user46990: Hello I am trying to send temperature data via bluetooth using the HC-06 module. Since TXD and RXD only allow 3.3V I have divided the circuit into two like the below image.
Is this method correct? or is there a better way to connect both two? 


Any help is appreciated.

user45674: As mentioned by chrisl, you cannot use HC-06 as a master device. Its firmware restricts it to behave only as a slave. So even if you are able to process the analog data from LM 35, you won't be able to send it using HC-06. It would be better if you go for HC-05 module and try the command AT+ROLE: x (x = 1 for master/0 for slave) to get the job done.
Coming to the 3v3 voltage constraint, I would suggest you to go for any Zener diode (in reverse biased mode) with 3.3V Reverse breakdown voltage. You can check the circuit for this here and order it from this link. If this is not possible anyhow, then you can also go for LM1117 3V3, but I would personally suggest you to go for zener diode. Comment back if you need any help in future.

46990: <p>Hello I am trying to send temperature data via bluetooth using the HC-06 module. Since TXD and RXD only allow 3.3V I have divided the circuit into two like the below image.
Is this method correct? or is there a better way to connect both two? </p>

<p><a href="https://i.stack.imgur.com/9BZl6.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/9BZl6.jpg" alt="enter image description here"></a></p>

<p><a href="https://i.stack.imgur.com/unQcu.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/unQcu.jpg" alt="enter image description here"></a></p>

<p>Any help is appreciated.</p>
 45674: <p>As mentioned by chrisl, you cannot use HC-06 as a <code>master</code> device. Its firmware restricts it to behave only as a slave. So even if you are able to process the analog data from <code>LM 35</code>, you won't be able to send it using <code>HC-06</code>. It would be better if you go for <code>HC-05</code> module and try the command <code>AT+ROLE: x</code> (x = 1 for master/0 for slave) to get the job done.</p>

<p>Coming to the 3v3 voltage constraint, I would suggest you to go for any Zener diode (in reverse biased mode) with <code>3.3V Reverse breakdown voltage</code>. You can check the circuit for this <a href="http://www.chegg.com/homework-help/questions-and-answers/33v-1n4728a-zener-used-33-v-voltage-regulator-5-v-source-shown--zener-diode-reverse-breakd-q19274856" rel="nofollow noreferrer">here</a> and order it from <a href="https://www.ebay.com/p/20-X-1N4728A-1n4728-Vishay-ZENER-Diode-3-3v-1w/1018498160" rel="nofollow noreferrer">this link</a>. If this is not possible anyhow, then you can also go for <code>LM1117 3V3</code>, but I would personally suggest you to go for zener diode. Comment back if you need any help in future.</p>
