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by perfo
Sun Sep 13, 2015 1:17 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: interface with digital calipers
Replies: 52
Views: 13196

Re: interface with digital calipers

If it were easy to splice two inexpensive devices to work the same as one expensive one, the manufacturer would have probably noticed. Yep I would totally agree but still I wonder what the differences are. If you look at these pics https://www.flickr.com/photos/50241702@N04/5227386500/ The track ap...
by perfo
Sun Sep 13, 2015 1:06 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: interface with digital calipers
Replies: 52
Views: 13196

Re: interface with digital calipers

Thanks for the reply. You've hit two problems on the head though... "A good tutorial with the Arduino"- I haven't found one with enough details yet "It should be easy to convert" - I agree it may indeed be easy for someone but not for me :) The hardware is obviously very different between RPI and Ar...
by perfo
Sat Sep 12, 2015 10:25 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: interface with digital calipers
Replies: 52
Views: 13196

interface with digital calipers

Hello, I've done a fair bit of reading and researching on this but haven't really come up with a definitive answer. I have a small lathe and would like to put DRO's on it but they are expensive. On the old google and in the walls of this forum I have read about folks connecting and reading data from...
by perfo
Sat Sep 12, 2015 9:04 pm
Forum: Advanced users
Topic: Limits of Multithreading
Replies: 10
Views: 7302

Re: Limits of Multithreading

I know it's nearly a year old but how did you get on with this project ? I want to do something similar. I'm my tinkering even though the PI is capable of these things (especially the new speedy version) I prefer to hand off real world real time things to other devices. So I'd be using the pi to int...
by perfo
Mon Aug 10, 2015 7:13 pm
Forum: Automation, sensing and robotics
Topic: A bluetooth chessboard
Replies: 12
Views: 6703

Re: A bluetooth chessboard

Ah yes I'm on hols and 8 pints down but it does makes sense (to me). Perfect then except only being able to Id the piece from memory only.
by perfo
Mon Aug 10, 2015 6:37 pm
Forum: Automation, sensing and robotics
Topic: A bluetooth chessboard
Replies: 12
Views: 6703

Re: A bluetooth chessboard

A normal keyboard (scanner) with. Diodes at the crossing points, I'll have to think about that one (not suggesting any one is wrong of course).
by perfo
Mon Aug 10, 2015 12:38 pm
Forum: Automation, sensing and robotics
Topic: A bluetooth chessboard
Replies: 12
Views: 6703

Re: A bluetooth chessboard

I think that would be the problem of using a keyboard scanner in that you have 32 keys pressed at the same time...
by perfo
Mon Aug 10, 2015 11:24 am
Forum: Automation, sensing and robotics
Topic: Tracking movement of game pieces on a board
Replies: 14
Views: 6546

Re: Tracking movement of game pieces on a board

what about rfid's a small rfid in each chess piece then a coil under each square. The coils would have to be connected to then sampled so some sort of multiplexing would be needed or maybe have 64 inputs and try and read them in software. This isn't a highly thought out idea of mine :) but it would ...
by perfo
Wed Feb 11, 2015 3:24 pm
Forum: Automation, sensing and robotics
Topic: Control GPIO with game controller over LAN
Replies: 1
Views: 623

Control GPIO with game controller over LAN

Hello, all. I'm building a ROV and have a few stumbling blocks I could do with a little assistance with please. I have my RPI set up as a web server. I have a web page with buttons on so I can turn GPIO on and off over the internet. What I want to be able to do is to control the speed of a motor ove...
by perfo
Sat Jan 24, 2015 2:09 pm
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

Thanks for the link. There's some real interesting stuff in there it clarifys the ethernet encoding thing. I can see me using that site a fair bit. I may even get around to building the oscillascope one day.
by perfo
Fri Jan 23, 2015 7:49 pm
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

I should start another thread really as this has gone way out of the hdmi to laser area. My latest idea is something completely different. As I can't have a tether to the cameras I'm thinking of a drone instead. I didn't go up the path of using a ROV to mount the camera on due to it needing a skille...
by perfo
Wed Jan 21, 2015 1:26 pm
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

ha yep... The carrier may be a simple sine wave or something but I agree there could be nothing else simple about it... I shall continue my search for knowledge on it...
by perfo
Wed Jan 21, 2015 9:54 am
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

