Hi all,

I am a self taught maker but I am starting a project with more LED's that i have ever worked with in one go so need some help.

I am creating an array of 52 5v LED's all with individual switches to be turned on each week (one led per week for a year) I am aware i need a resistor for each but cant figure out what the best resistor strength to use for each.

I will be using a 5v mini usb power supply plugged into the mains (UK), I have a super simple circuit to give a visual of what im talking about below.

Any advice on the ohm strength for the resistors would be a great help.

Thanks

 

If the LEDs are rated for 5V, then you won't need dropping resistors. Otherwise the type and intensity of the LEDs will govern the value of resistor.

If you could show what LED you are intending to use, then an appropriate resistor can be determined.

 

If you have to buy all the 50 switches, resistors, LEDs and wire, it may well be cheaper to have a Arduino driving a string of addressable LEDs.
https://randomnerdtutorials.com/guide-for-ws2812b-addressable-rgb-led-strip-with-arduino/
Then, under control of the Arduino program, any LED can be switched on and the brightness and color selected.
It could be worth a look to see if a change of design is the way to go.
Certainly, the construction will be a lot simpler.
The LEDs are available loose, on sticky backed strips and in wire looms.

 

Do you want the LEDs to be turned on automatically, one per week, or will they be switched manually? Automatically would probably be cheaper, because good quality manual switches could be one of the more expensive parts of the circuit.
Welcome to AAC!

 

Welcome to AAC.

To add to @dendad’s comment, if for some reason you wanted standard 5mm LED packages you can get APA102 LEDs that operate in the same way as the WS8212B versions but look like “normal” LEDs.

I have a question, though. Your brute force method is going to take a lot of wiring and a lot of switches. Even cheap switches (which are never really a good idea) will run you maybe $1.00 each. That’s a lot of money.

Could you explain what you are building. I understand it is based on the 52-week year but what problem is it solving?

 

In the spirit of pure speculation…

Were I going to do this I would use a minimal MCU and a rotary encoder. As you rotate the encoder it progressively lights the LEDs. I might even include a 2-digit 7-segment display of the week (LED) number so you didn’t have to count the lit LEDs which would be prone to error. I think I would also include a bit of non-volatile memory so the setting would survive power cycles.

If the switching bit has some special meaning, you could do the same thing but have the encoder select a week number and then have a separate switch to change the LED state.

You would also get the side effect of being able to make the LEDs light in sequence or otherwise animate if that provided any benefit, and since they are RGB they could have meaningful colors if that has value.

 

All electronics has some nice 12 volt 5mm diffused LEDs that look great @ 5 volts. Then you could use some DIP switches to turn them on.

There are some nice proto boards that will let you get at least 30 something of the LEDs in a straight line. (by offsetting them)

 

Then you could use some DIP switches to turn them on.

To me, one switch per week smells like user interaction with unskilled users. IOW, dip switches would be a problem.

ak

 

Once again, we have no idea what he is trying to accomplish, so we sit here speculating without information. A waste of everyone’s time.

Bob