# Temperature distance measurement

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#### SimonTHK

##### Member
Transmitter: UWXL-24-PH

So I read about these sensors, they seem like very high quality and the cost is very high aswell. They transmit through 2,4 ghz and the receiver can be connected to pc with USB to get data on software that can log data and all good stuff. Also the receiver give an analog output signal so I can get a direct reading on a display I eventually make myself. Which is awesome.
So it seems good, but the costs are high.

You guys have any alternatives? I really am not gonna build it all myself (unless convinced too), cause it aint worth my effort (because I am slow developer). The transmitter can last 3 years on 1 lithium cell and IP68 with 500 meters distance. Those are great specs.

But before I go spend like 860 $I just want to ask you guys cause you allways have awesome ideas. Thank you in advance #### Pommie ##### Well-Known Member Most Helpful Member It would help if you told us what you are trying to do. Read temp every second/minute/hour/day? Do you need 500m? Can wifi be used as a bridge etc. Mike. #### SimonTHK ##### Member I need to read ocean water temperature in 1 meters dept. So it has to use wired sensor. I guess 200 meters range, but I like to add some range for precautions. I can do with 1 read each half hour at the least. I really would not want to use wifi, since my experience is that it generally needs more maintenance. Simon #### Pommie ##### Well-Known Member Most Helpful Member I assume dept. is depth. So the sensor is suspended in water via a wire and transmits the data via a surface transmitter? How big is this lithium battery that lasts 3 years? My initial thought was a wemos mini with wifi but even at 1 reading per hour it will only last 43 days on a CR2302 coin cell. You will need to use something like XBee pro to get the distance you require, however it would require programming and sealing in someway to be usable. The above is just me rambling as I've still no idea what you are trying to achieve. Mike. #### Josephuk ##### New Member I'm assuming you're creating a buoy to put somewhere in the ocean and then you'll have a receiver to pick up the transmissions from it somewhere on the shore? If so, the wireless transmission will be mostly line of sight and there's some very cheap transmitters and receivers that will do the job. I'm not aware of anything that is mostly prebuilt like your example of the UWXL-24-PH, however, I have quite a lot of experience with those cheap 433Mhz transmitters/receivers that you can buy from China on eBay for$1-2 - Most people who use them only want short range, but they are capable of longer range applications (some sources claim 1000m line of sight, but I think 600m is a better estimate). I can give you lots of tips for increasing the range if you're interested. Using a microcontroller, a waterproof wired DS18B20 temperature sensor, and one of those cheap transmitters could save you a large amount of money. The total cost of everything would likely be under $100 using this approach. It'll take much longer to get a working product and you'll have to do soldering/assembling and programming yourself, but it will definitely be cheaper. If you need it to be working and deployed quickly, maybe just use the UWXL-24-PH as you intended. #### Nigel Goodwin ##### Super Moderator Most Helpful Member Look at the HC-12, this is an RS232 to RF transceiver, is cheap and has a long range - particularly if you use an external aerial. As suggested above, a micro-controller and DS18B20 and you're sorted. Although I would suggest a solar panel to keep the batteries charged up. #### ronsimpson ##### Well-Known Member Most Helpful Member 433Mhz transmitters/receivers that you can buy from China on eBay for$1-2
The very low cost transmitters are built to be garage door openers, wireless door bells and such. If the door does not open you can keep pressing the button.
XBee pro to get the distance you require
There are "pro" and non-pro versions. Also 2.4ghz and 900mhz. I have used 900mhz at great distances.
Water resonates at 2.4ghz and will block the transmission. I live in a very dry place. 30% humidity is high for us. Twice a year we get a fog and the 2.4ghz transmitters will not work outside. For years the governments did not regulate 2.4ghz because they believed no one would use that band. It works indoors for WiFi but not well out doors. Your transmitter will be sitting on the water and the humidity will be approaching 100% I think anything at 2.4ghz will fail.

XBee and the like are smart. They are transceivers. They will transmit the data and then ask if the data was received with out errors. If errors they will re transmit the data.

Some of these modules can work in "mesh" mode.
Example: PC---100m---senser 1---sensor 2---sensor 3---sensor 4 ----sensor 5 ---sensor 6 ........
Data can go from PC to sensor 1, then 1 can talk to 2, 3 and some times 4 but no more.
Sensor 3 can reach 5 but not 6. Sensor 5 can talk to 7.
When data must go from 7 to the PC it must be re-transmitted down the long line. (many short jumps)

Last time I did this project we used 900mhz XBee modules. To keep the power down we used solar and the modules were asleep most of the time. Every hour all the modules woke up and talked to their neighbors. Data was send and received. Then every one went to sleep. The power was on for 20 seconds every hour. The receiver was on for 1 minute while the transmitter was on for a very short time.

#### SimonTHK

##### Member
Look at the HC-12, this is an RS232 to RF transceiver, is cheap and has a long range - particularly if you use an external aerial. As suggested above, a micro-controller and DS18B20 and you're sorted. Although I would suggest a solar panel to keep the batteries charged up.
I will try this out, and figure out what I will be measuring with later on if I can get the transceiver to work.

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