Instructables
Want To Build A Motorized Window Blinds Controller For About $15.00? Here is how. I enjoy having potted plants and watching them grow, but making sure they get enough light can be a challenge. I have a bookcase in front of the window in my bedroom with several plants on the top shelf. The window faces north-east and opens onto a small patio so the plants don't receive any direct sunlight. Knowing this, I choose plants that don't require a lot of light. However, they do need some so I have always tried to keep the blinds open as much as possible. My problem is that I often have unexpected things come up in the evenings and don't always get home before dark. That presents a problem. I have several digital clocks, a nixie tube clock, and a couple of other light producing projects around my home. They are not visible from outside during the day, but at night they shine like bright beacons to the world through open window blinds. I know this is a security risk and feel like having the blinds open after dark is like asking for problems.

For a long time I just waited until I got home in the afternoons to open my blinds, but my plants suffered from a lack of light. They were not dying by any means, but they were not healthy, and their growth was severely stunted. I needed to find a way to open and close my blinds automatically when I was not at home.

An automatic blind opener is not a new invention. They have been available for years. However, even the low end models cost in excess of a hundred dollars per window. Some models and styles can cost ten times that much. Most use IR remote controls. Other available activation options include timers, RS-232 interfaces, and light sensors. I needed a controller with a light sensor that would open my blinds in the mornings and close then in the evenings. However, I was not willing to pay what I thought was an unreasonable price for a simple light activated motor. Being the Maker that I am, I knew I could design and build what I needed and do it for a lot less money than what any commercial units cost.

Because I am a big fan of the versatile and inexpensive PICAXE microcontrollers, it was a given that I would design and build my window blinds controller around that chip. I decided to use the PICAXE -08M which is an 8 pin DIP with loads of features including several inputs and outputs, analog to digital converters, a pulse width modulatior, an IR transceiver option, and more features and extras than you would think would fit into its tiny package.

If you have not used PICAXE microcontrollers before I would suggest purchasing the 08M starter pack for around $12.95. It comes with the micro controller, a software CD, a serial download cable, a proto board, a battery holder, and all the basic parts you need to get started with the PICAXE system.

PICAXE 08M Starter Pack

The PICAXE system was originally designed for educational use and is. It is an excellent system for beginners and experts alike. The PICAXE software is simple to learn and use. It uses simple Basic commands that are easy to understand because they actually make sense. You even have the option of writing programs using flow charts. I usually start my projects using flow charts option and later convert them to Basic commands when I start tweaking the program. Best of all, the PICAXE software is freeware. You can download it and all of the manuals from the official PICAXE website.

Official PICAXE Web Site

I must admit that I got a little side-tracked in the beginning of this project. I decided to play around with the IR remote control options built into the PICAXE -08M. It was neat to use an old television universal remote control to open and close my blinds at will, but that did nothing to help solve my problem. I finally found my focus again and went to work designing this project.

After several weeks of electronic hardware, software, and mechanical tweaking I finally came up this design. It is simple, easy to build, does a great job, and is just plain cool. If you have any spare or salvaged parts lying around you can build the whole thing for a lot less than $15.00. If you have to buy everything you can still build this project for around $20.00 including the batteries.

I really enjoyed designing, building, and tweaking this project and I learned a lot in the process. Now my plants get the light they need, my other projects are not shining through the open window blinds at night, and I feel better knowing the blinds will close at night whether I am there or not.

***************************************************************
Be sure to check out the "Take it Further" ideas in step 12.
They are sure to spark your imagination and make you
want to fire up that old soldering iron and get busy
on a truly fun and practical project.
***************************************************************



.

 
Remove these adsRemove these ads by Signing Up
1-40 of 113Next »
Would it be as easy to replace the LDR with a timer to make the blinds open and close on a timer?
biochemtronics (author)  jmarcinkowski1 year ago
I would not say it would be easy but it could be done. It might work great for your application. However, the reason I did not use that method is because sunrise and sunset changes so drastically throughout the year. It gets dark here at 5:30 in the winter and almost 9 in the summer. Given that and daylight savings time changes and you have almost a 5 hour span of time when the blinds could operate when I might not want them to.

