WANSEN WS-603C mod

The RF trigger transceivers made by WANSEN do a pretty good job. I use those in my Canon digital gear.
However, next to the digital stuff, I also shooting film. The cameras I use for this might have a hot-shoe... at max.
Wanna doe wireless with random and oldskool gear?
Here is the solution: get some WANSEN WS-603C an modify those. No, this is not my idea, I found this guy who modified a Yongnuo RF-603N trigger system this way. Here's another chap showing a modification of a RF-603C in video.

The mod add 3V via a 100kOhms resistor to a pin of a multipole hot-shoe. The 100kOhms resistor would be called a "pulled up", i.e. pulling up the potential w/o adding the current. A very safe bet for any electronics.

The WANSEN units seem to be slightly different from the Yongnuo units. So, take care to modify your RF trigger in an appropriate way. Actually, within different WANSEN units, the wiring is different!
I have to say, that my mod is pretty tolerant to various layouts of the main PCB, since it is oriented on the PCB assigned to the hot-shoe.

the pin on the hot-shoe sensing the presence of a camera

here the pin ends, in the middle!

One can attach the switchable pull-up on either the hot-shoe, or the main PCB.
For reduced confusion, I decided to apply the pull-up to the hot-shoe.
Looking out for "done work", I decided to remove the 3.5mm trigger socket, to make place for a switch. One of the terminals of said switch came conveniently close to the hot-shoe's PCB's solder patch for the relevant pin. A very short piece of wire connects the switch with pin, enabling "pull-up".
The green arrow of the following picture indicates the location of the added pull-up resistor.

the mod asks for a 100kOhms pull-up resistor (connected to the battery terminal)

The unit functions as a flash-trigger now... that's the supposed primary use.
Many modern cameras require their very own speed-light systems. Modifying existent systems, such as the WANSEN or Yongnuo, may not provide TTL metering, however, those system form a perfect alternative to the overpriced PocketWizzards.


Actually, I use those trigger to pop a remote flash with an AGAT 18k.

receive mode, all three

device in the middle set to transmit (cf. green LEDs)

Beneficially, the WANSEN and the Yongnuo system are fully compatible in terms of functions.
Personally, I got 2 Yongnuo units and 4 WANSEN units...I will have a hard time figuring out how I can use 5 speedlites....