Picaxe video capture

I'm wondering if picaxes are getting close to realising a cost effective video capture system independent of a PC. An example would be a roving robot, or remote security applications where data is then sent some distance via wireless links.

There are many cheap systems that interface with a PC using a video capture card or directly via USB webcams and I have built these and they work, but the PC always needs to be on and this means it needs a power supply, and then if the location is remote it needs a shed and solar panels and batteries and inverters and the whole proposition gets out of hand.

Brainstorming:

1) USB webcams. Very cheap but interfacing to the USB becomes expensive. A cheap laptop is probably less expensive than palm type computers, but this still rules out the small robotic solution and the remote access solution.

2) Use the new 28X1 part and interface with the new serial SPI USB drive interface. Pair this with a USB pen drive camera. Capture the data then forward it on using the standard picaxe wireless or infrared solutions. Even possibly analyse it in simple ways - eg pick some pixels and compare with rgb values to detect colours.

I am looking forward to all the new parts - I gather they are still in Australian customs but will be released soon.

I wonder if there are any other cheap video interface solutions out there?

I have seen a number of people are using this
<A href='http://www.robot-electronics.co.uk/shop/Camerax39s2081.htm' Target=_Blank>External Web Link</a>

This may allow you to do something with captured data.

Not cheap I know, but direct accurate video sampling is out of PICAXE zone.
I've been looking at video sampling for tracking (in a similar way as the above limk) and its quite daunting.

There may be other similar/cheaper products out there, so I'll leave others to Google.

The problem with any interface to USB devices is that the processor has to be a a USB Host and understand the above-USB protocol of the device attached. USB-to-serial allows a PICAXE to become a USB Slave but doesn't give it any capability of becoming a USB Host.

Connecting PICAXE to USB webcams is only likely to become feasible when something like the Viniculum devices appear which act as hosts and capture devices and as a bridge to allow the captured information to be easily accessed in a non-USB way.

Hmm - maybe USB is a bit complex. I've been looking at SD memory and I found this SD memory interface board <A href='http://www.hobbyengineering.com/H1613.html' Target=_Blank>External Web Link</a> - the datasheet explains the interface which works via RS232. Sort of a DOS type language which returns a command prompt &gt; after each command. Would work for datalogging as well.

Digital cameras store files to SD memory - either pictures or movies. A hack would be needed to switch the SD card from the camera to the reader - 9 small SPDT relays might work, plus the on/off and pushing the button to take the pic. Cost looks similar to Dippy's link. I'll keep researching.

I'd forget USB cameras if I were you. It is not easy.

And hacking camera/SD/Serial - phew good luck. And I'm looking into an SD interface with a few more (useful) features.

The device on the link I gave has serial output and a good command set, but I suspect it may shoot out too much data for PICAXE to handle.

But keep looking, something ideal may crop up.

The sensor inside a PCs Optical Mouse is
actually a very Low Res Camera, in the
order of 36 to 64 Pixels.

There may be some applications the larger
picaxes could handle, a bit beyond my level
of experience though.
I'll just sit and watch ~ ;o)

This is a link to a project on Make.
the guys used a 555 timer to control a digital camera. If you can do it with a timer chip you can easily do it with a picaxe.

http://www.makezine.com/blog/archive/2007/05/555_timer_five_boro_bike.html

That's just your average basic time-lapse. I thought Drac wanted to capture a frame of image... to process pixels?

Edited by - dippy on 11/05/2007 14:49:34

If you do a 'Goggle' on &quot;Slow scan TV&quot; it should give some clues and tips about sending video data 'at your leisure' as apposed to the 6Mhz bandwidth required for 'standard' composite colour signal.

I have played around with the suggested optical mouse chips but the pixels are layed out in very odd patterns making difficult to reconstruct into a 'picture' the other end. Gave up in the end and used a Z80 digitising board sold by Maplin which unfortunately is now discontinued.

I do not know if this will help, but I thought it interesting that a IC had a 400 DPI, 128&#215;1 photodiodes. &quot;Arranged in a linear array. Light energy impinging on a photodiode
generates photocurrent, which is integrated by the active integration circuitry associated with that pixel&quot;

<A href='http://www.datasheets.org.uk/datasheet.php?article=3375246' Target=_Blank>External Web Link</a>

has anyone used the Agilent ADNS-2610??

it would seem that this is a very good choice for this kind of thing, a guy over here: <A href='http://spritesmods.com/?art=mouseeye&amp;page=1' Target=_Blank>External Web Link</a> has got one working as a scanner!!

maybe this could be used in next years micro mouse! (still going ok, if anyones still interested: <A href='http://www.ben-howes.co.uk' Target=_Blank>External Web Link</a> been keeping it updated.

Ben

 

The mouse video looks very cunning. However, it is a bit frustrating that one can have a full colour hi-res picture from a webcam costing &lt;$20 and can't access the data!

USB hosts might solve the problem, and would incidentally solve a lot of datalogging problems as well. Imagine a picaxe with 1G of scratchpad ram from a USB!

SD ram cards used in digital cameras are backwards compatible with MMC protocol which actually appears to be an RS232 protocol <A href='http://homepage.ntlworld.com/seanellis/mmcserial_pro.htm' Target=_Blank>External Web Link</a> Only catch - baud rate is 115,200. Anyone overclocked a picaxe to that speed?

Parts seem to be 'almost ready for market' eg <A href='http://www.fgcvme.co.uk/page6.html' Target=_Blank>External Web Link</a>



Edited by - Dr_Acula on 13/05/2007 13:29:29

I believe that the last link is being updated to include an RTC (so that file creation date/time is inlcuded) i.e. it behaves like a Basic language controlled file system on your PC.

Theres a huge amount of scope with that picaxe memory card thing. Just imagine creating a computer peripheral, but not needing to supply a driver or application program. All the software the device and the PC would ever need could be stored inside the device.

After the suggestion of USB cameras i googled it and got this: &lt;http://www.faculty.iu-bremen.de/birk/lectures/PC101-2003/14usb/FINAL%20VERSION/usb_protocol.html&gt;
looks complex. But i was wondering since u can get a USB download cable with PICAXE, is it not possible to use similar interface?

Also there are some CCTV cameras (miniature with good res that output raw video so why not just take that as a input connect the PICAXE to a XBEE and u have remote monitoring.

The USB-to-Serial cable sorts out the complex interfacing between the PC's USB and PICAXE, the PICAXE still only deals with the simplistic serial and knows nothing of USB.

You'd need a PICAXE serial-to-USB interface ( which is not the same as USB-to-Serial ), and that would also have to understand whatever USB device were connected. It's possible, but not apparaently available.

The USB Picaxe download cable won't really give you access to USB. Its a USB to serial converter so you will only really have RS232.