Good idea, I have done a little search to see if anyone has done exactly that..but can't seem to find any. Does this mean it's not easy to do ? I thought (as you did) it will be a simple carrier sent to a transducer and if so it should be able to be modulated. They do appear to be a little sensitive...
by perfo
Tue Jan 20, 2015 11:23 am
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

Interesting read, I shall probably have to read it several times before fully understanding it :) It does seem to prove (not theoretically suggest) that 10's cm are possible with 2.4ghz... So all I need to do it to come up with a wave guide to get that signal to the surface and I'm on to a winner. I...
by perfo
Tue Jan 20, 2015 10:05 am
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

PIGraham, if you scroll down in the doc I sent you'll see they also do calculations for 2.4Ghz and state for average fresh water the theoretical penetration depth is just over 16cm which maybe enough for me... I haven't got access to many 5Ghz gear but borrowed some and then threw them in a lake :) ...
by perfo
Mon Jan 19, 2015 8:56 pm
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

Some interesting stuff, I’ve been digging in to the physics of it all just to try and get my noggin around what the problems with Wifi and frequency are ( I didn’t manage). However after a bit of research I came across a paper calculating the penetration depth of electromagnetic waves in water. If u...
by perfo
Sat Jan 17, 2015 12:13 pm
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

I've been chatting to a fellow that can supply a leaky feeder for 30m . Again it would have have to be tested to see if the coax can survive in 30m depth due to it containing air voids in it's structure. But the losses over 30m of Leaky feeder antennae isn't fantastic so as long as I can aim the Yag...
by perfo
Sat Jan 17, 2015 10:49 am
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

The 15 cm mentioned in the paper is also in salt water which I'm guessing is a worse medium than fresh water it does look promising. There are a minimum of four places in the pit on each side where i'd need to see the latches. So if I were to have AP's under water then I'd need eight per pit , unles...
by perfo
Fri Jan 16, 2015 5:12 pm
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

just trolling the eBay I can get a Yagi 25dbi antennae (item 251370446239) for £5.00 I would have to mount this in a pipe or something to keep it in air I guess.. I can also get a 2000mW USB WiFi adapter for £9 (item 151460450701) .... Could any clever fellow assist me in working out what difference...
by perfo
Fri Jan 16, 2015 4:59 pm
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

As I'm back to WiFi I'm going to try another experiment. I'm going to put a bit of cable inside a pipe (as explained before) this cable wouldn't be connected to anything it will simply be floating (electrically speaking. Putting it inside a pipe will keep it dry and thus not earthed by the water. A ...
by perfo
Fri Jan 16, 2015 4:53 pm
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

Just one last suggestion for now. Forget about the Pi and find something that is capable of transmitting a video signal underwater. Like this: http://www.japantrendshop.com/rc-12-wireless-mini-waterproof-video-camera-p-225.html I've just had the reply about this item and unfortunately they state it...
by perfo
Thu Jan 15, 2015 9:24 pm
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

Since you know a tether will be broken eventually you can account for that by using a sacrificial tether. Something as simple as a waterproof RJ45 connector on the camera and a 30m ethernet patch lead. Every time the patch lead gets torn or chopped, clip another one in. It simply becomes a consumab...
by perfo
Thu Jan 15, 2015 9:21 pm
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

I think it will be easier to devise a reliable latch & sensor to confirm the latch is good than to feed images wirelessly from 30m underwater. Does the beam travel with the crane? Is this one beam that is lowered in every case? Can't you run cable down from the beam to the hook? Sounds like a job f...
by perfo
Thu Jan 15, 2015 9:10 pm
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

Just a thought: what you are interested in isn't the camera output but whether or not the latches have engaged. Could you use an optical recognition pattern to identify the latch engagement, then send you a single jpg as confirmation? Yes indeed that could be an option..a smart idea ,, thanks.. As ...
by perfo
Thu Jan 15, 2015 9:08 pm
Forum: Other projects
Topic: HDMI to laser
Replies: 49
Views: 7123

Re: HDMI to laser

Couple of quick remarks: 1) You may find Ronja, optical point-to-point data link interesting, see http://ronja.twibright.com/ for details. 2) LEDs can be pulsed fairly fast (FWHM down to ~10ns) with reasonable efforts, the power in single pulses is not very high. As you seem to have the possibility...

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