Hi all,
as in the title I would like to build ultrasonic tank level monitoring system with capability to report over GSM, beacuse of industrial environment. I have few tanks 6 and 15m tall. Tanks contain different liquid (oil, wastewater, base).

Initial idea was to use something like SonicSignalman unfortunately this solution have a lot of cons:
- 3m range - not enough for me and I cannot find similar product with bigger range
- to use it I have to register into provider infrastructure (server account) and depend on provider fees
- I'm in Poland, so to provider fees I have to add roaming

Because of that my idea is to build this kind of product myself .
What I need is ultrasonic sensor connected to my server through 3G modem.

Brief list of components for my prototype is:

1. Sensor - I think about cheap Chinese sensor with RS485 interface like CX-ULM-FS. Simpler/cheaper is better. It would be great to have sensor with Ex certificate. I found really hard to find prices and information for this hardware (most companies need contact with marketer and do not provide a lot of technical details about product). Any other suggestions for this kind of sensor ?
2. Single board computer - I assume that sensor with integrated GSM is hard to find (if impossible), thats whhy I need SBC as interface to outside world. Initially I choose Raspberry Pi. I'm a linux geek so I think that I can configure RPi as a interface between RS485/RS232 or other to GSM and configure the server in the network.
3. 3G modem - RPi wiki shows that Huwei modems works pretty well
4. other periferials - SD card, SIM card, wires, power supply, case, anything missing ?

I know basic electronics but I'm more firmware/os developer then electronic designer, so I would like to avoid PCB design and building system from scratch.

What is you opinion abut this system ?
Do you see cheaper/simpler approach to solve my problem ? Am I missing some options ?

P.S. This was my first post on this forum, so sorry for any confusion introduced.

In advance thanks for any opinions, answers, comments and critique.

 

On the surface your proposal looks very sound. Situations like this run smoother using pretested modules you plug together and just write the code.

I've never done GSM but I've seen a few. Mikroelectronica has one, and they wrote excellent manuals for the devices I did use of theirs.

DO email the manufacturer of the ultrasonic tank level monitor, answer all their questions and follow their direction. I used to make these things and they can be tricky: some want to shoot down thru air, some want to shoot up thru the liquid, and they cannot be interchanged. And all have a near dead zone, a minimum distance they cannot read.

Good luck and welcome to the forums!