So this is my first forum post here as I am fairly new to Arduino. My project idea is for a sensor array of 10-15 arduinos (or similar micro controllers) buried beneath the sand on the beach recording soil moisture and temperature. I'm looking for help choosing what kind of wireless data transfer method would work best to send that data to a central receiver unit to log all of it to an sd card, or similar data storage method. Somethings I am worried about are the connectivity through sand as some sensors may need to be buried up to 10 ft deep. Any suggestions of what might work would be great!
Lets think about this a bit more. You can dig a hole 10 feet deep, but you can't dig a one foot deep trench for a cable?
Then think about measuring moisture and temperature in soil that has been disturbed by digging a hole and filling back in. Those measurements will not represent what is the undisturbed soil/sand.
If you must use wireless, may be you have to use an external antenna, which is kept at or near the surface. Or have the sensors in a separate container which goes to the bottom, and keep the Arduino + transmitter at the surface.
Wireless signals and 10 ft of sand (probably a lot more in the direction of the receiver!) doesn't sound like a working combination
to me.
Side question, plain curiousity: how do you plan to measure moisture? It's a notoriously tricky one that comes back on this forum time and again.
Paul_KD7HB:
Lets think about this a bit more. You can dig a hole 10 feet deep, but you can't dig a one foot deep trench for a cable?
If the "hole" is a bore hole just big enough to squeeze the project box through, and the trench is a couple hundred meters long (and must be deep enough to prevent shifting sands from destroying the cable - it's a beach after all), then it's not that hard to imagine you can dig a hole but not a trench, the cost of wiring notwithstanding.
Thanks for such a quick reply guys, and yes this maybe not a very good job for the arduino or wireless communication. The only reason I asked in here is because I am currently using an arduino Uno in combination with a Vegetronix moisture sensor and DS18B20 waterproof moisture sensor from adafruit. Currently I am only in the process of getting the code working then will transfer the project over to an Arduino Pro Mini for a final field ready prototype that can run on batteries.
Lets think about this a bit more. You can dig a hole 10 feet deep, but you can't dig a one foot deep trench for a cable?
Digging trenches is definitely not out of the question, as from what I am hearing it maybe the only viable solution, but I was just wanted to ask around and see if there was another way of sending the data that doesn't require a major disturbance of the beach ecology like digging long trenches would.