I am new to programming and am curious if the Arduino Uno is right for my project. The MC in my project will be required to read input from a keypad to turn on and off two 5V relays. The relays will have to be timed to open and close on specific time intervals that will be controlled by a potentiometer. I think the Uno will work just fine but want to make sure before purchasing. If anyone has any suggestions on a keypad, preferably Arduino, that would work well with the Uno that would be greatly appreciated as well.
The Uno can do all you specify but how accurate do you need the time intervals to be ? What sort of periods are we talking about (hours, minutes, seconds, less than a second ?) and how will the user know what the time interval is when turning the pot ? You are going to need some indication of the time set, perhaps an LCD or a series of LEDs. If the time intervals are fixed rather than being continuously variable then you could use pushbuttons to increment or decrement the time period in discrete steps. If you make the steps small enough you could make the period almost infinitely variable within a range.
Time intervals will only be changed for calibration purposes and will only need to be displayed during programming/calibration. Now that you mention it i suppose a potentiometer would not be necessary to adjust time intervals, I could program the keypad to adjust time intervals. Time intervals would range from approx a half second to a couple of minutes.
Pots certainly do not seem the best way to set time intervals unless they need to be continuously variable. Even with a display it would be tricky to use them to set the interval unless multi turn pots were used. Over intervals of between half a second and a couple of minutes the Arduino clock will be pretty accurate. How precise do the time intervals need to be ?
The relay controlled by the MC will be powering a pinch valve that takes .3 sec to close and .15 to open so a min time interval of approx .10 seconds would be ideal.