I have set up the circuit below.
My problem is using the Arduino as the signal source. If I send a PWM signal (using analogWrite) it controls the brightness of all the LEDs, instead of controlling how many are turned on. If I replace the Arduino with a pot hooked on a 5v source, the chip behaves as it should. Is this a current issue?
Its all coming back to me now...Thanks Richard.
Some time ago I was working on the same LM3914 circuit and trying to make it work using PWM and a R/C circuit with my Arduino but it never quite worked right .
I finally opted for using a digital pot connected to 5V and feeding the wiper pin to the input of the LM3914. The digital pot was controlled by the Arduino. I had better control of which light would light up.
Just my 2 cents..
Seems like an odd way to control LEDs from an Arduino.
Reckon, what's with the digital to analogue to digital? Do you happen to have a drawer full of 3914s and no shift registers?
Graynomad and Richard Crowley; You guys are both right but in my own defence I did it as a way of experimenting and exploration of adapting a known circuit for automation using the Arduino.
In the final phase I did use a much more efficient method of controlling the LED's without using the LM's but the knowledge I got experimenting and understanding digital interfacing drove me to start thinking of new possibilities for newer projects.
I think that we all need to take baby steps before we can run
I think that we all need to take baby steps before we can run
True, I'm re-learning how to run after a decade away from any serious embedded electronics.
Got around to wiring the Low pass up and the values of 1K and .001uF didn't help. The circuit did work however when I went to 10K and 1uF. It might have something to do with my resistor values on Pin 7 and 8 of the chip, as mine are not exactly the same as the diagram.