Strobotics

I’ve started to document the Wireless Widget Board in the wiki, documentation is currently all over the place, but slowly getting there.  Currently I’m working on the build instructions so those of you that I’ve sent PCBS to can at least have a parts list.  

I’ve also put up an initial bill of materials. But it would be great if someone can do a Octopart BOM and share it.

Initial building instructions can be found here: http://code.google.com/p/strobit/wiki/Rfm12BuildingInstructions with more to come.

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I had a chance to grab a few photos of the progress so far, also helps that most of my components that I had on order arrived today so the boards has been kitted out with all the headers.  Now I can plug the prototype personality in, still waiting on my crystals, switches, and diodes.

This gives an idea of size. (I don’t have big hands either)  This board has a 900MHz 2dB GSM SMA antenna, prototype personality board installed and battery holder for CR123A Lithium battery. 

Different battery options, using x2AA with a switched battery pack soldered onto the board.

The SMA connector is a standard PCB straight SMA connector that has been soldered onto the edge of the board.  The board have been designed for the Sparkfun PCB edge mounted SMA connector (SKU: WRL-00593), however I found that a standard PCB SMA connector will do the same job, the distance between the centre pin and the ground pins is the same thickness as the PCB and all the pins line up with the Sparkfun footprint, the centre pin fits perfectly and so do the two bottom ground pins, only difference is the two top ground pins don’t get soldered.

One of the LEDs flashing….Its Alive!!!!

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Today I did some testing on the RF side of things,  nothing scientific, just walking around the house seeing if it would dropout or report bad checksums, I’m happy to reports all is working as expected (using the 915Mhz RFM12B module)

The tests are done by using the RFM12B Example sketch found in the JeeLab RFM12B library by Jean-Claude over at Jeelab (RFM12B Arduino Library)

This library runs unmodified on the wireless widget board, just follow the instructions in the README about setting up node ids.

From the preliminary testing using some compact 1/2 wave GSM 900MHZ/1800MHZ antennas (http://www.dealextreme.com/details.dx/sku.5237)  I’m easily getting all the way around the house with no dropouts, have yet to do outside tests.

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PCB designs were finally sent off to Gold Phoenix yesterday, a bit of a delay as I had been wanting to complete a couple of other designs to fill up the panel before sending off.  Three different designs, Strobit RFM12B core, Experimental 2.4Ghz core and a prototype personality (think arduino prototype type shield) have now been merged using gerber merge into a 10” x 14.5” panel.  Hopefully they should be back early next week.

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Ok not quite finished, but almost there!  I’ve had to make a few minor changes.  I’m glad I’ve taken the time to learn and play around with Eagle 3D, it had highlighted some potential clearance problems.  Rather than rush things I’ve decided to take a bit of time modelling than fork out my $$$ and get some prototypes made only to find these problems down the track and could have avoided.  Granted Modelling is not a silver bullet, and I guess I could be here forever, but now I’m a lot happier.

Changes:

• Moved SMA antenna connector back from front edge of the PCB as it was hanging over slightly.  This connector is optional at assembly.  The pad can be used to solder on a wire antenna instead.
• Changed switched power side on the switch, The switched side of the On/Off switch was very close to ground plane coming under the switch so had the potential to short, now is nice and clear.  I’ve also added some more ground plane clearance around the switch contacts just to be on the safe side.
• Added solder jumpers for LEDS, probably don’t want these enabled if a personality board is on, but it gives you the option to use them or not, and re-use the I/O if required.
• Moved vias and tracks away from standoffs.

Todo:

• I think I really need to isolate the 2 power sources from each other, i.e. the Power from the USB and VBAT, so I’m looking at putting in a BAT54C barrier diode.  Just need to research it a bit more.
• Still don’t know what to do with the ICSP connector.  I will probably leave it there with the option of putting it on at assembly.  I’m pretty sure that it will clear any personality board with a bit of care.  Modelling the personality board is my next step.

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I’ve been playing around with Googles sketchup over the weekend and have created some components, one the RFM12B module and a basic camera hotshoe to scale.  It’s been a great little exercise in learning both Alibre and Sketchup as I’ve been wanting to get some 3D modelling practice, I’m finding that it’s easier to create things in Alibre and then export them to Sketchup.  Alibre does not support texture mappings in the drawing or export to POV, but Sketchup does it brilliantly, while on the other hand, Alibre’s3D modelling is very easy to use.

Currently the workflow is:  Model in Alibre –> textures in Sketchup – > POV Rendering– > Eagle3D Components.

Keep an eye out for more to come.  I’ve started a Stobit Collection in Googles 3D warehouse  for use with this project and will be adding to it as I go.   I’ll be putting the Eagle3D component files that I’ve created online shortly.

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Ok here is the 1st basic trigger personality board.

