6 replies to this topic

[aero]

Hello everyone,

just bought my first micro controller today. It's a Netduino Plus, and i decided to go with this one because i think it will be great for my future GPRS weather station project. I started a thread on the old Arduino forums but never really got the chance to get into it, because of college and work assignments. Now i finally have some time to tinker and i am really looking forward to going through the tutorials and building cool stuff. Can't wait for my package to arrive. Cheers!

[Mario Vernari]

Hello Aero. I think that your project could be done. I already tried to connect a GSM/GPRS modem to my Netduino Plus, and it worked without any particular problem. Bear in mind that it was just a trivial experiment, nothing deeper. The first thing you can do, is to describe a bit better what the system should do. It means decide a block diagram, assigning tasks for each block, and decide how to exchange data. Cheers

[aero]

Hello Mario, thanks for the reply. Basically i would like my weather station to collect the data from the sensors (wind speed and direction), and send it over GPRS/GSM network to a web page. I have no idea how netduino operates, nor how to break down these processes into block diagrams and steps, but i am willing and able to learn, and i can learn new things really fast, especially things that interest me. I am not in a hurry, just want to satisfy my curiosity and see how i do. These forums are a great place to start.

[Mario Vernari]

Oh, well...about the sensors, you should look for them. I'd collect several models, then I choose for the best ones. The remote site (where the sensors are placed) should use a Netduino, and a cellular modem. At this point you may choose whether it's better a Plus or the standard model. However, the Plus offers two interesting features that may be useful in this project: the TCP/IP and the SD (as data logger). The data exchange from the Netduino and the cellular modem is done via UART. Upon the modem model you may need a level converter, such as the RS232 protocol adapter: MAX232 chip/shield. PC/server side. Of course, you need another modem connected to the PC. You'd first choose in which way the data from modem to modem will have to flow. The simplest way, IMHO, is via SMS. It's pretty limited as carrier, but is really easy to implement, and you don't need any particular subscription from your phone provider. I know that many providers lock some features until you activate a particular subscription (paying more, of course!) The classical way to exchange data is using the modem "data-mode". This is the oldest way to transfer stream between modems, fully compatible even with the desktop modems of 20 years ago. It's a bit more complex than a simple SMS, but surely more reliable and...serious! The "ultimate" way to exchange data is via TCP/IP, if your modem supports the GPRS protocol. Unfortunately, I have no experience of using embedded devices GPRS-stacked. Finally, the PC server could be any feasible service/application, maybe just C# as well. It will act as receiver and/or queries for data, from one or even several remote points, such the Netduino will realize. Hope it helps. Cheers

[aero]

Mario thanks for the reply, you are very helpful. Actually i will be getting these components from Sparkfun: Weather meters: http://www.sparkfun.com/products/8942 Cellular Shield with SM5100B: http://www.sparkfun.com/products/9607 I am waiting for my Netduino Plus to arrive, and will order the rest of the components later. The weather meters are not currently in stock, and the cellular shield will be a gift for Christmas (i hope) I want to go with these components because i want it to be easy to replicate, if anyone would be interested in doing this project. I have an old Siemens MC60 mobile phone which i was planning to use but i think it is better to use the components/shields for the netduino, it is more standard and universal in my opinion. I like the SD card and TCP/IP capability of the Netduino Plus, and i hope i will be able to utilize it properly. I am a hang glider pilot and i would like to set up my station on a hill where we launch and fly. The hill is in a remote part of the country but has very good GSM/GPRS coverage so this first condition is met. Secondly, the station will be mounted on a pole surrounded by a fence, so no one can come and take it away. We need this station in order to get the real time wind speed and direction data. We don't want to waste time traveling to this remote location only to find out that the conditions have changed and have to turn around and go home. Now the fun part: basically, the data should flow from sensors to the SD card, and then from the SD card to my web database via GSM/GPRS Cellular Shield. I don't know if it is better for my web page to request the data from the remote netduino, or the netduino itself should send the data in a preset interval. Also i would need to sleep parts of the hardware between updates. I am planning to use the .NETMF and C# to achieve this. I also i need to figure out how to power the station, and need to enclose it in a weather proof housing. It will be cool to see the wind trend for this location over a longer period of time, i plan to monitor it for a year, and then move the station to another location or maybe build a new station with more capabilities. This should be fun. Cheers

[Mario Vernari]

Hmmm...bear in mind that most of the components are targeted for 0' to 70'C operating temperature. The SD has probably a more narrow range of temps. You know, 0'C is easy to match during winter. 70'C is harder to reach, unless you place the circuit directly exposed to the summer sun. In our labs we had several times (still now) problems of wide range temperature, but it's not easy to solve them. Cheers

[aero]

Thanks for the heads up. Hardware temperature range is for sure a thing to bear in mind, especially if intended for outdoor usage. I need to get into it, see what options do i have.