Will you build me two of these unit Automatic Window Blinds Controller (PICAXE)

Sorry, but I don't make these to sell.

biochemtronics (author)  jmarcinkowski8 days ago
Yes, a timer could replace the LDR. In fact a timing circuit could replace the entire circuit including the PICAXE.

The Advanced Microcircuits web link on this page no longer works.

tyconway10 months ago

I have a 4th grader that has to come up with the idea for an invention and try to make it work. He wants to invent a system that would remind his grandma to put her contacts in every morning. His idea was a light activated pulley system that would activate when she turns on her bathroom light and drop a reminder note down for her to put her contacts in . Would this kind of motor work with a typical house light or does it have to be sunlight?

biochemtronics (author)  tyconway10 months ago

Yes, this circuit can even be set to activate with any light level; even candle light. Looking at the software program you will see that I open the blinds when the value of 4,b1 (the light dependent resistor or solar cell) is above 240. That is pretty bright. It then closes when the value of 4,b1 drops below 200. Your student needs to experiment and adjust the activation values for the light in the bathroom. A window or nightlight in the bathroom or even the light coming in from another room could activate the motor when it isn't suppose to. Also, using light in the bathroom to activate it means that even if his grandmother turns on the light in the afternoon the little sign will come down. Not sure if that would be a problem or not. The software could be changed to only operate the sign after the room has been dark for several hours but that might not be practcal since people sometime go to the restroom in the middle of the night. I am not sure how this could be done so that it only happens in the morning. Good luck figuring it out.

alfaboy1 year ago
Hi, I've ordere all of the parts in this list except the picaxe. I could not find Advanced Micro Circuits, but found the picaxe starter kit at robotshop.com. I'm assuming I need the USB Starter pack to get the cable and CD for programming it. Let me know if that sounds right.
Also, BGMicro didn't have the REL1090 on its site, so I ordered REL1107, the description is: 5Vdc Latching relay by Fujitsu. 2A contacts, double pole, double throw latching. Coil resistance 178 ohms. Will fit in a 0.3" socket.

Will that work? Or could you suggest a replacement relay I should get?

I'm looking forward to this project, I have a background in programming, and it's fun to see the picaxe is programmed in BASIC, line numbers and all!
biochemtronics (author)  alfaboy1 year ago
Yes, you need the USB cable for programming the PICAXE. As for the relay, the latching relay will work but will require some code changes. The relay I used was not a latching relay. That means that when the power is applied to the coil the contacts change position and when power is removed from the coil the contacts return to their previous state. With a latching relay the contacts change position when power is applied to the coil and the contacts remain in that position when the power is removed. To change the contact position you need to apply power to the coil again. Some latching relays use two coils so you have to alternate power between the two to make the contacts change position. I cannot tell from the description which type the REL1107 relay is. You can either rewrite the code to change the relay contacts bak to their original position or you can get another relay. BG Micro has a REL1106 that will work well fr this. Nearly any regular 5 volt coil DPDT relay will work for this application. I hope this goes well for you.
jeabraham2 years ago
I built your system but the picaxe keeps resetting when the motor turns on. When I shine a flashlight on the LDR it switches the relay, pauses the appropriate amount of time (10ms in your code, but I changed it to 1000ms), then starts the motor. But instead of waiting 6 seconds with the motor going it restarts the whole process. I think the motor is dropping the supply voltage, causing the picaxe to reset.

My proposed solution is to run the motor directly off the batteries through a separate relay, so that it draws from outside of the voltage regulator. Fortunately I ended up with a double relay DS4E-S-DC5V, since I couldn't find the one you recommended, so I'll use the other side for the motor control.

Thoughts?

