My question is about protecting the analog input pins on an Arduino Mega from over voltage. I've seen many topics on this, and the zener diode solutions are typically outlined. These are good solutions.http://www.thebox.myzen.co.uk/Tutorial/Protection.htmlHowever, my question is this:If I am always getting my 5V reference from the Arduino 5V pins, would over voltage protection be of any benefit? For example, I may wish to generate a 0-5V voltage from a pot, by connecting on leg of the pot to 5V (from the arduino), GND, and have the wiper go to an analog input pin. In this case, it would seem that input protection on the analog pins would add no benefit. After all, if the 5V (which came from the Arduino board itself) surges, the Arduino itself is cooked.Yes, in that case no over voltage protection is needed nor makes sense to add it. Over voltage protection is useful for signals coming from external circuitry that you have no control over or are known to be of higher or lower (no negative voltages allowed) then the pins can handle.Also, I may want to connect an absolute encoder to an analog input. Again, the encoder needs to be hooked up to 5V. And if that 5V comes from the Arduino, transient suppressing circuitry or over voltage circuitry would seem redundant. You will have to provide a link to the specific encoder you are talking about, however that aside most encoders (incremental and absolute types) are digital in nature and do not provide a variable analog output voltage.LeftyAre my assumptions sound?
>>>> You will have to provide a link to the specific encoder you are talking about, however that aside most encoders (incremental and absolute types) are digital in nature and do not provide a variable analog output voltage.Lefty<<<<I've been using this encoder, w an analog voltage out:http://usdigital.com/products/encoders/absolute/rotary/shaft/MA3