AUTOMATED BLIND

Question

Am having a project to deliver in two months time, the project is about automated window blinds. Am good in computer programming but not actually good in electronics. I need assistance please.

jw0752 · Answer

Hi Benny For everything electro-mechanical that is created there isn't one path to success. Your imagination and your available technology will determine how you get the job done. That is why it is difficult to tell you what components you will need. Try to break the system down into pieces and make the individual parts work and then interface them. I am not sure what an LM35 is and perhaps the LDR is a low dropout regulator. You will need a power source for the motor that is separate from the Arduino's power suuply. If you do want to power both the Arduino and the Motor off the same supply you will need a regulator and filter capacitors to make sure the Arduino get proper and clean power. The arduino will not be able to switch the motor on and off by itself. It will need a transistor that it can control that in turn will turn the motor on and off. The transistor will need to be protected with a flyback diode. If you are going to want the motor to rotate in both directions you will need a circuit called an H Bridge. An H-Bridge will allow the arduino to turn the motor in a CW or CCW direction as well as brake or stop the motion. The break down of your project might be: Arduino and software to interpret your input switch or switches. You could have one button to open the blinds and a second to close them. Or you could have one button that alternately opens and closes. Your software will have to accommodate switch bounce. The is where switches do not make a perfect closed contact immediately and the Arduino is fast enough to misinterpret this as multiple pushes of the switch. H-Bridge and Motor circuits. Here you will want to make sure that the H-Bridge powers the motor and that simulated input to the H-Bridge does what you expect it to do. This will also give you information on what will be required from the Arduino as Outputs to make the H-Bridge work. Motor to Blinds mechanical. Here you will have to devise a way for the motor to provide the power and motion necessary to open and close the blinds. It may be necessary to gear the motor down so that there is enough force to move the mechanism and also to slow it down so that it doesn't happen too fast. If you begin to work on this you will learn a lot and have a lot of fun. If you have questions someone on the Forum will try to help but we work best when you already have a partially working circuit and can give us drawings, pictures and schematics of what you have done. John

kulky64 · Answer

Please, if there is another component that is needed for the system you can let me know.

Maybe some limit switches or some other way to detect if the blinds are in their extreme positions.

Another question is since am going to be using an H-bridge, is there any need to use a transistor and a diode that will be needed to protect the circuit for flyback charges from the motor.

Depens whether you will be using L293 or L293D. From page 7 of the L293 data sheet (www.ti.com/lit/ds/symlink/l293.pdf):

"On the L293, external high-speed output clamp diodes should be used for inductive transient suppression. On the L293D, these diodes are integrated to reduce system complexity and overall system size."

If your motor draws less than 1A (or less than 600 mA for L293D), then you don't need any transistors.

jw0752 · Answer

Hi Benny, Here is a post from 2014 that may have some ideas for you. You may be able to find other posts about Shades, Curtains, and window treatments by searching the E-14 Forum. Otherwise you will have to frame up your idea better and present it with specific questions so we have something to work with. As it is now it is too general.I look forward to following your progress. https://www.element14.com/community/community/experts/benheck/blog/2014/03/28/arduino-powered-curtain-automation John

bodhi_94 · Answer

The article on ben hack show is very helpful to you element14's The Ben Heck Show .. Get the idea from it.. And build your idea on it.. I think that is the best thing you can do..

kulky64 · Answer

I am not sure what an LM35 is and perhaps the LDR is a low dropout regulator. The LM35 is temperarue sensor with analog output and by LDR he probably means Light Dependent Resistor to automatically adjust the blinds according to light conditions in the room.

jw0752 · Answer

Hi kulky64, Of course you are right. I have worked with the LM35, 36, 37 series in the past but for some reason when I saw the number it didn't ring a bell. Also when I tried to search the number on Octopart it didn't come up. As far as the LDR is concerned you are probably right on that one too. Since I began on E-14 one of my pet peeves has been the use of unidentified acronyms and initialisms in posts. I began to collect them and identify them. To date I have a list numbering a little over 500 different XYZ, PDK, TTP, type codes that have been used. Here is a link to the post in case you are interested in looking at it. I just brought it up to date. https://www.element14.com/community/people/jw0752/blog/2014/10/03/acronyms-initialisms-abbreviations-and-variables John

AUTOMATED BLIND

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