Also my application is different. I want my blinds at work to close when the sun is out, to reduce glare on my computer screen, but then reopen when the sun goes behind a cloud or a building. I hope to redesign it so the two buttons are used to increase or decrease the programmed setpoint for the desired amount of light. And the algorithm would sweep the blinds from closed downwards through fully open to closed upwards, recording the maximum amount of light that comes in. After determining the maximum available light, it would then close them fully down and gradually open them until it hit the setpoint or the maximum available.
biochemtronics (author)  jeabraham2 years ago
From your description of the problem, it sounds like the motor you are using is causing electrical noise and resetting the Picaxe. Some motors do this and some don't. There seems to be no rhyme or reason to it. The good news is that this is usually easy to fix. To correct this problem you will need to install a noise suppression circuit on the motor. The Picaxe manual recommends installing a 220 nf polyester (non-polarized) capacitor across the motor terminals. I had a similar problem with another Picaxe project I built. I fixed that one by installing three 0.1 uf disk capacitors on the motor. I put one capacitor between the two motor terminals and another capacitor from each motor terminal to the metal motor case. A fingernail file will usually scuff the motor case up enough to solder to it. I feel sure either of these solutions will correct your problem. Best of luck.
Well it's weird, I think it may be the relay I chose. The part you suggested wasn't available, so I chose a DS4E-S-DC5V. Supposed to draw 40mA across the coil when activated.

Even with the motor disconnected, it still resets once in a while. I've used 2 relays now, and have connected the motor (and the switching sides of the relays, of course) to a completely separate power supply. The only thing the PICAXE is doing (through the darlington array) is switching these relays.

Still, it resets now and again. I bought parts for two devices and have been swapping them in and out to try to blame manufacturing inconsistencies.

Oh yeah I have three 220nF capacitors across +5V/Gnd, without these it doesn't work at all, just resets all the time.
biochemtronics (author)  jeabraham2 years ago
jeabraham:

From what you describe this still sounds like electrical noise in the circuit. It could be coming from the motor and/or relay coil. I have two suggestions.

1) Put a 220 nf polyester capacitor across the relay coil to suppress any noise coming from it.

2) Try operating the circuit on battery power. If you have to add capacitors to the 5 volt supply it must be really noisy. If the circuit operates fine on battery power then you need to either change power supplies or add several thousand mfd of capacitance to the output.

I hope this helps.
Thanks, I tried the 220nf across the coils again just now, didn't help, but I tried them together with 120ohm resistors to ground on the one coil side, and it may be working now. Sort of a low frequency filter.

I am on batteries. Well, my electronics are on batteries. The motor is being powered by a cannibalized 5V supply, but it's completely electrically separate now, being switched by the relays.

I've also ordered some other relays off of ebay, just to try them.

If only I had an oscilliscope to see the noise pattern.

My program is super cool by the way, I'll post it when it's all working. I couldn't rely on the blinds making the motor stall out at the end of the rotation, so I have to avoid that by tracking my "position" as the total time spent swiveling each direction. To avoid drift I'm resetting it every 12 hours or so that the midpoint is the location where the maximum light was observed. So it's getting complicated.
biochemtronics (author)  jeabraham2 years ago
I also forgot to mention that you need to place a diode across the relay terminals to shunt the kickback voltage it produces when the power is disconnected. Just make sure the diode is in the reverse polarity or it will short out your circuit. Your program sounds really interesting. I cannot wait to see how you accomplish this. As for an oscilliscope, I am seriously considering one of the new digital deals. Maker Store has one for $110.00 and you can get similar ones from other sources for a few dollars less.
Awesome tutorial! I'm gathering supplies to make one myself! I just ordered that PICAXE 08M starter kit, but am curious.... does it come with the IR transceiver right out of the box, or do I need to order it separate? I like the light activation, but that isn't really suitable for my circumstances. The remote controlled idea sounds awesome though! If I can get one to work correctly, I'm going to build one for every room in my home :)
biochemtronics (author)  reverbflange2 years ago
The PICAXE does not come with a IR emitter or receiver. You will need to order a receiver separately. As for using the remote control, a word of warning. You may run into problems getting the remote to work if you are dealing with direct sunlight coming in your windows. It has to do with the IR in sunlight overpowering the weak IR coming from your remote. I had a toy helicopter that used an IR remote. It was pretty useless outside or in front of a window with direct sunlight coming into it. Best of luck with your build.


