Raspberry PI based ROV

[Moki]

Right, got it.

So the closer to the target, less power to the engines.

There is a way to manual control the engine power, in the program [keys '[' and ']'] or digital back buttons on the controller.

For an automated power controle, we need a way to measure our position or distance. Dont you think?

[perfo]

Slightly more cunning than that but basically that's it. PId controllers are use on things like deck guns on war ships or larger cranes etc etc.. To get the thing moving you need full power but leaving full power on until near the target and you will over shoot, reducing the power slowly until you hit target and you will also generally over shot.. By programming in the inertia , weight etc then the controller will knock the power off or very near so including inertia etc it still ends up on target. How much power you start with and how it decays depends on the difference between the start position and desired..

Hmm I could waffle all day so if you are interested then the wiki page will do a lot better explanation than me
http://en.wikipedia.org/wiki/PID_controller

A quick question on your set up:- I think I've got the basics of Node js sorted but I'm struggling with the html bit.. Ie I'm not sure how to make a front end page the way I wont it with buttons and scales etc... did you use some sort of graphics program to help you or did you do it all in code ? I'm struggling with this bit, yours is close to what I want and I suppose I don't really need to change it but I also want to make it my own and do a different front end if possible....

[Moki]

The PID controller sounds like a nice thing, like i said before i'll add it to the wishlist.
So many basic things are not even working to my satisfaction, it will have to wait a bit.

The Moki ROV software was never intended to be released or kickstarted. Its just a hobby project.
(But job offers or money for professional suppport are welcome ofcourse )

Anyways....

The webbrowser screen uses HTML5 / Canvas, to draw the things we need. I tried to look for things that were the be found on the internet. They either cost (lots of) money or wasn't what i was looking for. So i made them myself.
With my current skill set, i am sure anything is possible to add.

And a different frontend is possible, you just have to create it. You could start with my frontend and change little things or go wild and (do it better than i did, and) replace the whole thing. Skills i needed are: HTML5, Canvas, nodejs, socket.io and gamepad.

[perfo]

Did you dive in and start banging out HTML script ? or use some sort of graphical website builder ?
Please don't misunderstand me when I say I want to do my own front end it's not that I'm implying yours need any changes. It's just I would feel like a cheat to use someone else s. I can achieve everything I need with a VBA form front end and a database on the PI but that's not learning something new and I've never got in to HTML coding so feel this may be my opportunity...
If I get completely fed up or out of my depth I can always buy a complete kit for something like $900 but then again doing something like that wouldn't be in my nature and fills me with dread...
Ta Matey

[Moki]

No worries... not offended in any way, just trying to understand your reasons.

All is scripted from a text-editor (vi)

And all, in one way or the other... was googled (is that cheating, too?)
And transformed into what it is today, ofcourse being a Linux engineer did help.

One of the reasons i put the source online, was to help people move quicker to driving a ROV, instead of learning all kinds of programming skills. The list of skills needed to create a ROV, is long enough as it is.

Feel free to do whatever you like I had lots of fun, creating this software.. hope you have too!

[perfo]

Thanks...

[Moki]

Right, made some progress with the ESC programming... tried to connect the ESC switches to the free relay.
Didn't do what i was expecting, like resetting the ESC's to default.

Guess i have to find a way to power off/on the ESC's remote on an other way.

BTW, if you have tried this software... and the ESC didnt do anything.. you were right... the action was "remmed out"
So yes to console logging, no to send a pwm request to the ESC's

Update and it should be fixed

( Score for today, one burned/fried ESC )

[perfo]

Oppps you cooked your ESC ?? How did you do that ?
I'm hoping to use a servo driver card..like the spark fun one and control it with I2C. I had thought these ESC pretty much look after them selves as long as you don't put on too much supply voltage... Maybe I'll have to be more careful.

[Moki]

My ROV v1, uses Bilgepumps (1100)... They love volts.
So far, i used small and much to low amps ESC's. (30A, dx.com)

When programming, sometimes the software crashes. So the moters keep running full power.
And before i found the part that created the crash... The ESC run hot... Smoke and smelting plastic result in melting ESC... Scratch an ESC. (I really should make a kill switch)

The local RC shop sells great ESC for about €80, currently i am using the Hobbyking ESC (car / 45a)
Which cost less than €10... But take forever to arrive (do these come by container ship?)
So they aint perfect... but better than the dx ones, but at the price... I can still order 30 more and it still would be cheaper.

And it still baffles me, that when i power on, 1 ESC.. The others also start to become active.
The 5v line to the servo board is already cut. So they should not receive power if they are not connected to 12v. (The 5v red servo line is cut, so that the BEC of the ESC doesnt send power to the servoboard. In the RC his would be a way to power the RC reciever, but the servoboard is powered externally... And 4 ESC,s sending 5v to the servoboard is sure to create a smoking servoboard.

[perfo]

I'm afraid I'm still waiting for mine (brush less three phase though) so have very little experience (none) with ESC. Maybe if you post a diagram of how your system is set up, someone with a bit more experience will spot what's going on.. It sounds like a back feed some how..Expensive hobby if you burn too many of them $80..gasp.
I'm wondering if the ESC are water proof enough to fix them out side the hull and thus help keep then cool. From the pictures they look pretty well potted so maybe OK for fresh water ...