Just received notification that the PCBS have been shipped via FEDEX, so should have them within the next couple of days.
Part 2 – RFM12 Hardware Interface
Ok I have finally had a little bit of time to work on things (will be short lived as I’ve just bought a house and moving in the next couple of weeks Aghh!!).
Things are getting very close to reality after many design changes, the very nearly final Strobit Trigger base board, aka a modified Ardiuno BT board, with the Bluetooth removed and now fitted with the RFM12B SMD Tranceiver module and an external SMA antenna connector. The Eagle 3D side of things still needs work as some components are not shown and the inductor for the DC-DC converter is incorrect, but you get the basic idea right!
Why have I gone to a non-dedicated trigger board?
Well a couple of reasons, initially to cover myself from any patent issues that might have arrisen had I used a dedicated wireless triggering device, but mainly to allow better expandability. Why have a dedicated trigger with all the fruit and only use half of it, this way dedicated boards can be used, i.e. standard trigger, or sound/light trigger, sequences etc. Another reason is that the Ardruino is very well established and supported in the open source community, especially when it comes to the firmware libraries etc, it’s already been done. also I can use these in my robotics hobby as well, not just for photography.
Ok onto the board features:
- Fairly compact same size as ArduinoBT
- Standard Arduino Pin headers, so should be able to use with existing shields.
- Will operate from as low as 1.2V, so should work from x1 NIMH AA easily enough.
- RFM12 Tranceiver, up to 300m range (as per datasheets, although it does depend on the datarate)
- SMA connector so you can connect an external antenna for better reliability and range, or remove the SMA connector and use a piece of wire as the antenna.
What is left to do?
- Well the design is pretty well done, I want to get some prototypes made so I will be sending it off very shortly for fabrication.
- Different variations of shields need to be done, first one being stock standard strobe type of triggr, input and outputs, then others as needed
Due to the number of requests for help in getting a link operation with the RFM12 tranceiver, I’ve set up a dedicated topic on the forums. http://forums.everythingrobotics.com/index.php. Please post any cries for help there, that way no information is lost in the comments of my blog or my email inbox
During the development of the StrobIt Open Trigger Project I’ve been using the HopeRF RFM12B Tranceiver as the RF module. The learning curve was fairly steep so I’ve decided to create a series of How-To articles so that others can easily get the module up and running fairly quickly for their project of choice. So far I’ve already slated these for use in a few other projects around the house, both robotics, home control and weather station related.
20/03/09 *UPDATE * This project now has a new home and is actively being developed on Google code project hosting http://code.google.com/p/strobit/
IMPORTANT This page is no longer being being maintained please go to the new project page.
Welcome to the Strobit Triggr Project, an open source hackable wireless trigger used in photography lighting by using low cost strobe units triggered remotely via RF. This was started while trying to find a cost effective and reliable solution to the commercial alternatives out there. At one end of the market is the Ebay or Cactus Trigger, which is low cost but rather unreliable. At the other end of the market there is the industry standard, Pocket Wizards, very reliable, but very expensive (i.e. way out of my price range).
What I wanted to do was to create an open platform that anyone can easily build for a low cost and then be expand upon by the community. The pair of prototypes I’ve built were a proof of concept that I can get a camera to trigger a strobe unit reliably at a low cost. From early tests it appears that I’ve succeeded in my goal, but further testing is required.
Project Status :
- Prototype successfully working in single master/slave configuration !
- (20/03/2009) Project now has a home at Google Code – http://code.google.com/p/strobit/
- Hardware Design
- Software Design
- User Interface
- Hardware Prototype
The strobit hardware design is covered by The TAPR Open Hardware License. Please see http://www.tapr.org/ohl.html for further details.
Downloads – Files associated with the project
Tests – Tests done so Far
In the Wild – Version of this trigger made by others
I’m toying with the idea of putting together a low cost kit for the enthusiast. i.e. PCB, pre-programmed PIC, etc. So we could all benefit with a bulk order of the components. If your interested please email me using the contact form the top menu or use the mailing list signup on the right to give me an indication of numbers interested. Once I finaliaze the design and get some idea of numbers I’ll get a better idea of price. At the moment it will only be available in kit form due to FCC and other Licensing regulations.
- Higher Sync Speed.
- Frequency Hopping.
- Forward Error Correction.
- Power management.
- UI to change settings, Channel etc.
- Save settings in Flash memory.
The RFM12 module is a pain to prototype with due to the 2mm header (won’t fit into the breadboard), so I’ve whipped up a prototyping board that brings out the pins to a standard header. It’s been it sent off for fabrication today so I should have back in the next week or so. I’m trying out www.batchpcb.com for the first time so will be interested in how they turn out.
In the meantime I’ve soldered on some wires but I don’t really like it.
After getting back into photography after many many years (and because Digital SLRs are so much cheaper) I’ve been an avid follower of the stobist website (www.strobist.com) for off camera lighting. To do this off camera lighting you need a way of triggering the remote stobes, some are wired, some are wireless either RF or Infrared, but obviously the easiest is via wireless. Well there are many solutions, some cheap (ebay triggers) some expensive (Pocket wizards) and you get what you pay for, the cheaper ones (of which I one a couple) are notorious for false triggers, while the Pocket wizards are way out of my price range.
So in the true spirit of Open Source, of which I’m a huge fan, I’ve proposed an open source wireless trigger for the strobist community. Initial thread found here – www.flickr.com/groups/strobist/discuss/72157602088957861/ So far the response has been
I’ve now setup a wiki for a brain dump of ideas http://wiki.everythingrobotics.com and will shortly have a mailing list up and running.
forums are now also up and running http://forums.everythingrobotics.com hopefully these will eventually fall under the strobist.com domain
This Blog is a collection of my geek projects and things I’m doing at the time. Unfortunately due to a busy life (like most out there) the blog may see some in-action for periods of time, however don’t despair, as I get around to updating things eventually and the blog posts go through a burst of activity.
My Interests (in no order what so ever): Embedded Development, Photography, Wireless Sensor Networking, Home Control, CNC.
My Photography: www.flickr.com/strobotics/
Tweet Me: www.twitter.com/madeinoz