YS50 is not YS110

I had created an Arduino based controller that would monitor my camera hot shoe X contact and then fire a YS50 strobe based upon a power setting level control.

I had been using some old spare Sea & Sea YS50 strobes for my testing since I did not want to damage or wear out my real strobes. It was now time to hook the Arduino up to my real Sea & Sea YS110 strobes. I expected success since I was not doing anything too sophisticated. I got utter and total failure. The YS110s did not fire consistently and did not produce a consistent power output.

Packaging the Arduino

The next challenge was physical. I needed to mount an Arduino Pro Mini board in my reclaimed Sea & Sea TTL converter housing. Should be easy. The housing was much larger than the Pro Mini board. The Pro Mini board was smaller than the Sea and Sea board I removed from the housing.

Don't Forget the Camera!

My test rig and YS50 mule strobe were all working fine. It was now time to get serious and start to hook it up to real equipment.

At first I thought I should tackle jamming the Arduino into the Sea & Sea TTL converter housing. But I decided that I needed 100% confidence in my setup before I started to solder wires to the Arduino. Soldering was a final commitment.

So the next step was to include a real camera into the setup. This required more brain power than I anticipated.

Practical Arduino Quench Control - Part 3

The next step was to hook my Arduino Quench program to a real power level control switch. Seems easy, but once again I hit some interesting potholes along the way.

The Sea & Sea TTL converter housing came with 3 rotating controls:

Practical Arduino Quench Control - Part 2

The next step was to be able to control the power output of the strobe. The Nikonos TTL wired interface provides a Q (quench) signal line. This is used to instruct the strobe to stop firing. If the Q line is unused the strobe will fire a full dump each time it is triggered. If the Q line is dragged low after the X line then the strobe will stop firing. The longer you wait to assert low on Q the longer the strobe dump is. If you wait too long to assert low on Q then the strobe will perform a full dump. This all works when the strobe is in TTL mode.

Practical Arduino Quench Control - Part 1

Now that I had determined how to properly structure my real-time code for the Arduino, it was time to start controlling my strobe.

Practical Arduino Real-Time Control - Part 2

Inconsistent test results meant that I needed to step back and examine how I was using the Arduino. Due to the single threaded nature of the runtime environment, I was forced to use a single loop function to handle all inputs and outputs. I now needed to make the loop execute on a consistent basis in order to provide real-time behaviour.

This caused me to adopt a more sophisticated approach to my Quench control program loop:


Strobe Quench Controller Operational Theory

I now needed to transform my Sea & Sea TTL converter into an open loop manual power controller for my YS110 strobes. This would provide a single point of power level control so that I did not need to individually adjust the built-in power knob on both of my strobes. Supporting the Canon eTTL protocol was shuffled to the back burner for a while.

The physical TTL converter provided the following features:

Pivot! Decoder -> Quench

My prior work had established a reference set of data messages exchanged between my Canon G16 and a 430EX II flash. Now all I had to do was workup an Arduino program to mimic a 430EX II to the G16 and mimic a Nikonos camera to my Sea & Sea YS 110 strobes.

So far I had been focused on the Canon G16 digital side of my problem. I considered the strobe side to be simple. So I had ignored it. I had focused on developing a Sniffer program that would characterize the G16 to 430EX II protocol. Next step was to think about the big picture decoder problem.

Canon eTTL Protocol Investigation

Having established an Arduino based sniffer complete with an IDE I was finally ready to do some actual real investigation of the Canon eTTL protocol - as spoken by my Canon G16 and a 430EX II flash.

My prior work had indicated that there was constant chatter between the camera and flash. Even in an idle state.


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