How to build an autonomous remote wind station + camera

I'd like to build an autonomous remote wind station + camera that I can install near my favorite kitesurfing spot so that I can

  • Know in "real-time" both speed and direction of the wind
  • See what's going on there (it's mainly to know whether the spot is crowded)

As I have little knowledge of electrical engineering, I'm asking here for some help designing this remote station.

Here is what I've come up with

Objectives

  • Learn - I'm doing this to learn new things
  • Cheap - I do not exactly have a budget, but price will be an important factor
  • Autonomous - It has to work 365/24 without human intervention

Main subjects

  • Microcontroller
  • Communication
  • Power
  • Sensors (camera, wind speed, wind direction)

Microcontroller

It has to be programmable, so I can update/improve the behavior of the station if needed.

Any programming language will do - I'm a software engineer, that's what I do :wink:

I was thinking something like the Arduino, but I have no idea which model is the best fit for this station.


Communication

As the spot is 50km away from my home, I've found that the only communication protocol/network usable is GPRS/GSM (please, correct me if I'm wrong).

Sending the values read from the sensors (wind speed + direction) can easily fit in a SMS.
I've found a SMS gateway that let me receive SMS for free. It appears to be exactly what I need.

But sending an image (even a 320x240) every minutes (or less) requires a data connection. Indeed, transferring 320x240 = 76 800 pixels will take about 590 SMS (at 140 bytes per SMS minus 10 bytes for the overhead).

Again, there's way too much choice here. Do I need a dualband, a quadband or a 3G/GPRS shield?

Note: I like the 3G/GPRS one as I can easily attach a 7 € camera. But 140 € is kind of expensive.
Note II: I am aware that using GPRS/GSM/3G requires a SIM card with unlimited SMS and/or data. But in France, they are pretty cheap (~15€ per month)


Power

Solar powered appears to be the best (only) choice.

This solar module looks like what I need but I have no idea if that is too much or not enough?

  • Is there any way it can be cheaper?
  • Have you got any advice regarding the installation of the solar panel in order to maximize its efficiency?
  • Is there any warnings regarding the rain?

Sensors

Camera
Apart from the cheap camera (which goes with the 3G/GPRS shield), there are plenty of cameras available.

Again, way too much choice here. I don't even know where to begin... What do I have to consider?

Wind Speed + Direction
I've found these weather meters and even a tutorial (in French) with some help regarding how to connect the sensors to the board and read both values.

There is also some code for Arduino.

This appears to be the easiest part (at least for me) of the station.

Reading values from the Wind Speed sensor is as easy as incrementing a counter and reading values from the Wind Direction sensor is as easy as doing a modulo.


Some other questions

  • How do I prevent the station from being struck by a lightning?
  • What is the best material to use for the support? Wood? Steel?
  • What kind of enclosure can I use to prevent the station to heat too much?

Thanks

Using SMS messages to send data sounds a bit nasty and would need a plan that gives you a huge number of texts. If you can get a plan that allows it, using a handset that supports 3G/data would be far easier, faster and probably cheaper.

Regarding the enclosure, can you mount it securely? Assuming this is something you'd be building for yourself, I suggest you style it like a conventional weather station i.e. a white box with slatted sides. This will keep it cool and also dispel any curiosity about what it does or what it's for. Are you actually entitled to install private equipment in that area?

Given that beaches are places where people tend to get undressed, I'd be very cautious about installing anything that could possibly be construed as spying on them. In my mind that means putting it far enough away that there is no possibility of it showing detailed pictures of people on the beach. This also means that it's probably far enough away that the people on the beach will not notice or be concerned about it.

But sending an image (even a 320x240) every minutes

I guess every 10 minutes is more than often enough.

Do I need a dualband, a quadband or a 3G/GPRS shield?

That depends on the location where you plan to install the device. What kind of signal do you receive there? Is there 3G covering? A quadband usually doesn't make sense in Europe as only two frequencies in the GSM band are used here (to my knowledge).

Solar powered appears to be the best (only) choice.

The more often you wanna have your pictures at home, the more power you need. Expect that the GSM module needs more power than a feasibly sized solar panel. So you have to add a battery to save the power during the rest of the time. Your setup won't send data if there's no sunlight, are you prepared for that (probably not a problem for a kite area)?

Apart from the cheap camera (which goes with the 3G/GPRS shield), there are plenty of cameras available.

Only the two most expensive ones are feasible for the use with the Arduino because they support the delivery of the picture over UART.

This appears to be the easiest part (at least for me) of the station.

I guess this is correct :).

How do I prevent the station from being struck by a lightning?

Don't install it on a metal pile. Try to stay lower then surrounding "better targets".

What is the best material to use for the support? Wood? Steel?

Plastic. Steel is holding your radio signals back and wood is not durable enough.

What kind of enclosure can I use to prevent the station to heat too much?

Why should it heat that much? If you mount it below the solar panel it shouldn't get too much sunlight and the self-heating should not be that high (you don't have enough power for that).

Thanks for you answers @PeterH

PeterH:
Given that beaches are places where people tend to get undressed, I'd be very cautious about installing anything that could possibly be construed as spying on them. In my mind that means putting it far enough away that there is no possibility of it showing detailed pictures of people on the beach. This also means that it's probably far enough away that the people on the beach will not notice or be concerned about it.

The spot I plan to install my station is only used for kitesurfing.
Kitesurfers usually are used to see wind vane/anemometers as wind is their main concern :wink:

Thanks for your answers @pylon

pylon:
I guess every 10 minutes is more than often enough.

I'm thinking more and more about killing the camera feature and only going with the wind sensors...

pylon:
That depends on the location where you plan to install the device. What kind of signal do you receive there? Is there 3G covering? A quadband usually doesn't make sense in Europe as only two frequencies in the GSM band are used here (to my knowledge).

Yes, there is 3g covering.

pylon:
The more often you wanna have your pictures at home, the more power you need. Expect that the GSM module needs more power than a feasibly sized solar panel.
So you have to add a battery to save the power during the rest of the time.

Care to elaborate more?

If this is being installed at a public beach:
a) how are you going to prevent your installation being stolen?
b) won't you need permission to install this station?

Pete

Care to elaborate more?

The usual 3W solar panels provides you with 1-2W if not exactly in frontal sun beam. As this isn't enough to power a GSM module, the Arduino and some sensors, it's necessary to have a GSM module that you can power down when not used. You can also let your Arduino sleep while not being used to save the solar power to the battery during the 9 minutes the station is between two transmits. This way you can consume more power during the transmits and your probably able to transmit data even if there's no direct sun light. If you need a resolution of more than the 10 minutes measure every minute but send it only every 10 minutes because the main power is consumed to establish the connection not to effectively send the data.