RF Transmission Requirements

All hardware design discussions

Moderators: seaton, strogg

RF Transmission Requirements

Postby wpeloqui » Sat Sep 22, 2007 10:40 pm

Hi,

What requirements are needed for the RF transceiver? A simple one shot pulse? Small packets of data? I am a software engineer with a good background in digital communications. I am also a ham, and finishing off my second degree in electrical engineering.

I don't know much about photography. That is why I am following the Strobist blog site, to learn more!

There are RF xceiver modules about the size of a nickle that would far surpass most of our needs. I can envision a xceiver, a hotshoe / Sync cord interface, and a couple buttons.

I have friends and coworkers that can design and implement any packaging your mind can fathom.

Willie
wpeloqui
 
Posts: 1
Joined: Sat Sep 22, 2007 10:23 pm

Postby seaton » Sun Sep 23, 2007 6:19 am

I woulld say small packets of data, one shot will be prone to interference, hence the problems with ebay triggers.

There is an active thread on this in the wireless section atm. http://forums.everythingrobotics.com/viewtopic.php?t=11
seaton
Site Admin
 
Posts: 134
Joined: Mon Jan 23, 2006 8:48 am
Location: Bunbury, Western Australia

Re: RF Transmission Requirements

Postby TwoLeftFeet » Sun Sep 23, 2007 6:52 am

wpeloqui wrote:Hi,

What requirements are needed for the RF transceiver? A simple one shot pulse? Small packets of data? I am a software engineer with a good background in digital communications. I am also a ham, and finishing off my second degree in electrical engineering.

I don't know much about photography. That is why I am following the Strobist blog site, to learn more!

There are RF xceiver modules about the size of a nickle that would far surpass most of our needs. I can envision a xceiver, a hotshoe / Sync cord interface, and a couple buttons.

I have friends and coworkers that can design and implement any packaging your mind can fathom.

Willie


Cool!

Data packets will need to be sent at some point in time. I envision the design working in layers, where the data protocol that we come up with will be used to control the TTL stuff later on. The wireless side has to basically support the data protocol, and not be prone to interferene (ie plz no 2.4GHz crap!).
TwoLeftFeet
 
Posts: 12
Joined: Sun Sep 23, 2007 5:52 am
Location: Toronto, ON

Re: RF Transmission Requirements

Postby robb » Sun Sep 23, 2007 10:49 pm

Cool!

Data packets will need to be sent at some point in time. I envision the design working in layers, where the data protocol that we come up with will be used to control the TTL stuff later on. The wireless side has to basically support the data protocol, and not be prone to interferene (ie plz no 2.4GHz crap!).



Anything we design is going to operate on one of the ISM unlicensed bands, which are all pretty noisy because, well, they're unlicensed. 2.4 GHz isn't particularly bad. It does mean you absolutely need to transmit a small data packet and preferably have some error correction to make your link more reliable.
robb
 
Posts: 2
Joined: Sun Sep 23, 2007 10:44 pm
Location: Calgary, Alberta, Canada

Postby JonSenior » Mon Sep 24, 2007 5:33 am

robb said:
2.4 GHz isn't particularly bad. It does mean you absolutely need to transmit a small data packet and preferably have some error correction to make your link more reliable.


The transmitter modules that have been suggested so far seem to include address and error correction in the protocol. If the device says that you've got data, it means it's supposed to be there! I agree that we can't rely on just sending binary high and expecting it to be reliable.
JonSenior
 
Posts: 60
Joined: Fri Sep 21, 2007 7:27 pm
Location: Paris, France

Postby robb » Mon Sep 24, 2007 5:44 am

Yup. The little all in one radios people are suggesting are great. They take care of error detection for you, by sending packets of a byte or two of data. For basic functionality our software should only have to send a signal, say a 1, to trigger a flash reliably (underneath the radio will send more than just that, of course).
robb
 
Posts: 2
Joined: Sun Sep 23, 2007 10:44 pm
Location: Calgary, Alberta, Canada


Return to Hardware

Who is online

Users browsing this forum: No registered users and 1 guest

cron