LED stair lighting based on Arduino, Part 5

03 Jan

Well the testing did not went according to plan but I was expecting that. The main problem is because I was planning to use LEDs for lighting up the stairs, but because of festive season they have not arrived yet. So instead of 1W LEDs I got stuck with 10W halogens. 10W might not look alot but the current it needs is ~0.8Amps where as LED would be 0.08Amps. The maximum that ULN2803A can handle on collector is 0.5Amps. So when I’ve got everything connected the lights worked half way and then the chips went dead 🙁
The solution would be to replace ULN2803A with 2x ULN2064 quad Darlington arrays as they can handle much higher currents.
I’m putting this project on hold until I get the LEDs. Hopefully it won’t be long.

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8 Responses

  1. alan says:

    Do you suggest using ULN2803A’s instead of creating your own MOSFET circuit? An IC is good but you have to be careful on what you feed your circuit 😉

    • Andrius says:

      For driving LEDs ULN2803A is more than enough. It could drive LEDs of 5 Watts easely. IC is good as it is smaller package and 1 IC is cheaper than 8 transistors. I thought that I would not need to drive halogens but as LEDs have not arrived and I really wanted to try. The reulsut that I’ve got was dead IC. 🙂

  2. Stan says:

    Hi Andrius. Nice site!

    My wife recently told me we need sequential LED stair lighting as you are working on. I plan to use an Arduino and MM5451YN IC’s to drive the LEDS. Parts are coming in this week, should be fun. Would you share your code?



    • Andrius says:

      I will share it later. As the project is still not finished the code is in draft state also I’m not programmer myself so the code most likely will not be optimal but as long as it work I will be happy with it. 🙂

  3. Stan says:


    Any progress on the stair lighting? We’re stumbling in the dark without you! 🙂


    • Andrius says:

      Hi Stan,
      The project is not abandoned and is slowly moving farward. I just don’t have enough time for it. Hopefully will update in a week or two.

  4. Just commented on part 1… Didn’t see the updates until now.

    That is some serious power you are working with. Do you really need it? From what we have seen 10 watts of LED light is plenty to light an entire stairwell. You have the added benefit of being green.

    • Andrius says:

      I completely agree that 10 watts is enough. Just the installation I was working on had halogens. The idea is to save cost and look cool so it will be all LED based. I got myself a set of leds and hopefully will resume this project as soon as I have some time.

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