I wanna build a shield to arduino where i can use multiple sensor while hogging a minimum of resources on the arduino. So therefore i bought some multiplexers(http://www.intersil.com/content/dam/Intersil/documents/isl8/isl84051-52-53%20.pdf) and p-mosfets(http://radioremont.com/datasheet/APM4953.pdf) and do a setup like this:
So can anyone verify this sketch and come with suggestion to make this solution “bulletproof”?
Thx for any replies:)
Hi, I think that you don't need to multiplex the V+ for the sensors, they can be powered up all the time, just multiplex the sensor outputs to the arduino analog input.
With your circuit, because you are switching the sensors on and off, you will have to wait each time you select a sensor a certain amount of time for that sensor to powerup and stabilize.
This will also drop your component count and number of arduino I/O resources.
According to my (old) book the 4051 has an ON resistance of 30 or 40 Ohms. You may need tot take that into account when reading analog values from your sensors.
Thx for your replies
Tom: I see your point, but in my case i gonna use a slow system with low sampling rate, so im prioritising to lower power consumption over time. And im also using some homemade soil sensors (DC through earth) so to power off the sensor is kind of vital for me I think.
Robin: Thx for pointing that out, i will have to do some hard core calibration