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I want to decorate my house with LEDs strips on each step of my stairs. I will buy LEDs strips with a 12V power supply.

I want that if I put my foot on the first step, the first LEDs strip turn on, and after every second, the next step turn on too until the last step. After 10 seconds on, the step must turn off.

To detect my foot, I'm thinking of using that kind of component : PIR (motion) sensor (product 189 on adafruit website). It act like a push button.

My first thought was to create two circuit loops. One to supply the LEDs strips with a transistor between each strip. And the second to control the transistor, so the turn on/off signal.

Thanks to your advices, I decided to use an Arduino to do the control loop.

I found this (http://www.zem.fr/decouverte-du-composant-74hc595-8-bit-shift-register/): Control loop with Arduino It's two 8-bit shift register, I have 16 steps on my stairs. With a simple bit of code, I successed in writing a Arduino code that push ten HIGH(1) bits from the right then sixteen LOW(0) bits. So I have what I want with the LEDs.

The question is : how to connect the 16 LEDs strips with my circuit (instead of the single led) ?

English is not my native language, I tried to do my best.

migrated from electronics.stackexchange.com Dec 13 '16 at 17:35

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  • The easiest way to get these sort of timing signals is to use and Audino or similar. Put the sensor in as an input, and each step as its own output. Would give you the flexibility of time control as well, so you can tune the effect to whatever you want. Would also easily allow for expansion with a sensor at the top of the stairs. – Puffafish Dec 6 '16 at 15:13
  • motion activated LED's are annoying. I prefer to leave them on always. Using Blue or Red for effects and mounted directly under handrail. You can drive from 12 to 14.2V to adjust brightness and feed with hidden phone wire. Les DEL activées par mouvement sont ennuyeuses. Je préfère les laisser toujours. Utilisation de bleu ou rouge pour les effets et monté directement sous la main courante. Vous pouvez conduire de 12 à 14.2V pour ajuster la luminosité et l'alimentation avec le fil téléphonique caché – Sunnyskyguy EE75 Dec 6 '16 at 15:34
  • You seriously want an Arduino for this. Software is easier and cheaper than hardware, and it's easier to change as you iterate (get experience, discover problems and find better ways). You could also do cool things with colors if you had 3 outputs per LED strip. – Harper Dec 7 '16 at 0:49
  • Theoretically, you've got enough I/O to not use a shift register? You could also use a "digital led strip" which have individually controllable LED's. But aside from that, your option seems good. – Paul Mar 15 '17 at 9:25
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Assuming your LED strips are essentially "always on" when they have power, you could replace the single LEDs in your diagram with transistors that sit between the power supply and the strip. Then, when your Arduino pin goes high, the transistor turns on the LED strip.

  • Yes, it is my first throught too, but I don't know which transistor I have to use. And Should I put the transistor before or after the LED strip ? – Adrien REUZEAU Dec 14 '16 at 9:42
  • Take a look at my answer to similar question so you can get an idea how to use the transistors to light the LED strip. – Chupo_cro Dec 14 '16 at 17:56

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