No offense intended to Doc & Lefty, but ain't there supposed to be a COS sumpthin, or SIN sumpthin in there somewhere (although i seem to remember something about the DC ohms law beeing a fair approximation sometimess)?

And this:

And these:

The original poster has not posted since May, but here goes anyway:
If you are talking about Hen Long RC Tanks, these files might help:

The Nikon D50 does not have an external shutter release port.  You can onlu use the regular manual shutter button, or, an IR fob.

Wiz,
I think a better idea is to change the SET BIT instructions in the twi.c initialization to CLEAR BITs.

I would probablly have to do the same if I use I2C Master lib (to change the default settings from enable pullup to disable pullups).

Grumpy_Mike,
Oops, yea, that sounds logical and dangerous... Rats,, but thanks for saving the lives of a couple of breakout boards.  I've found the code that turns the pull ups on in twi.c (under /libraries/Wire/utilities/).  Not famiiar with library I2C_Master.  Google, here I come.  I knew you were the guy to ask.  Many thanks.

Smoke,
in production, yes,,maybe, but, in development, no.  I need easy access to the serial monitor for debugging.  Good idea though.  Thanks.

Crossroads, yea, sounded good to me to.  Oh, well, I guess that I'll just rip the Wire & utility libs.....

Thanks Guys.  Good one to ya'.

Crossroads,
Yes sir, Bi-directional comms between the periph and the Arduino.  In the thread which was referenced, I think it was you who mentioned TXBxxx devices, but they don't seem to work too well with I2C (0108's in particular).  A TI support engineer suggested a PCA9306 and is sending me two samples, but those little bugs are really small....

So, you think that, electrically, it should work?  Given that, what do you think about putting inline asm code in, after the wire.begin, to reset the port bits and turn the pull ups off that way??

Thanks for the response and getting me in the right board.

I'm not sure if this is the correct area for this issue, but it is the most applicable that I 've found.

History:  I have some 3.3V I2C peripherals which are not 5V tollerant.  I2C friendly,Bidirectional Level Translators would seem to be the common solution.  I have a real hard time hand soldering mini SMD's and do not like reflow.  Plus, "Keep It Simple Stupid" works really well for me....
Mike Cook (Grumpy Mike) posted a response to another thread in the general electronics section which indicated that: 1) if you could 'HACK' thw Wire library to turn off internal pull ups ( on A04 & A05), and 2) (i think that this is what he meant) connected the Analog Ref in to 3.3V, and 3) ran your pull ups to 3.3V bus, you could do I2C with these types of devices without the need of level translators (again, this is what I think he was getting at.  Have'nt been able to get him to respond to the thread to confirm or deny).

My Objective:  If my assumptions are correct, why can'nt someone add a function to (NOT the Wire lib, but to:) twi.c in /libraries/Wire/utility/... to turn off the pull ups used by I2C?
"twi_init(void)" in twi.c (arduino 0022, I haven't had a chance to check 1.0 yet) sets the port bits to enable the pull ups, based upon the type of controller.  Is there a simple way to add parameter checking to stop this process, or, a function to reverse it?  Or is there a way to do it in the user's (my) code?

I'm old and senile, but I aint stupid (though many others have disputed that issue), but I don't have enough smarts to put this one together....

Thanks for any help and consideration.

Let's see.... A swashplate assemblly, Ball to servoarm linkages, Lots of wire-ties,,, (source, maybe a crashed Collective Pitch RC Hellicopter), which is a good thing, cause you'll also need the Helli transmitter and reciever (to get the mix logic), a BEC to power the reciever,,,  Maybe a second person to pilot the quad, But I really wouldn't worry too much about that part, as soon as you try to lift off the quad, the COG imballance will give you a nice, heafty, positive pitch, which will nose dive the quad, likely smashing the camera and quad to bits.  But it looks like it would be really funny (as long as it is not your quad and camera).

Unless you are wanting to be able to roll your camera 30 degrees or so right or left of horizontal, you would be better off with a simple X-Y gimble friven by two servos.  But, there is a reason that the camera rigs you normally see on Helli's and Quad's are located under the center of (or close to the center of) the aircraft.  It's trelated to things COG, COM, MOI, & MOM (ie: Ballance and controlability)

Grumpy Mike,

Are you saying that if I can 1) disable the internal pullups on A04 and A05, and, 2) plus the Analog Ref Voltage input into the 3.3V, 3) connect, say 4.7K resistors between SDA and 3.3V, and Data Clock and 3.3V,  That, for I2C, I can do WITHOUT those nasty SMD buggers (currently trying to design board with TI/Nsc Pxx9306,  with my fat old fingers and old and abused eyes, it's a real challenge)??!!

Oh THANKYOU, GREAT ONE!!
Sorry for the quasi-necro post, but I just found the parent topic.

CROSSROADS, The TXB's don't work very well for I2C. Do you have some trick that makes them servicable for I2C?

Good one to all,
Splat

Excellent tretises on zener OV protection and noise suppression, Mike & Doc. Thanks.
But, not to go too far off topic, isn't the symbol in the OP's schematic that of a 'Fast Recovery' Diode, not a Zener??

"when you come to a fork in the road, take it.."  (Yoggi Berra, American Baseball celebrity)

I could be wrong, but I do not think that shielding is the answer to your potential issue. 
I would suggest electrically conductive connection between all the foam parts and then connect that "circuit'" to the arduino's ground.

Jackie, me boy, you make life too simple......

My compliments on an elegant reduction of the solution.