I've been thinking for a long time to create a low cost and reliable water level monitor project for my main well wich is constantly mutating and pretty difficult to measure considerning the depth and location. Initially i figured out this was the easiest way: Water Level Sensor | ysi.com
but it seems also the most expensive... so I decided I'm ready to learn new approaches, I'm thinking to use this ones: SparkFun Pressure Sensor Breakout - MS5803-14BA - SEN-12909 - SparkFun Electronics
The difficult part is that for the project to be worth and reliable as I said, I'll need two of them connected in a SPI slave daisy chain together with the arduino official ethernet shield mounted ontop of the arduino UNO or MEGA 2560 (wich I already own), such that I'll be able to log and see the calculated results from the two sensors remotely. WHAT DO YOU THINK? IS THIS EVEN POSSIBLE DUE TO DIFFERENT CLOCKS AND ARDUINO LIMITED RESOURCES? VALID ALTERNATIVES WELCOMED!
rapbando:
The difficult part is that for the project to be worth and reliable as I said, I'll need two of them connected in a SPI slave daisy chain together
I don't understand exactly what you are concerned with.
SPI is intended to facilitate multiple slave devices.
What do you mean by "daisy chain"? Usually that means that A sends to B and B sends to C. But I imagine you want two pressure sensors both connected to one Arduino? Please clarify. A simple diagram would be very useful.
Daisy chaining of SPI devices works only if each sensor outputs a single byte, as in the case of 8 bit shift registers. For longer data packages, as with your sensors, the devices must be addressed separately.
The I2C interfaces allows/requires daisy chaining, but due to the limited address selection only 2 such sensors can be used on the same bus - unless you use CSB to enable just one of multiple sensors. Or you add an I2C multiplexer, for up to 8 separate I2C buses.
As the sensor is designed for in-fluid (dived) operation, the board and all electrical contacts have to be isolated and water-proof, up to the maximum pressure (water depth).