Features:

• x4 LEDs for visual indication.
• x2 Push Button Switches, one tied to input for manual triggering/testing, the second independent, could be used for channel or function selection, both could used in conjunction with LEDS for advanced function selection.
• 1 Strobe output. 400V Max (so will work with older type strobes)
• 1 protected TTL trigger input. 
• Small prototype area.
• Low profile, All large components are mounted underneath.

Still a little cleaning up required but basic functionality is there.

Still TO DO:

• Change MOC3023 to SMD footprint, I don’t really want the possibility of a large strobe voltage right where a thumb might be.

Basic Triggr Personality PCB

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All the design files and software are now available online for Jan Gentschs M8 Triggr Implementation.

Files can be found here.

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IMG_8198.JPG, originally uploaded by jgentsch.

The first StrobIt Triggr seen in the Wild!

Jan has made a neat and well packaged version of the StrobIt Triggr. Based on the AtMega8 it runs from a single AA battery. Well done Jan!!!

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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

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I was surprised when I looked at my blog today how long ago my last post was, nearly a month ago…bugger where has the time gone – it’s nearly christmas again LOL!  Way overdue for an update I think.

Well I can tell you where the time has gone, mainly sourcing component suppliers and getting prices in for the Triggr boards, not to mention a redesign.

Have had a delay also with the design, which really was a lawyer thing.  After speaking with a few people and my laywer about some issues initially raised on the forums about the existing patent held by the Pocket Wizard People, I’ve decided to make some fairly significant changes to the design, All the functionality is still there and its still expandable, actually probably more expandable than it was before.  I just needed to make it a non-dedicated remote camera trigger, in fact it’s not really a trigger at all, confused? well all will be revealed

In short these changes have been made but I need to finish the new PCB, which I’m hoping to finish this week, and then get some prototypes underway, hopefully I will get a 3-D model of it in it’s current form on this site as soon as I work out how to use Eagle 3D.

Most of the prices are in although I’ve not calculated the price based on the new design, it is still looking good, the biggest killer so far is freight.   When you can get resistors at $0.0016 each in reel of 4000, it doesn’t work out to be that expensive, however at freight of AUD$45+  it all starts adding up when you are needing different reels of capacitors resistors from different suppliers etc.  So…..at the moment in between finalizing the new Atmega Board design and my real day job, I’m sourcing a turnkey supplier and assembly so that I only need to pay freight once.

As a side note looks like best price breaks start at 1000 units for most things so I need to make sure I do my numbers correctly so I don’t end up with alot of expensive paperweights that I can’t get rid off LOL.

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I’ve created a page for the trigger project and have just updated it all about the prototype and testing etc.  Over the next few days I’ll be posting source, photos etc

Found here – http://blog.everythingrobotics.com/strobit

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Well I finished the two prototype boards tonight with some minor changes and a bit of troubleshooting, still lots to do though.  I now have them triggering.  Will be testing further over the next few days to get indication of range etc.  So far it is only syncing at 1/100.  I will be posting more details , schematics, firmware etc as well as I get time.

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After a hectic and very hot Christmas (41DegC) I managed to get some development time and finished 2 prototype boards.  My RFM12 header boards still have not arrived, caught up in the christmas mail I guess   So I’ve had to resort to hand soldering some wires to the header in the meantime. (Murphys law suggests that as soon as I finish soldering these headers the breakout boards will arrive in the mail)

Tomorrow/Later tonight I will test both of them and see if I can get a remote trigger happening woohoo.

Sorry about the quality of the photos as they were taken with my phone

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I’m pleased to announce the very ALPHA release of the RFM12 library for the wireless HopeRF RFM12 FSK tranceiver module that I’m using for the strobist open trigger project.  It was developed under BOOSTC for the PIC embedded controller, but should be easily ported to any compiler.

Most of it is untested, hence the alpha release, but it’s a good starting point.  Everything is fairly well documented, but like any project could do with more.   Please send me any bug fixes/improvements that you may find while using it.

Download:  rfm12-0_1a.zip 

Features:

• 433Mhz and 915Mhz HopeRF FSK RFM12 modules supported
• Initialisation with a basic config
• Set Frequency
• Set Receiver Bandwidth
• Set Receiver Gain
• Set Receiver Signal Strength Indicator Level (RSSI)
• Set Transmit Power level
• Set Transmit Modulation
• Set Baud rate
• Enable/Disable Transmitter
• Enable/Disable Receiver
• Transmit a single byte – blocking
• Transmit a buffer of data – blocking
• Receive single byte – blocking with timeout
• Receive ‘x’ number of bytes into buffer – blocking with timout

 TODO:  (not in any order)

• Testing
• Howto documentation
• RFM12 Interrupt handling 
• Non-blocking Tx/Rx routines
• MSSP SPI implementation (current SPI implemented via bit bang)
• Frequency hopping
• Custom configurations

License:

Released under the Creative Commons – Attribution-Noncommercial-Share Alike

Disclaimer:

Please use this library at your own risk.  I will not be held liable for any damages.

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