 0v=0. You will have to fiddle around with the actual values from when the sun goes up and down, so that your blinds open and close at the correct time.



Once all these parts are on a breadboard and are working correctly together, you are able to put them all on a circuit prototype board that can fir inside a project box. In the picture of mine, the red and brown wires are going to the LDR, the blue wires to the motors, and the black wires to the power adapter. Because the blinds will open or close any time the push button is pressed, this could cause a minor problem if you have the program open and close the blinds every time the light goes from light to dark or vice versa. Say it is light out, the blinds are open, and you would like to close them. If you leave them closed, then when it becomes dark out again, the micro will sense to close the blinds, only they will open because it will do the opposite action as the last time. You need to compensate for this in your program, which included at the bottom of this post





Parts list
Two Solarbotics GM3 Gear Motors - $5.75 each
Two Gear motor mounting brackets - $1.35 each
Arduino USB Programming Board - $29.95
Atmega328 w/ arduino bootloader - $5.50
28 pin Dip socket - $1.50
Two 22pf resistors - $0.25 each
16MHz crystal oscillator - $1.50
H bridge motor driver - $2.35
Pushbutton - $0.95
3.3v regulator - $1.95
Light Sensitive Resistor - $1.35
5v power supply - $5.95
DC power jack connector - $1.25
Two Opto Isolators - $1.25 each
Prototype circuit board
Project Box

Arduino Light Sensitive Blinds Code


Schematic

Attic Insulation

The attic in our home was never very well insulated and we believed we were losing a large amount of heat from right above our heads. Insulating is a great way to save energy, however doing it correctly takes a good amount of work. In order for your attic to be correctly insulated, it must be able to breathe. When the air in the attic is vented in and circulated, it helps with energy loss in both the winter and the summer.



In the summer, the circulation move out the hot, stagnant air trapped in your attic, and brings in cooler air from outside. This helps you because heat moves from hot areas to cold ones, meaning that if your house is air conditioned or cooled down, the trapped heat from the attic will then migrate into the house, raising your cooling bills.

In the winter, the vents work the same way to move out the dense warm air. If this air is left lingering, it can cause the roof to start rotting from the inside out, and it can also cause ice dams. The proper insulation also keeps heat that escapes from your house, which raises your heating costs.

In order to achieve a properly insulated and vented attic, you will need know a few things. In order to allow air to enter the attic, you need to have what is called a soffit vent. This is a vent underneath the side of your roof that allows air to be let into the attic.

A lot of houses have very small soffit vents, as ours did.



Having 3 or 4 of these small vents does not let very much air into your attic, so the first thing we did was add soffit vents across the entire underside of the roof, in order to allow the maximum air to be circulated.



Cutting the long slots in the roof immediately did wonders for the air flow in the attic, and with the vents secured in place, the holes were safe from the elements.

The next part you will need for your properly ventilated attic is a ridge vent. This allows the air that enters through the soffit vent and circulates through your attic to exit.



For this part we needed to get up to the roof and cut a slit through out the very top. After this was done on a non rainy day, we installed the ridge vent, and re-shingled the top of it, so that no rain or snow would be able to enter the attic. After doing these two steps, our attic was now properly vented.

This was only the first half of the project, and doing this took a little while. We opted to do it ourselves rather then hire a contractor in order to save money, which is the ultimate goal here. We urge you to only undertake this if you know what you are doing, because doing it wrong will only cost you more money in the long run. Now that the ventilation is finished, it is on to the most important part of the project, the insulation.

Before laying any insulation, you must make sure that none of it will block the soffit vents that you just installed. In order to do this, you must install what is called a baffle.



A baffle works by placing a barrier between the insulation and the soffit vent. This barrier is designed for air to be able to come from the vent, circulate through the attic, and not have any insulation block the vent.



Once these vents are installed, you are now ready to lay down the insulation. Thee are different types of insulation, some you can roll on, and some you can blow into your attic, and we chose the to blow ours in. This results in more compact insulation with no air gaps. In order to do this we rented the Owens Corning Atticat from Lowes.



Working it is relatively simple with a 2 man team. The long, included, hose is run up to the attic and is operated by one person who blows the insulation wherever they want to direct it. On the ground level, the other person cuts open the bags of compressed insulation, and pushes it into the Atticat. The machine then does the rest of the work, separating the insulation apart, and forcing it up the long hose and out the other end.



Blowing the insulation happens at a pretty quick rate, but it still took us all day to coat our entire upstairs attic, and garage attic which was above a room in the house. One reason it took us a long time to get all the insulation in, is because we went above and beyond with the amount we put in. There are different levels of insulation, which are regulated byR-Values. Our home was rated with a recommended R-value of 38-49, and as you can see in our below pictures, we went well above the highest value of R-50 on the white strip next to the yard stick.



Before Insulating


After Insulating

After blowing in all the insulation, we have now almost completed the process. Now all that remains is to put some insulation over the entrance to the attic. We chose to block off the blown insulation from the attic opening, so that it would not fall down into the house every time we needed to get up there. Since we did not want to use the loose insulation, we used some prefabricated sheets, and cut them to fit over the entrance.

With that, our attic is now properly insulated and vented. Our energy bills have begun coming in for the frigid winter months, and we will be able to share with all of you how much energy was saved, compared to our energy uses at the same time last year.

Welcome to the Energy Defender

Welcome to the energy defender, the blog dedicated to saving your energy. We will be posting tips and tricks for you to implement in your everyday life. Keep coming back, because more posts will be coming soon.

As always, feel free to contact us at energydefender@gmail.com