IRobot and Bluetooth Adapter

[CSJeff98]

I have continued working on my IRobot Bluetooth project.

I have used the HC-06 to create a Bluetooth adapter for the IRobot connecting to the mini din port.

My Labview code outputs through UART to a Comm port, but my computer does not have Bluetooth built in.

If I were to get a HC-05 and connect it to the computers Comm port, could I then talk to the robot over Bluetooth. If so what exactly would I need to get to continue this project.

[RTSLVU · Accepted solution]

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@CSJeff98 wrote:

I have continued working on my IRobot Bluetooth project.

I have used the HC-06 to create a Bluetooth adapter for the IRobot connecting to the mini din port.

My Labview code outputs through UART to a Comm port, but my computer does not have Bluetooth built in.

If I were to get a HC-05 and connect it to the computers Comm port, could I then talk to the robot over Bluetooth. If so what exactly would I need to get to continue this project.

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I would suggest, as I suggested before, an FTDI USB to 3.3V logic serial adaptor like this USB-RS232-WE-1800-BT_3.3  

If your computer has an RS-232 serial com port on it and you want to use that. then you will need to build a level shifter using a chip like a MAX3232 and four capacitors. https://pdfserv.maximintegrated.com/en/ds/MAX3222-MAX3241.pdf

[CSJeff98]

And from there it would be as simple as wiring the HC-05 to the USB-RS232 and plugging in the USB part to the computer?

[RTSLVU]

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@CSJeff98 wrote:

And from there it would be as simple as wiring the HC-05 to the USB-RS232 and plugging in the USB part to the computer?

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As long as you get the 3.3 volt version.

But with a slight caveat. I have found that these (HC-05 and 06) are 3.3 volt devices buy they are commonly placed a a little carrier PCB for use with an Arduino. The problem is they put a voltage regulator on the carrier to operate off a 5V supply like the Arduino, but with 3.3 volt data lines. That makes it a pain in the ass because you have to level shift the data to 3.3 volts when using a 5 volt Arduino.

When using a 3.3 volt Arduino the HC-05 will still run but with a reduced range.

What I did was jumper across the 5 volt regulator  it so it can be directly powered from 3.3 volts so it got it's full range.

Also do yourself a favor and buy an actual FTDI adaptor. 

Don't fall for some generic adaptor on Amazon for $5, chances are it will have a counterfeit Prolific chipset in it and will cause all kinds of headaches.

[CSJeff98]

Would you recommend any other Bluetooth adapters to avoid doing this or is it simply unavoidable?

[RTSLVU]

Just get a bare HC-05 module that is not on a carrier PCB made to plug in to a breadboard like the ones designed use with an Arduino.

What kind of HC-06 did you use on the I-Robot? Is the I-Robot 5V or 3.3V logic?

The ones on the carrier PCB will work fine on 5 volts without level shifting the data lines, but not forever.

I am guessing this is just one way comunications, from your computer to the I-robot but nothing coming back?

You could just get the 5 volt FTDI cable so you can directly power the HC-05, from 5 volts. The level shifting from 5V to 3.3 is a simple diode (1N4148) with it's cathode connected to the 5V serial data and a pull up resistor on the anode to 3.3 volts. The anode also connects to the Rx on the HC-05.