Request for Laser Pack project topic

[ZapBrannigan]

Hey Dingo,
my request for a project, as I mentioned before, is not strictly robot related. It is a DarkZone style laser pack.
However, I am not going to be using infrared for the actual shooting, but a laser diode instead. A laser is used in the normal dz packs just to give the user an indication of where they have been shot.
A laser diode would be better for shooting as one does not have to worry too much about focussing the beam due to the coherence of the light (There is a little bit of spread, but not much). Infra red spreads out due to differing frequencies contained within it. Hence, there is more power transferred over more distances with more accuracy.
The beam would be modulated on a particular frequency, with the digital signature (repeated many times within the beam) of the shooter encoded within. The receiver firstly filters red light only (colour of diode), then filters on the modulation frequency, then uses a shift register to bitwise rotate until it reaches the known header of the digital signature. The actual signature bits could then be read off.
This aspect can be considered a sub system that is portable and relevant to robotics, as the signature can be a fully encoded message.
A micro is used to store statistics, control death, allow different modes (ie, hitpoints, limited/unlimited ammo) etc.
RF could even be used to transmit live scoring, which is another sub system that is very relevant to robotics.
So there are a number of issues that I would want to discuss with our board members here

Cheers,
Michael

[Thrashbarg]

That's sounds like a good idea.

I'm thinking about how to synchronise the signals so there isnt any confusion. You would probably want a 12 bit shift register and use a start bit/stop bit method. Bit one is the start bit, then 8 data bits, a parity bit and two stop bits. Start shifting when the start bit is detected and count to 12.

Why would you want a focused laser beam? Wouldn't it make it more difficult to hit the light sensor?

[Dingo]

Sounds likea great idea. I don't have too much experience with lasers etc but I can certainly gather some info and post a project. Then anyone here who has info can add to it.

This link shows a AM radio laser transmitter
oatleyelectronics.com/pdf/k073.pdf

has both Tx and Rx shown.

This is all about the US military MILES system
www.fas.org/man/dod-101/sys/land/miles.htm

This is the FAQ over at Battlefield sports:
www.battlefieldsports.com/FAQ.htm

It is IR based but does have some useful info, especially about Micro design considerations and indoor/outdoor issues with IRs (don't know if LASER would be as affected)

[Bones]

Hi,
Nice project. A couple of months ago Silicon chip had some serial transmiter modules in an article (I'll find out which on tonight). The pic controller that they used had error checking an everything. Might be work a look.
Another question for Zap and any one else. Has any body built or have seen a circuit for an I/O controller that uses the PCI port. ISA was great but most motherboards don't have it any more. Plus it's 32bit.
Bones

[Bones]

Hi,
Silicon chip issues was November 2003 which uses Auzzy made RF modules and a programed PIC with all the error correction and protocols in it.
The May 2004 issue had the receiver module that output to 8 ouputs.
Other wise in another part of the forum I speak about another module. There are a few different types. Look in the electronic mags around the world for them.
bones

[ZapBrannigan]

Hey all,
thanks for the links and info. I have had a look at most of them and they are quite good.
Sorry Bones, have not seen/dealt with IO from PCI slots. I am sure that there are implementations around the web though.

Yeah, the project I have in mind is quite large. I will split it into small portions though and build up from there.
I'll post up an initial design soon when I have a free weekend to work on it

[Dingo]

another site with info

www.epanorama.net/circuits/laserlink.html

[upctoys]

I was looking at using this in a project. Hadn't really thought about it for your app but it might be useful.
www.cypress.com/support/app_note.cfm?objectID=A97D4159-88CE-44EB-9EB561B75C51A3AB&fname=PSoC%20Mixed%2DSignal%20Array&tid=A47EC41D-A212-4D8B-B3AA620F3AEB2978

If you havn't had a chance to play with the cypress PSOC you really should consider them. A controller with 16k flash, configurable analogue modules and a configurable digital section. I've used one as two single ended amplifiers with 12bit AD's that can be configured(on the fly) to be a single differential input channel with a 12bit AD. Both configurations with programmable gain sections

Although this app is only about driving a laser the PSOC's are capable of being made into a single chip solution for modulating/de-modulating the signal with all the amplifiers required.

Worth a thought. Chips can be got in OZ but not easily. I know they can be bought from www.digikey.com