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Topic: How to get 28 leds fade in a sequence and maintain voltage when power is divided (Read 394 times) previous topic - next topic

Smush

Im working on a 1: 25 model that consist of over 50 leds, about46 of them smd leds, and 4 are 3mm leds all being powered by a 5v breakout board and the Arduino The problem I'm having is getting 28 smd leds to fade in a sequence. I can get 3 on and fade just fine but when I add more, the leds starts losing voltage.

Here's the setup on the circuit board:

.5v USB power source to 5v breakout board
.Positive to 5v regulator input to 470uf compasitor to 100ohm resistor to Arduino 5v pin
.Ground from Adruino to breadboard
.Regulator to ground, positive output from regulator to 470uf compacitor to positive on breadboard.
.pins 9,10,11, programmed for fading sequence ( imitating rotating effect on old police lamps)
.pin 9 to transistor (same for pins 10 and 11)
.9, 10, and 11's transistors to ground
. Three 100uf compacitor to leds
.Leds back to transistors completing the circuit


PaulRB

Your description of the circuit is indecipherable, sorry. English is not a good language for describing circuits. Please draw us a schematic. Hand-drawn would be fine. If you want to use Fritzing, please use the schematic view, not the breadboard view.

Grumpy_Mike

Quote
pin 9 to transistor (same for pins 10 and 11)
What no base resistors?
Also no mention of resistors limiting the current through the LEDs, you need them.

Are you using PWM to drive the LEDs? On a Uno only 6 pins are capable of PWM output using the incorrect named analogWrite function.

I think we need to see your code as well. Use the IDE's copy for forum and paste the results directly into your reply.

PaulRB


Grumpy_Mike

I wonder if the OP will reply to this thread.
Well three posts so far and not a single answer to any of them.

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