I'm using hc 05 bluetooth with arduino, my PC have BT dongle, I wonder how far I could take my HC 05 away from my PC, and they could still talk to each other?
BTW my HC 05 has 6 pin, GND, 3.3V, 5.0V TX, RX,KEY. shoud I use 3.3V or 5.0V?
thanks
They claim 10m. I have worked 15m line of sight but I wouldn't bet on it. One framed wall cuts it to about 5m and one sheet of foil insulation can kill it stone dead.
If your module is a JY-MCU it has its own level circuitry in the power supply. A voltage divider on the Arduino Tx is good practice but I have not done it myself and have never had a problem.
thank you.
another question, how could I use bluetooth programming arduino?
I don't think so, and I don't see the point in it anyway. A suitably programmed Arduino can be controlled by bluetooth, which may be what you really want anyway. You will find plenty of examples of that here.
Note that I forgot to point out that there are other types of Bluetooth modules that have greater range, but I don't know anything about them.
I think BT is just like COM connector. it should be possible to use the BT COM port to download code to arduino.
Bluetooth operates on a COM port as a serial device. You presupposing that downloading code via the serial port is normal practice. You need to learn up about serial ports, shared ports, and FDTI, but it would probably be more constructive to work out why you would want to do this in the first place.
my arduino device is placed at a hard to reach location. when I found a bug, I need update arduino code without take my device apart.
Well you are going to have to do a lot more to programme it remotely, but I imagine it would be quite easy to test different subroutines in response to bluetooth commands. Besides, bluetooth is really more of a convenience than something uniquely essential. A long USB cable might do the same job.
thank you Nick. I think I saw something about wireless download code for arduino on youtube before. would you tell why it's not possible to do so?
I didn't say it's impossible, I just don't think it's possible to do it the way you imply. You will soon find that you can't just send the stuff over Bluetooth. That's for sending data. I think you have three choices.
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Come up with some way to configure the serial port to think it is connected to the IDE by FTDI
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provide a hardware device on the serial port to do that.
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provide a hardware device that receives the bluetooth and IS plugged into Arduino's USB port, which case Arduino wouldn't know the difference and would be quite happy.
I'm afraid I have no idea how you would do any of this, nor have I any idea about how you would connect the Arduino IDE to bluetooth on the PC in order to send the stuff. Maybe it's all in the YouTube clip you saw.
Now I'm kind of know what you mean. you mean arduino IDE only support FTDI (usb-to-serial) interface. and not support serial directly. I thought IDE support real serial port, because in IDE tool/serial list, it list all COM port. I don't know if anybody tried to use real COM port to program arduino. I mean disconnect usb cable, apply power to power jack, connect GND, TX(TTL level ),RX(TTL level ) to arduino GND, RX, TX. then program arduino.
xianwu:
Now I'm kind of know what you mean. you mean arduino IDE only support FTDI (usb-to-serial) interface. and not support serial directly.
That's as I understand it, LoL. I don't know what you saw on YouTube, but it's a lot trickier than it first appears to be!