My question reference's a problem I'm having with my eletronic solution. I'm using a CI LM3915N-1 to build a bargraph circuit, where I need to turn on a few LED's depending the voltage that my CI receives. The problem is the arduino just write PWM and not analog voltage. So how can I solve this? how can I convert the PWM to a analog voltage?
Here is a image of the Bargraph circuit:
To understand better what I want, is to imagine that at Signal Source will be an arduino sending AC signal.
There are 3 options:
Put a low-pass filter on the PWM pin so that only the very low frequencies in the signal generated by the PWM, which will be at approximately the equivalent analog voltage, are allowed through.
Connect a separate DAC to the Arduino, either serial or parallel, in either integrated or discrete resistor ladder form.
Use an Arduino that has a DAC built-in, such as the Arduino Due.
If you are ok with limiting LED number to 8, you may have much simpler solution utilizing serial in parallel out register. 74HC595 will do the trick without any need for digital-analog-led conversion. You may chain shift registers to make longer led strips, that will certainly require additional ICs for each 8 bit group. As a bonus you will have individual control of every LED.
There are 12-bit registers also, although they may be harder to source. I'm not sure, maybe there are even longer one's somewhere.
