Role of Beagle + Arduino +Tether


#1

Greating All,

May I know what is role of each : Arduino, Beagle and Tether.

I have noticed the Motors, sensors, etc controlled by arduino ! what about beagle ? what's role of it in Open ROV !

Also Tether, I have been told that the only use of tethers is sending data ! but I have noticed that if I do not connect the USB to my PC/Laptop the Board will not be turned on !

I would really appreciate if you explain these to me.

Warm Regards,

Salman


Beaglebone and Arduino
#2

The beaglebone is like the brain essentially, it is a stand alone computer which runs linux and runs all of the processes necessary to run the ROV. It has a processor and storage on the beaglebone including the webserver in which you connect to it using a web browser, and the video streaming service.

The arduino is the somatic nervous system (it turns the electrical impulses into physical outputs, the motors are akin to our muscles)

The tether is the method in which the video, and sensor data are sent to the controlling computer (laptop) and how your control inputs are sent to the ROV.


#3

Thank u very much Paul ^_^


#4

Salman:

In addition to sending data, the tether is also used to signal the ROV to turn on. The ROV senses +5V on the tether as a signal to turn itself on. That is why the ROV turns off when you disconnect the USB (5V) connection to the topside box.

-W


#5

Thank you Walt, that's the answer I was seeking for regarding the tether :)

Actually I am trying to make the OpenROV Autonomous ! my first step was defining pre-points for the ROV and I succeed ! for instance; if you press "D" the openrov will go forward for 5 second, left for 2 seconds and down for 2 seconds without using Forward + left + Ctrl button ! :P

my next step is to remove the tether bcuz at this stage I do not need to send or receive any info from / with my computer. I am trying to remove the tether and replace it with a Button ! if I turn on the button I want it to turn on. in Future I will use Zegbee or any good wireless module for transmitting/receiving data.

So, could pelase give me a hint how I can use a button instead of the Tether ? and eliminate the role of Tether to turn on the OPENROV !

Thanks,

Salman


#6

Salman:

Time for you to download the schematic for the controller board. You can find it as a PDF file on our Github site:

https://github.com/OpenROV/openrov-electronics

On Sheet 3 you will find the power switching circuitry. Note that you can bypass the tether-sensing circuitry by shorting across J12. So if you connect your switch to the J12 pads, it will then turn the ROV on and off.

-W


#7

Thank you so much Walt ^_^ I will let you know about the result !

What wireless module do u recommend me to use in future for transmitting/receiving the data ?

Yours,

Salman


#8

Walt,

Thanks for your answer and schematics are really helpful for a lot things.

But still for newcomers to electronic or users ( like myself) who are considering

to use other electronics ( Hummingboard,Gertboard ,TI Stellaris Sensorhub ) they are not clear enough

Sheet 6 should be enough to assess Humidity,Temperature sensor but

Sheet 7( BeagleBone Interface ) is really not clear.

The highest number I can see there is 20 so I would guess 26 GPIO on a Raspberry

Pi or Hummingboard should be enough.But if I look on Sheet 1 in can see in total

70 IO channel ( 54 digital / 16 Analog ) so its rather unclear how much are needed

to get ROV up and running.Maybe answers are within BeagleBone documentation

Gottfried


#9

Salman:

The role of sending and receiving data performed by the tether, is not a minor thing.

Wifi frequencies are not able to travel through water, hence it doesn't look to be any other cheap way for medium range data interchange, than the tether.

Are you planning to use anykind of long wave transmitters ? If that's the case ... May I know how do you plan to provide the required bandwidth ?

Regards and thanks


#10

Hey Ion,

Yeah that's what I am asking for :P

I know it is almost impossible to use current WIFI frequencies !

Actually I am not planning to use long wave transmitters ! At this stage I will use zigbee or other wireless module ! Here is my strategy: after certain time the ROV rises to the surface so the data could be transmitted/ received ! this scenario for me is applicable at this stage.

But again, it is just an idea and I am trying to brainstorm.

Thank you ^_^