mart_19865 years ago
hi there

im a newbie to electronics im really intrested in this idea.how would i put it on a timer as i need it to open at 10am and close at 6pm every day for 12weeks each year (its for my racing pigeons)
biochemtronics (author)  mart_19865 years ago
 For a timed application I would just use a power supply and a household timer. The full open and close positions could be controlled with simple limit switches.
I would also like to do a timed application. What if I adapted your design using the 08M2, removing the light sensor, and adapting the code to use the time variable to count the seconds between opening and closing? That would at least be a start, but I wonder if it would work, or whether the time function would use too much battery power.

You mention using a household timer, but I have never done any circuitry before so I'm not sure where to start with that. Using the 08M2 would allow me to follow your design fairly closely.

BTW, I want timed blinds to help keep the house cool in the summer and to help wake me up in the morning.

Any tips would be greatly appreciated! If I figure something out I'll post the solution here.
ravonricks2 years ago
Well Put together project!! Do u have a larger schematics?
niftyswell2 years ago
To open and close you need two solar power sources. The first one would be a standard source that has a cut off actuated by the blind itself when if fully opens- a fan pull toggle switch would work just fine. The close would require you to get a simple 3 dollar solar light from a department store that has the battery that charges during the day. Again, the close action would actuate the power to stop flowing. You have to ensure the open and close triggers are consistent enough not to trigger both at the same time which should be simple enough to achieve by simply using the blinds themselves to interfere with the electronic eyes. Then the only issue you would have is the battery running out of juice keeping you from actuating a close sequence...but it would use such a low amount of juice the battery should last for quite some time.
mongorsf3 years ago
Anyone familiar with solar cells, I wanted to do this project but using solar cells to start the motor to open the blind and keep tension on a spring loaded pully all day while the panels had light and gave charge to the motor. Then the motor would release the tension once the sun went down and it lost its voltage, allowing the spring to release.

The motor he listed above is 3v, that would only take 6 3x6 panels at $.60 each (typically), removing the need to change batteries and would only open on days that were sunny enough to deserve the blinds to open. 6 panels would give only 12 watts of power, but if geared right should be enough to slowly open them.

The only thing I worried about is that it might burn out the motor keeping a charge on it all day, everyday, no?
biochemtronics (author)  mongorsf3 years ago
Keeping current on the motor all day would not be a good thing. It would damage the motor for sure. However, you could replace the batteries with a bank of solar cells and add a slight delay so that they get full sun and build to full voltage before powering up and starting the motor. You would also need to start closing the blinds before the sun goes down in the evening so the solar cells would have enough power to operate the motor. Another option would be to use a couple of super capacitors in the circuit with the solar cells instead of batteries. If you use 3 or 4 of they should hold enough power to open and close the blinds. Also, don't leave out the voltage regulator. It only takes a few extra millivolts to kill the picaxe.
First, thank you for your reply.

I think you might have misunderstood my goal.

You are talking about delays, capacitors, circuits, etc.

But I am looking to have NO circuits, batteries, or light sensors to determine when they open or close. (I don't think I would even need the voltage regulator because the cells are not capable of generating more then 3.2v in the brightness sun.) I was thinking that I might use a DC to DC boost converter to keep the voltage at 3v as long as possible.

Due to a spring on a pulley line, the natural state of the blind would be 'closed'. When the sun hits the panel, it puts voltage to a motor, pulling the line, stretching the spring, and holding the blind open. If it gets cloudy or sun goes down, there would not be enough voltage going to the motor and it would lose power and the spring would take over and pull the blind back to natural state of 'closed'. So as long as the solar panel outputs voltage, the motor has power to fight the spring.

The motor would be geared and open VERY VERY slowly with the small amount of power the solar is giving it, so the motor would really not have that much constant power going to it. I am guessing 3v with 12w at the sunniest part of the day.

