How to make a large LED chase effect?
I am looking to make a Xmas jumper with an LED chase effect to mimmic the snow falling. I am having difficulties in deciding which is the best way to do this.
Essentially Think of having 8 strings of 8 LED's (to make it simple) and each string will have its own chase effect running. I want these to be independent of one another, I.E. I don't want a constant LED line running down the jumper.
Now I have thought of two ways of doing this via Arduino:-
1) Simple Method - Using the ATMEGA328 to run each string of 8, providing its own running time and speed.
2) Difficult Method - Use a grid where one ATMEGA328 can run a 8x8 matrix. This would require some transistors at each row and column and fancy code to produce the right effect.
Disadvantages of 1&2
1) Lots of wiring, 8 ATMEGA chips and power supplies
2) Unsure if this is possible, obviously I can switch quickly but to the eye would this even be visible. For example if I wanted to power column A and row 1 and simultaneously power column D and row 5... would this power said LED's and also column A row 5 and column D row 1, all at the same time?
Any help would be greatly appreciated. If I have overlooked any other methods, please feel free to mention them.
Thanks
Mo
Comments
5 years ago
If you like to solder, here are some fun chase circuits.
1] Uses the fact that the 4017 can advance on a rise or fall clock giving you a smooth transition 18 LED chase.
2] Is a trivial light house ckt.
3] Bill shows how a long LED string is wired.
5 years ago
Perfect, thanks very much guys, going to check all these out tonight!
5 years ago
By far the easiest method: Use NeoPixels !
Answer 5 years ago
+1
Why build what already exists, just tell NeoPixals what you want to see in Basic or 'C' very easy and you can easily run 8 independent strips from a single uP.
Wiring is extremely simple..
Answer 5 years ago
New 'Ible about NeoPixel Xmas trees coming soon.....
5 years ago
Just some good old TTL logic is all one would need to make it happen! a simple decade counter like the 4017 CMOS device and 555 timer will do the job, and you can make a bunch of completly separate modules. I did a similar thing using a string of 8 white LEDs on a breadboard, and used a 555 timer for a clock signal into a 74LS164 shift register, and fed the output of the last LED through a transistor inverting amp, back into the serial data in. This creates a really cool effect!
5 years ago
You can use shift registers like the 74HC595, example:
https://www.arduino.cc/en/Tutorial/ShiftOut
Combine with Charlieplexing and you have an led dot matrix driver.
5 years ago
I would use a ring counter with a delay between the strings of LEDs.
5 years ago
Check out CHARLIEPLEXING - it's a way to run many LEDs from few outputs.