Obtain RFID data via Bluetooth

[cal-pratt]

This issue is to discuss solutions for the task "Safety: Risk Mitigation" requiring that we:

Obtain RFID data via Bluetooth

Questions:

• What is distance for RFID underwater?
• What bluetooth devices could we use?
• What software can we use to read bluetooth in Java?
• Will the bluetooth device need to be mounted inside or outside the main enclosure?

[cal-pratt]

thoughts? @caw742 @FifoIronton @EasternEdgeRobotics/developers

[k-sutherland]

What I found from this is that we could get a signal between 30cm and a couple of meters underwater as a rough estimate. Between that and the aluminum in the enclosure, I think the bluetooth device will need to be outside the enclosure to maximize our transmission distance.

[stuckatmarine]

Hey All, get someone in the ROV program to run the Bluetooth situation by Vandervoort, one of the ROV instructors if there're are any issues. I think he did research on wireless subsea communications and the like. He knows a lot about mux systems too.

Duffett

On Thu, Nov 17, 2016 at 9:35 PM, Keith notifications@github.com wrote:

What I found from this is that we could get a signal between 30cm and a couple of meters underwater as a rough estimate. Between that and the aluminum in the enclosure, I think the bluetooth device will need to be outside the enclosure to maximize our transmission distance.

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[cal-pratt]

I think the bluetooth device will need to be outside the enclosure to maximize our transmission distance.

@krs158 lets verify this. If inside the can is possible it'll make electrical a lot easier. The less stuff we have leaving the can the better, however, if it can't be done then we'll with go with outside the enclosure. I think you should talk with the team about ordering in a Raspberry Pi 3 as it comes with built in Bluetooth. It's also good upgrade for the rasprime because it also has built in WIFI- meaning we can remote into it wirelessly :smile:

@stuckatmarine Sounds like a good place to start, it'd be nice to pick his brain. Mind sending him a quick email to get the ball rolling?

[k-sutherland]

@cal-pratt I did some research on the RFID transmitter MATE is using, as well as the capabilities of wireless signals through aluminum. I found that Mate is using a HC-05 bluetooth module that uses 2.4 GHz UHF radio waves. I also found a paper wireless signals through conductive materials. Using the skin depth formula, I found that the signal will be effectively diminished by 10 micrometers into the aluminum. Calvin brought up the idea of trying to receive the transmission through the enclosure lid, since the conductance is lower. The geometry works for the rov to be under the transmitter, so I'll look that up next.

[k-sutherland]

@cal-pratt I talked to nick and he said we are going to have to put the receiver outside the can due to the aluminum and the noise from inside the can.

[cal-pratt]

Mate is using a HC-05 bluetooth module

Good stuff! A quick search says they're only ~12$. We should get one up and running so we know what exactly what we're dealing with. Looks like there's some good tutorials online, but it'll probably still take a good bit of troubleshooting to get it up and running.

Calvin brought up the idea of trying to receive the transmission through the enclosure lid

Neat! I'd suggest covering the lid with with some foam blocks too (assuming the design is still to have the foam bordering the lid) and also testing it near the running electronics... Power sources have potential to interfere with bluetooth/ wifi so says the all knowing google https://support.apple.com/en-ca/HT201542

[k-sutherland]

The team brought up a good idea. Could we switch out the Pi 0 in the picam with a Pi 3? It would put the bluetooth receiver outside the can and closer to the transmitter without having to add extra external components. Would that work with our current setup? Also how often do we have to remake the cameras? The Pi 3 is significantly more expensive than the Pi 0, so it would make camera replacement more difficult.

[k-sutherland]

We decided we are going to buy 2 HC-05 bluetooth modules for testing. We can test different scenarios with them and it will help to have the transmitter that MATE says they will be using.

[FifoIronton]

Our major reason for switching to the Pi Zero is the desire to decrease the size of the camera module.

We could, if it seemed reasonable, pot a small Bluetooth receiver in the same epoxy as the Pi Zero. @cgregory52 , do you re-assert that size is the major concern of the camera module?

[k-sutherland]

@cal-pratt What are the buttons on topside? We noticed they have an input which seems really strange for buttons. What is the input used for?

[cal-pratt]

Buttons are the power profiles of the sliders. Short click loads a profile and long click saves the current values to the button.

In the future lets keep this thread focused on bluetooth; facebook chat or text is a better place for random questions!

[CalvinGregory]

Size of the camera enclosure should be minimized. Our camera placement in 2016 was severely limited by the bulky enclosure. Overall we will save more space on the vehicle with smaller cameras and a separate bluetooth unit.

[cal-pratt]

We had the HC-05 running tonight on the arduino mega! @bikobrido is starting work on the Java code so we can read to the HC-05 from the control software.

[hgm375]

https://github.com/Pi4J/pi4j/blob/master/pi4j-example/src/main/java/SerialExample.java

[cal-pratt]

FYI @ConnorWhalen https://help.github.com/articles/closing-issues-via-commit-messages/

You can close an issue by closing a PR is you write "This closes #X" or "This fixes #X" somewhere in the PR description.