Bluetooth mod for your 7XX Roomba

[vic7767]

The SCI port is now located just under the right side of the carry handle on the top of the Roomba. Although a Rootooth could be used it will stick up vertically and is just not visually pleasant. For the brave of heart there is a mod that can be performed so that a BlueSM1RF can be installed inside the Roomba. Disassembly is required because the bottom of the PCA must be accessed to solder 4 wires to the bottom of the 7 pin mini din connector. 30 gauge insulated copper wire was used to connect to the mini din connector. Red to Vpwr + unregulated battery power pin 1 or 2. Blue to GND Roomba battery ground pin 6 or 7. White to TXD pin 4 and White to RXD pin 3. The 4 leads are extended over to an open area on the top right side of the Roomba case opposite the RF board. The BlueSM1RF operates from 3.3 to 5 volts dc so a LM7805 voltage regulator transistor is installed and is visible in the photo encased in black heat shrink just above the BlueSM1RF.

The photos are a GIF format so to see all three photos, click on the image.

[mfortuna]

Nice mod Ed. I wonder if you could have tapped into power on the board instead of adding a regulator. That's what I did on my Security Dawg project. The BAM required 5V so I picked it up right off the 5V supply.

Does the LM7805 get hot?

[vic7767]

I could have used a +5 supply connection on the PCA but I already had used this hardware on a previous application and everything was already wired together and all the connections needed were right there on the mini din. The BlueSM1RF does not draw much power so the LM7805 does not get very hot at all. I checked the transistor while the BlueSM1RF was transmitting charging data to a PC and the case was not hot after 30 minutes of transmitting.

[mfortuna]

In the early days of my security bot project I tried using a 7805 to power the wifi camera. It worked but got nice and toasty. Camera draws a bit more power than a bluetooth module!

I have a few 7805 footprint switchers I got from mouser. I plan on trying to replace the power supply board I have on my security dawg with one of these three pin switchers, just have not had a chance.

[pomonabill221]

In the early days of my security bot project I tried using a 7805 to power the wifi camera. It worked but got nice and toasty. Camera draws a bit more power than a bluetooth module!

I have a few 7805 footprint switchers I got from mouser. I plan on trying to replace the power supply board I have on my security dawg with one of these three pin switchers, just have not had a chance.

Hi Mike;
Do these switching regulators need any external components to operate like a choke or switching fet or shottky diode?
That sounds VERY interesting! SOOO much more efficient!

[mfortuna]

Nope they are drop ins for the 7805 footprint. All the external circuitry is built in. You can find them at mouser.

http://www.mouser.com/ProductDetail/Mur ... uTHH3%2fBw

[pomonabill221]

GREAT!!!
I detest the fact that when trying to get 5v, the problem of heat and efficiency is always present with linear regulators, and have never even thought of trying to find a switcher!
Thanks for the info and link!

[RobotMan_24]

On your mod, did you add any ability to turn the BlueSM1RF off / cut the 5v power to the device while its still running? Or do you just figure on turning off the power switch? I mean I guess it doesn't really matter too much - cool hack!

By the way, has anyone noticed any noticeable run-time difference when running with the bluetooth added? My phone dies much quicker, but it doesn't have wheels and a vacuum .

[vic7767]

Nope, the BlueSM1rf is on all the time just like the IR sensor on top of the front bumper. Very small amount of current is used and no noticeable loss of run time.

[SE_machine]

Nice. Too bad there isn't room inside a 570 (or is there? I haven't looked.) for this mod. My bluesmirf will be on its way in the morning, and it will be powered by an automotive USB adapter. These will go in the handle well under the faceplate. I'm having trouble uploading pictures, so I will upload a video to my YouTube channel once the smirf is installed.

http://www.youtube.com/user/MrTsolar?feature=guide