Re: wireless temperature
As it is not crucial temperature reading for a nuclear power station you can use one-way transmission using “el-cheapo” 433MHz modules ..
Here are examples of such devices:
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Protocol can be very simple ..
The transmitter sends starting byte (quite often it is AAh, and it can be repeated for several times) followed by data string containing temperature reading, checksum and an end-of-transmission character, for example, CR (0Dh) ..
So it may look like the following:
AAh, 33h, 35h, 34h, CheckSUM, 0Dh
AAh – frame start
33h, 35h, 34h – ASCII coded 35.4 deg, you may, or may not use ASCII
ChecSUM – XOR of all characters up to this point ..
AAh xor 33h xor 35h xor 04h = 98h
As temperature sensor you can use the very popular LM335 which has sensitivity of ~10mV/degC
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Rgds,
IanP