Go Down

Topic: Which Arduino for Weather Console Replacement? (Read 242 times) previous topic - next topic

Willy45

I would like to know if the following is feasible and what version of Arduino  and accessories I would need to accomplish this.

I am looking to replace my current 14 year old weather console. The console is obsolete and the interface for downloading data to a PC failed a couple of years ago.
The sensors all appear to be in good working order and in excellent locations. They are hardwired and I see no need to goto a wireless system with the grief of power supply and interference.
I feel that I could repair the each of the existing sensors or replace them if necessary,

Sensors:
1. Wind Direction - linear pot 0-20k (10k = South, 180°, desired output degrees xxx and 16 cardinal points as text i.e. NNE
2. Wind Speed - switch closure, desired output xxx mph, possibly switch knots in software record average and peakGust
3. Rain - magnetic reed switch, desired output Today xx.xx inches YTD xx.xx
4. Outside Temperature - variable resistance, -50 to 140°F desired output outside xxx first x can be a minus sign High xxx Low xxx
5. Inside Temperature - same as outside
Possible additions:
1. Barometer xx.xx inch
2. Humidity xxx %

Would like to have LCD display (16X4, 20X4, 40X4 as req'd) on arduino console (size and shape TBD)
Would like to have a real time clock on board for time and date stamp.
Would like to have onboard storage (SD or Micro SD card) for several days data that can be download to PC periodically as a .csv file. Data stored at 5 or 10 minute interval
Want this to be a low power (wall wart and battery backup) standalone unit. l. This should be easy after I measure the current draw. My objective is battery backup for approximately 24hrs. This is why I am leaning toward Arduino because I think its power requirements are rather low.
There would be some calculations on board and readable on the LCD i.e. Wind Speed High, Rain total for day, Temp Hi/Lo.
This is to be a stand-alone system with the only connection to the PC for download of the .csv file and possibly to update the onboard clock.
I am only using the data for my own use, I have no desire to connect the system to the internet weather sites.

As for me, I am retired, I have very little experience with software programming but am a fast learner. My programming consisted of some Basic programs and modification of programs on a TRS-80 computer in the 80's'. It looks like there is a lot of Arduino programming info available.
My hope was that somebody had already done this or something similar but my searches have been unsuccessful.
My initial guess is an Arduino Mega 2560. Too much, not enough, out to lunch?
Any help or advice would be appreciated.

Thanks
Willy

Pauly

Hi,
I made my own weather station.
Maybe this will give you some ideas.
http://electricprojects.wordpress.com/2014/01/05/jeenodes-weather/
You may be able to get away with an Uno.
If you can get a "backpack" for the LCD that can cut down on the number of pins needed.
Good luck.

wildbill

An Uno has plenty of processing power for what you need, but depending on the interface for the components you attach (LCD, RTC, barometer, humidity) you may find that you're short of pins - a Mega may be easier.

You may have an issue with the length of wire runs from your sensors impacting your readings - you'll be analogReading for temps and wind direction - how far from the arduino will they be?

If you want an SD card, maybe consider an ethernet shield (which has one) and then the arduino can also send weather data to the PC directly rather than having to remember to take the SD card over there periodically.

I'd suggest you start small - work on one sensor at a time and figure out how to read it. An Uno might be nice for this task - cheaper to replace if you destroy it and useful for subsequent projects if you don't.

One thing to design up front though is the display; you'll need the rendering of your data elements figured out so you can decide how large an LCD you need.

PaulRB

#3
Apr 19, 2014, 12:19 am Last Edit: Apr 19, 2014, 12:26 am by PaulRB Reason: 1
Hi willy45,

I too am in the process of building a weather station.

Uno will be fine, or Arduino mini/micro/nano, which will fit on a breadboard, which will be a convenient way to prototype your solution.

For barometer, I would recommend a bmp180 on a breakout board. For humidity, an sht21 (again, on a breakout board). For the real time clock, a ds3231 (guess what, also on a breakout board, which will also have a backup battery). All 3 of those use what's called the i2c bus to transfer data to the Arduino, so only 2 pins needed for all 3 of those devices. In addition, all 3 devices have built-in temperature sensors, so you probably won't need the existing indoor sensor.



http://www.ebay.co.uk/itm/1PC-BMP180-Digital-Barometric-Pressure-Sensor-Board-Module-For-Arduino-/121171624986?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item1c3664441a

http://www.ebay.co.uk/itm/1pc-Standard-SHT21-Digital-Temperature-And-Humidity-Sensor-Module-New-/301153432842?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item461e24b50a


http://www.ebay.co.uk/itm/Tiny-DS3231-AT24C32-I2C-Module-Precision-Real-Time-Clock-Module-For-Arduino-/370976656302?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item565fee8bae

Paul

Willy45


Pauly, Wildbill and PaulRB,

Thank you for your ideas and comments.

Pauly,
If I have trouble with my wired system, I will look into the jeenodes.

wildbill,
I will go with the Mega for the project but, I may also get a Uno for some of the testing, and I can always think of something else to do with it later.
I had not thought of the wire runs. The shortest is about 30 ft. and the longest is about 75 ft. and they run in 3 different directions. I was very particular in locating each sensor. The cable looks like regular 4-wire telephone cable. I looked at my information on the original equipment and it says "RC low-pass filter on each signal line" so I'll open it up and see what method they used. There is a small junction box that ties the three telephone-like lines to an 8-conductor cable that  feeds the console. Since I have not had any sporadic readings in about 14 yrs. I would guess that their method is Ok. But, that's not saying it won't be a problem with Arduino.
I certainly agree with your break it into pieces and start small approach.
My next step before placing a parts order is to decide on my LCD layout, I am thinking  of probably a 4X20 LCD with current conditions and a switch to cover daily highs and lows.
I will include the ethernet shield in my orders but, that will probably be the last part to be programmed.
Pretty agressive for a guy who knows very little about programming!

Paul,
I like the specs on the barometer and humidity sensors, I will use them for my project. Interestingly, I had already selected the same clock module.

Again thank you for your thoughts and advice.
Willy45

Go Up