Is there any type of motor that can handle the constant voltage or maybe some other idea similar to this.

Thanks,

Gary

$10 a motor
3v -3 rotations per min- (very slow eh)
http://www.ebay.com/itm/3V-3RPM-Torque-Gear-Box-Motor-New-/260793928051?pt=AU_B_I_Electrical_Test_Equipment&hash=item3cb8878973

or 3v 10RPM
http://www.ebay.com/itm/3V-10RPM-Torque-Gear-Box-Motor-New-/220765783849?pt=LH_DefaultDomain_0&hash=item3366aa8729#ht_4685wt_952

Boost converter (but I need to find one that will do 1.5v to 3v)
http://www.ebay.com/itm/300601910406?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_3634wt_952
biochemtronics (author)  mongorsf3 years ago
Gary:

I did understand your goal.In theory the method you are talking about using would not need anything more than a bank of solar cells, a spring and a motor. However, I do not think there is any way to do it this may for a couple of reasons.

First you cannot allow current to continue flowing through a motor when it is stalled because its inductive resistance drops dramatically when its stops turning. The motor windings will then act like a short circuit and the current flowing through them will increase and cause them to heat up and fail. There is no way around this. If you limit the current so this doesn't happen then there won't be enough to start the motor. All motors use several times as much current to start as they do to run. Also, all motors pull more current when the armature stalls. If the solar cells you are using can supply enough power to start the motor they will supply enough current to damage the motor if it stalls.

As for using a spring to return the device to the original starting position once the motor looses power, it sound good in theory but I don't think it is likely to work for this reason. When the motor is opening the blinds it is also going to have to wind up and hold the spring as well. This is going to dramatically increase the needed electrical current and the motor size needed to overcome the friction of opening the blinds and the current needed to overcome the spring pressure. That is going to require more solar cells to increase the current and the additional current will only serve to fry the motor faster once it stalls.

Also, you mentioned using a very slow gear motor. That will work great when it comes to opening the blinds but it is going to present a serious problem when it comes to letting the spring close them. The best way to understand this is to take a small gear motor and try to turn it using pliers on the output shaft. This is what you are thinking about trying using a spring on the output shaft. With a 1 to 3 rpm gear motor you are going to damage the gear motor before you get it to turn using the output shaft. I cannot even turn the gear motor I used in this project using the output shaft without using excessive force.

I hate to be such a skeptic and I do not want to discourage you but I don't think this is going to work. Perhaps there is some other way. A slip clutch on the gear motor output shaft may prevent the motor from stalling once the blinds are open. The motor could keep turning and keep tension on the shaft until the sun goes down and you loose power. However, even with that you are going to have to get the spring to turn the output shaft in reverse to close the blinds. Again, the extra power needed to wind up the spring to this incredible torque (for such a small motor) is going to be a limiting factor.

You have some really great ideas and I am sure there is some way to do this simply. I just don't know how. I suggest you get some motors, solar cells and springs and give it a shot. Even it it doesn't work you will gain some knowledge. Best of luck and please do keep my informed.
You have given me food for thought and some direction to my challenge.

I think with a small guide on my line that would flip a manual switch at a certain point and have it shut the motor off at least I can have the blinds all nicely opened and the sun shining in when I wake up. Then just use some sort of quick disconnect that I can release the line manually at night.

If what your saying is that once the slow gear motor is off, it wont turn back on its own, then I just have to make the spool that collects the line, be able to 'pop' off the shaft and unravel the line, then 'pop' it back on once the blind is down, resetting it for tomorrow.

halfway is better than none :) (for now)

