Blue tooth : 3.3V - 5V Serial how to

3.3 V 블루투스 연결하기 까다롭당

http://www.cellbots.com/how-to/handling-3-3v-to-5v-logic-level-conversion/

정석 ?

http://www.makingthings.com/documentation/how-to/scale-a-5v-signal-to-3.3v

구글에 무러봐 ?

http://www.google.co.kr/#hl=ko&newwindow=1&sclient=psy-ab&q=bluetooth+3.3V+5V+tx+rx&oq=bluetooth+3.3V+5V+tx+rx&aq=f&aqi=&aql=&gs_l=hp.3...476499.479773.4.480744.9.8.1.0.0.0.228.835.6j1j1.8.0...0.0.UPLB1OGCH6M&psj=1&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=f4f8389f214707a1&biw=1096&bih=870

Using the HC-05 Bluetooth RS232 Serial module for cheap wireless communication between your PC and Arduino

http://www.pial.net/post/Using-the-HC-05-Bluetooth-RS232-Serial-module-for-cheap-wireless-communication-with-your-uController.aspx

디바이스 마트에서 산거 : HC-05

● Bluetooth protocol:  Bluetooth Specification v2.0+EDR
● Frequency:  2.4GHz ISM band
● Modulation:  GFSK(Gaussian Frequency Shift Keying)
● Emission power:  ≤4dBm, Class 2
● Sensitivity:  ≤-84dBm at 0.1% BER
● Speed: Asynchronous:  2.1Mbps(Max) / 160 kbps, Synchronous: 1Mbps/1Mbps
● Security:  Authentication and encryption
● Profiles:  Bluetooth serial port
 
Power supply: +3.3VDC 50mA
Working temperature: -20 ~ +75 Centigrade
Dimension: 26.9mm x 13mm x 2.2 mm

아래 결선에서 TX / RX는 5V 출력측, UART_TXD/UART_RXD는 3.3V 출력측 (즉 ,3.3V 블루투스 출력)