I’ve been playing around with the Arduino Diecimila and the ATMEGA168 over the last couple of weeks to better familiarise myself with the AVR ATMega168 MCU, I’ve been using PICs on and off the last few years, but the decision was made to use the ATMEGA as the MCU of choice for the Strobit Triggr project, mainly due to the open source tool chains available, and the simply programmer required.

In short I’m glad I’ve made the switch and I must say I’m loving the learning experience.  I’ve moved from the Arduino software development platform as I found it very limiting and am now using the open source avr-gcc (win-avr) and Eclipse, using the AVR plugin and CDT plugin as my development platform of choice, I’m comfortable with eclipse as my editor as I’ve been using this for my Java development for the last 5 or so years.

As a task I set for myself to learn the onboard peripherals,  I’ve created a Weather Shield for the Arduino, so far it has the RFM12B RF module, DS1307 RTC, HH10D Humidity Sensor, a HP03D, combined barometric pressure and temperature sensor, and soon to have a light sensor and Dallas 1-Wire interface for talking to the Dallas Weather Station that I’ve had lying around in a box for the last 10 years, (yes one of the original ones released by Dallas in 1998, I’ve been waiting to move in my house for a long time),  I’ll post the weather shield design up on a separate topic later, but suffice to say, I’ve enjoyed playing with the SPI, I2C, ICP, UART and onboard timers.

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

Files can be found here.

During the prototyping of the StrobIt Triggr, I found that I could only hit the maximum bit rate of approx 12000bps, this is a far cry from the reported 256Kbps, so what was I doing wrong?

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Well my new tool, a LogicPort Logic analyser from http://www.pctestinstruments.com/index.htm, arrived last week whilst in the middle of our house move and I’ve been itching to try it out, well last night I made time to play with it.  The result is, man I wish I had one of these beasts earlier.

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Part 2 - RFM12 Hardware Interface

In this next part of the RFM12 tutorials I’ll be covering the hardware interface, signal descriptions and how you go about hooking it up to the MCU of your choice.

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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!!!

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

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.

Well I’m back from my short break away and arrived home to my inbox filled up with forum activation emails which I’ve identified a large sample as spam bots related. So to kickstart the forums off again I’ve upgraded to the latest version of phpBB3 which has much better features especially in the user management and (anti)spam areas.   All users and posts have successfully been migrated, however that if anyone had registered and NOT received their activation email prior to the upgrade then please re-register, or contact me.

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

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.

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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.

What did I say in my last entry about murphys law and my RFM12 header boards?  Guess what arrived in the post today lol…..

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