Thanks again
arbayer3 years ago
Sorry I am fairly new to all this... But would it be possible to set it up to a clock of some sort rather than the light dependent resistor? for example set it so they open every morning at 8:00 a.m.? If you have an idea of how that would work please let me know. Thanks!
I used these plans to build a chicken coop door opener like Vasileiosh did. However, I used the GM3 motor to lift the door. A few changes to the plans I made were: 1) I tied pin number 3 to ground with a 100K ohm resistor. (I believe living the inputs floating can lead to battery drain). 2) I also added the following lines before the readadc command disablebod sleep 26 enablebod Essentially this puts the microcontroller into low power sleep mode for ~ 1 minute. 3) I used a bobbin (the reel in the bottom of a sewing machine) to wind/unwind string to the door. I tried a larger reel but the motor did not have enough torque. 4) I shielded the lifting mechanism and string with hardware cloth. My chickens are very curious and tend to stand on or peck at something new. I hope this helps out anyone else trying to use these plans to make an auto opener for their chicken coop.
Hello There,
This is really awesome.
Could you please give me the plan and instructions how to build this, I wanted one for my coop, your help is really appreciated.

Thanks
brbd@hotmail.com
batman963 years ago
I was thinking about one that would work with my alarm clock, also it won't use any microchips. It would have a latching diode or relay in line with the alarm beeper, when it beeps it would roll up the blinds using a geared down motor from a tape deck, when it gets to the top it would push a normally closed button to shut off the latching diode or relay.
Any other ideas or suggestions would be appreciated!
thanks
Jakeg4 years ago
Hey there, I would love if you could get in touch with your friend to get more info on those motorized shades. I want to do thin in my house but i don't want to spend over $100 for the store bought version. Please help. -Jake
biochemtronics (author)  Jakeg4 years ago
He said that he used a pully that came with the shades. It was made to mount at the bottom of the window to keep the string tight. He says it is a beaded string, not a regular string. For regular string any sort of spool or pully that would mount easily to the motor shaft would work. Perhaps you could check the solarbotics web site and find something there that may work like a wheel made to fit the motor shaft. You could always glue or screw a wooden spool to the wheel and wrap the string around it. Best of luck.
bneese4 years ago
I am going to attempt to do this on 2 blinds we have in our vaulted great room. I do however need some advice. To open and close my blinds you pull on 1 of 2 strings. How could I accomplish this?
biochemtronics (author)  bneese4 years ago
A friend made one of these for some window shades. They had 2 strings that operated the shades. He mounted a pulley (similar to a small thread spool) on the motor, tied the shade strings together, and wrapped them several times around the pulley. When the motor turned in either direction it would pull on one string while unwinding the other. It worked great for him. Hope this helps.
kd5crs5 years ago
Well, I had a whole big comment detailing my experience, but the website ate it. To summarize: 1. It works great. 2. I used the IR sensor for control. 3. I used a reed switch to say when the blinds are open, removing the need for the buttons or fiddling with timing. 4. The motor controls the shaft inside directly, rather than through the worm gear on the hand-turn rod. That improves battery life, speed, and reduces load on the motor to almost nothing. 5. Everything fits inside the box at the top of the blinds except the batteries, which I am keeping accessible until I know how long they last. I'm using 2" blinds. 6. Thanks for the awesome project, and 7. Time to automate the other blinds in the house!
bneese kd5crs4 years ago
kd5crs. This is what I would like to do. Do you have any documentation on how to go this route? My blinds use 2 strings to open and close, so I would like to be able to do it directly from the shaft. Plus these blinds are going to be in the vaulted great room so I would like to use a remote. I have never done anything like this before so please forgive me if I am a newbie. Any help you can give me would be great! thanks.
biochemtronics (author)  kd5crs5 years ago
I like your modifications. I plan to incorporate them into my next blind control. Thanks for sharing this with us.
Thanks. My first one has been in use for a month now, and I've made some upgrades. I have three total in operation. 1. I replaced the reed switch with a contact switch. Simpler, more reliable, and keeps everything contained in the top of the blind. One input for closed, one input for open, and a piece of metal taped to the blinds that is connected to 5V. When it closes the circuit, the input goes high, and the blinds stop moving. 2. Battery life is not great. It's made worse by the fact that they start behaving unpredictably when the voltage gets low. Did you ever add a low voltage indicator? I'd like to add that to mine, but I'm not sure how.
1-40 of 113Next »