Possible GSM project

[boriz]

Here’s the Spec.

A self contained, solar powered, interrogable weather station. A single unit, easy to reproduce and easy to mount up a pole. It measures the wind speed+direction, the light conditions and the humidity/rain conditions.

At any time, a remote user can send a ‘request’ text to this unit and a moment later will receive an SMS containing the current conditions at the site, the average recent conditions and the trends.

This is specifically for the use of an RC airplane flying club.

Any advice as to exactly what hardware would be required, generally how to proceed, and specifically how to do it on the cheap?

 

[hippy]

Should be easy enough in principle. Choose a phone or a GSM modem which will output an incoming SMS or a ring signal ( maybe even detect DTMF tones ), collate the data, sends an SMS back. The rest is all 'weather station' and hardware.

For cheap, start with a PICAXE and a mobile phone with an RS232 data cable. I'd probably choose an X2 for the HSERIAL capabilities though it could possibly be done with SERIN and qualifiers.

 

[MPep]

Hi Boriz,

The other thing to make sure of is that the GSM modem is capable of sending text data via SMS, not PDU protocol only.
This will make implementation MUCH easier.

No, I don't have any hardware in mind, but they are out there.

MPep.

 

[Simmicht]

Here is a great piece of hardware to start with

The weather station I will leave up to you or others ... but i will add a pic of my solar powered wind monitor as a teaser, it also has a 28X2 and XBEE...
You can see the data here ...http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=IQLDFORE4&wuSelect=PWS
and on pachube http://www.pachube.com/feeds/3037.


I have a PixAce28X2 doing a very similar thing in my car tracker. The Telit GE865 does both PDU and SMS. I bought a $30 Vodafone sim here in Brisbane Australia, and this allows me to SMS the car and find out the data from the GPS. handy when son 2.0 forgets to "phone home" when borrowing my car. I have done the basic SMS handling, I need to complete the FWD function so carrier generated SMS (like when you top up) get sent to me and not back to the carrier.

Latest enhancement, I now have the GPRS context working, this allows me to send a ULR to my home web server (every 250m) and now I can get a live track of the position of my car. I digress. Below are the parts from SparkFun.
So go have a look at these parts, download the datasheets and price it up.
I will be happy to proved code, or maybe post snippets here. I want to submit the whole project to Siliconchip soon so I don't want to give away all the code, but I will be will to help.

'Uses GE865 Quad cell module
http://www.sparkfun.com/commerce/product_info.php?products_id=9297

'U.Fl antenna to SMA
http://www.sparkfun.com/commerce/product_info.php?products_id=9145

'Quad Band Celluar antenna
http://www.sparkfun.com/commerce/product_info.php?products_id=290

'SIM card holder
http://www.sparkfun.com/commerce/product_info.php?products_id=573

'Voltage reg-High Current LT1528
http://www.sparkfun.com/commerce/product_info.php?products_id=311

'Uses Venus GPS
http://www.littlebirdelectronics.com/products/Venus-GPS-with-SMA-Connector.html
http://www.sparkfun.com/commerce/product_info.php?products_id=9133

'magnetic based GPS Antenna
http://www.sparkfun.com/commerce/product_info.php?products_id=464


'Uses a MAA7620 accelerometer
http://www.sparkfun.com/commerce/product_info.php?products_id=252


'Uses OpenLog to record information to a microSD card. Information in a csv format
http://www.sparkfun.com/commerce/product_info.php?products_id=9530
'Documentation for OpenLog
http://wiki.github.com/nseidle/OpenLog/command-set

Here is a picture of the PCB, I will make the latest available on BatcPCB.com.
The cost is about $32 AUD to have made and $10 to P&p and about 1 month to wait ...

 

[MPep]

The Telit GE865 does both PDU and SMS

Please note that PDU is a data encapsulation method for packaging the data for SMS transmission.
Some GSM modems allow direct ASCII input, and can then transmit this, i.e. they do the encapsulation 'on-board'.

 

[Simmicht]

SMS v PDU

Yep the TELIT does both types SMS messages, I issue a

    HSerOut 0, ("AT+CMGF=1",cr,lf)

this does as the manual suggests,

AT+CMGF - Message Format
Set command selects the format of messages used with send, list, read and write commands.
Parameter:
<mode>
0 - PDU mode, as defined in GSM 3.40 and GSM 3.41 (factory default)
1 - text mode

The basic 'send a SMS' goes like this...

SendSMS:
HSerOut 0, ("AT+CMGS=0406333333",cr,lf)
TimeOut=4000:Gosub ParseScratchPad
HSerOut 0, ("Test Message text goes here",cr,lf)
TimeOut=4000:Gosub ParseScratchPad
HSerOut 0, (26)                'When message composed, tell Telit to send
TimeOut=4000:Gosub ParseScratchPad

RETURN

The basic usage of the TELIT is simple (maybe from my perspective now after hours of doing this)
1. Turn On TELIT, to do this the pin connected to the TELIT.ON is held low for one second then back to an input.
2. Wait till the TELIT.PWR goes high.
3. Issue signal strength requests AT+CSQ and wait till the response is between 0 and 99.
4. Issue these setup commands, waiting for the "OK" to come back from the TELIT, the default baud is 9600.
AT+CGMR
AT+CGMM
ATE0
AT+CMEE=2
AT&K=0
AT+ICF=3
AT+CPIN?
AT+CMGF=1

 

[Simmicht]

maybe too much

Sorry , I think I missed the cheap part of the spec. The TELIT is about $100 AUD and you add more for all the other parts.
I assume this is so a member can check out the conditions before the go there, other wise why not use a piece of granddad's magical weather string. You can get a length of the special string and and locate it on a pole.
If it is wet, then it is raining.
If it is dry then it is sunny.
If it is still then there is no wind.
If it is moving about then there is slight wind.
If it is about about 90 degrees to the pole then there is a strong wind.
If the string and pole are missing then there is a hurricane.