Heat sensor project

Hello everybody, and sorry for my possible horrible English... (France powaaa) So, here is my project : a temperature sensor for a pool.

I want to read the temperature 3 or 4 times a day, during 3 weeks. So I have two big questions :

1- is it possible running the arduino during 3 weeks without it burns out ? If yes, how can I supply it [u]outdoor[/u] during 3 weeks ? (Will a 9V battery be enough ?) if not, is there a solution to automatically turn it on and off at choosed hours ?

2- I have to use 2 arrays (1 for water temperature and 1 for ambient temperature), with 3 values per day, there are 3*21*2=126 values (168 with 4 values per day). Can the arduino uno memory stock all this ? Furthermore, I saw that I might use libraries to read temperature with the sensors, the question is : will I have enough memory ?

One thing more, I don't have any idea how to get arduino values and transfer them on a PC, is it just possible ?

Thanks a lot, A lost french

Bonjour PastaLover

An Arduino cannot run on any battery (certainly not a 9v one) for 3 weeks without some (quite advanced) power management, which just complicates your (first?) project. You need to run a 5-12v power supply to it. Surely there is this possibility near a (swimming?) pool. If not, this must be resolved first.

To read the temperature data is very straightforward and I recommend using the DS18B20 'One Wire' sensors as you can have several all controlled with just two wires. See my YouTube video #28 which covers this in some detail.

To log the data you will need an SD card, also very simple. You can then read the SD card in your PC without problems. See my YouTube video #22 on how to do this.

But first you must describe the 'pool' - swimming pool or frog pool? Power or no power?

URL for my videos is in the footer of this post. Please let us know about the power though!

Thanks for your fast answer,

Sure, the first problem is supplying. When you said “a 5-12v power supply”, is it a sector supplying ? (Wired to a house plug with a 220v/12v converter ? In France, electricity is 220-230).

Secondly, are you sure there isn’t anyway to get the data from the arduino intern memory ? If y might save the price of a specific arduino sd adaptator…

About the pool, it’s a swimming pool (in French, the translation “piscine” is only about swimming pools, there is another word for frog pools) with sodium chloride (Na+Cl-, I don’t remember what is the word), I2 (diiode in French) and some chlorine (just a little…). pH is close to 7, so I think the sensor will resist…

Thanks another time for your answer

Edit : I changed my pseudo meanwhile

Google for "extension cord protector". They come in various sizes and lengths. This may keep people from tripping over the sensor wires if you are actually testing pool water and not water being circulated by a pump.

Paul

loma2001:
Sure, the first problem is supplying. When you said “a 5-12v power supply”, is it a sector supplying ? (Wired to a house plug with a 220v/12v converter ? In France, electricity is 220-230).

The most common method is a 220/9v adaptor. It is called a wall wart.

Secondly, are you sure there isn’t anyway to get the data from the arduino intern memory ? If y might save the price of a specific arduino sd adaptator…

Since you have so few records, it would be quite practical to store them in memory, but the problems are reliability and convenience. An SD card only costs about $2, and fixes both.

sodium chloride (Na+Cl-, I don’t remember what is the word), I2 (diiode in French).

In this context, it is just called salt(!)

OK, as it is a swimming pool, with potential for a power supply (house mains) nearby, then apart from the tripping hazard caused by the cable (!) this project is good to go. The other respondents above seem to think so too.

EDIT: if these links don't work just search eBay and Banggood.com (the EU site).

You need a 9v - 12v adapter from your house (or swimming pool pump station) to the arduino board (assuming you are using an Arduino UNO [clone] which has a jack adapter). If you do not use this board and choose something like an Arduino Nano then you must do some soldering to put the input voltage into the Vin pin. But this too is an added complication for this project - stick to a V3 UNO [clone] which you can buy from the Far East for about $5 / €4. A bit more from the EU. See this one (EU)

Waterproof sensors of the DS18B20 type are also readily available and are impervious to swimming pool water. Search on eBay and you will find ones for just £1 / €1.50 like this or slightly more expensive if you buy it within the EU. Buying in the EU ensures quick delivery, like this one from Bangood's EU warehouse.

Then you can add another DS18B20 for the air temperature (either of the same waterproof type of just naked).

Definitely use an SD card for logging - my video #22 explains why it is so easy and more reliable than trying to write to EEPROM on the Arduino. Especially as you want to read the data on a PC.

Well, until you have decided what to do, and bought some equipment there's not much more to say except that this project is ideal as a first project, easy to do but approach it step-by-step because you are unfamiliar with the Arduino.

Good luck and post back further questions. Or, bonne chance et vous parler bientôt.

Thanks everybody for your answers !!

So, I need :

-a 220/9v adaptator to supply the arduino (it's an uno, yes) (maybe I'll use an extension cord, but it isn't important)

-a sd shield to connect with the board (with a sd card, surely...)

-two sensors for temperature (the first objective ...)

About the code,what is the top value for delay() function ? 2^32>number of milliseconds in 6 or 8 hours so I can use this fonction without crash my program ?

Nick_Pyner: In this context, it is just called salt(!)

Sure, I didn't remember the English word...

I don't know what the number is but it is good for several days, so you won't have a problem with a few hours. A couple of DS18B20s would be fine for this. They can be had in weatherproof package and 5m cable. A tutorial is at http://www.hacktronics.com/Tutorials/arduino-1-wire-tutorial.html

loma2001: About the code,what is the top value for delay() function ? 2^32>number of milliseconds in 6 or 8 hours so I can use this fonction without crash my program ?

You can use the millis() function for 49 days before it resets (just subtract the new value from the old one and calculate the difference)!