Thermo.Hygro 433MHz Cable Free Transmitter sensor

Hello My outdoor sensor that transmit to a receiver at my home finally die on me. It is a Thermo.Hygro 433MHz Cable Free. That is what's on the front of it a picture is below. I want to replace it with another one But i thought maybe i could make this into a project using parts i have around here. I do have what frequency it uses by looking up the FCC ID Which is Here. What you see on the image is packing tape because i lost the clip to it that mounted on the side of my place :( .

So i need help on this project which should i do in order to make one? I do have a 433mhz transmitters and receivers i got form ebay would it work i do not know they are standard cheap transmitters and receivers. They can be found Here.

I do have a dht22 temperature and humidity sensor i can use. Also make it portable and able to save battery i been working on in my other project i can use on this one.

But there are a few things i been worried or wondering about. First is the frequency going to match up with the receiver that i have i don't know If it will know the Dht22 or the transmitter i have. So a lot of unknowns is why I need the help.

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Transmission on the right RF frequency is one item, you can check whether your available senders are accepted by your receiver.

Another item is the data format, sent by the old sensor and expected by the home station. This can be any binary stream, and you're almost lost without a second (working) sensor, from which the data format could be determined. Also the transmission mode has to be determined, does the sensor send at regular intervals, or only when asked for by the base station?

The simplest solution were finding out the failing part of the outdoor station, and if it's the humidity sensor or the sender, replace it by some commonly available one.

Hello DrDiettrich i was thinking of replacing the whole transmitter part because i went thought the caps and lcd as well as transmitter, The lcd only shows half of a screen. Funny thing is i have another device for something totally different that uses the same screen and i swamp them and the LCD works so it is not the LCD. Which only thing that remains is the Micro processor has failed. So replacing the part is not happening. I could buy another one. So one thing that remains can make something or buy a new one.

That is an Oregon Scientific remote sensor, and they have all been decoded/reverse engineered. There are three different RF protocols, depending on the sensor type.

Transmitting the signal is a bit easier than decoding, but there are web sites that show you how to do both. Some links:

https://buildthings.wordpress.com/arduino-intercepting-oregon-scientific-weather-station-anemometer-wind-vane-temperature-humidity-barometer-rain-gauge-data/

http://www.shuhy.com/esi/osv3_dock_sensor.htm This project sends temperature and wave height using the OSV3 protocol, using Arduino.

Thank you i will look more into it and the links. This will help me big time.

josephchrzempiec: I do have a 433mhz transmitters and receivers i got form ebay would it work i do not know they are standard cheap transmitters and receivers. They can be found Here.

Not sure on what basis you are using the TX\RX but for unlicensed ISM band use the allocated band is 915Mhz (Region 2).

Is the use of 433Mhz permitted for such devices in the US ?

I live in the USA we use 315mhz 433mhz and i have seen 915mhz devices here.

It really depends on what you are going to receive the temperature data on. If you are using an Arduino as the receiver , its easy to build your own temperature sensor that looks like an Oregon Sensor as much of the OSv3 protocol has been reverse engineered. However if you want to use an Oregon Console as the receiver then it gets a lot harder as not all the data fields in the OSv3 protocol are understood and Oregon uses a modified form of manchester coding thats not easy to generate.

I have looked over everything and I'm convinced that I'm not able to make my own transmitter to work on the receiver that came with my outdoor temperature sensor. So I took the second way out. To build my own transmitter and receiver to work out door. Using the same case and same temperature sensor as well as humidity sensor that came in the old broken device. Hope fully i can get at least that to work. Not sure how to make a DHT22 sensor weather proof or made for outdoors lol

As I'm going to build this into now a full project and use some of the parts to build a new transmitter and receiver with LCD on it. I was looking at the broken transmitter side with the micro little thermistor temperature sensor and there is a little humidity sensor as well in there. But what I'm wondering is if i can reuse them would it be feesable to do so?

josephchrzempiec: I live in the USA we use 315mhz 433mhz and i have seen 915mhz devices here.

I guesse

josephchrzempiec: I live in the USA we use 315mhz 433mhz and i have seen 915mhz devices here.

I guessed that those 3 are in use in the US, but which of them is permitted ?

all 3 are in the usa at leat 80% of out devices are using 315 433 and 915 mhz.

I guessed that those 3 are in use in the US, but which of them is permitted ?

They all are, under Part 15 of the FCC rules, which govern low power unlicensed transmitters.

Commercial, 434 MHz Oregon Scientific TH132N remote temperature sensors have FCC ID NMTTHN132N-01. The label states "This device complies with Part 15 of the FCC rules."

jremington: They all are, under Part 15 of the FCC rules, which govern low power unlicensed transmitters.

Thanks, I have shipepd a few tracker boards across to the US, I figured they were using 433Mhz.

Do the FCC publish the conversion that should be used to translate the power limits specified such as;

(125/3) x f(MHz) - (21250/3) ┬ÁV/m @ 3 m

Into plain old mW that is used most devices data sheets ?

Do the FCC publish the conversion that should be used to translate the power limits

No, because it depends so strongly on the antenna.