Radiopoppers with custom cables

i’m really not much of a tinkerer.  i don’t have my own soldering iron  and i had to borrow one from my dad for this project.  but i do like understanding how things work and the simple fact is this is so very simple, it was foolish not to do it myself.

i recently bought a set of Radiopopper JrXs which are radio controlled flash triggers that work really well.  they can work in a mode that just fires a flash or studio strobe in a very unintelligent manner.  whatever power setting the strobe or speedlight happens to be set to, that’s how much light you’ll get.  however, if you connect the receivers to an Alien Bee studio strobe (of which we have 3 down at our studio) using the data cable (which is just a short phone cord), you can control the amount of light on the strobe with knobs on the transmitter that’s right on your camera.  this is a huge convenience, especially when you’ve got a light on a boom stand that’s 8 feet in the air.  and its a huge time saver because i don’t have to put the camera down, walk over to the light, adjust the power, then take another test shot.  and even more so, i can connect the transmitter right to my light meter and adjust the light before i even start shooting.

The accidental tinkerer's workbench

the Radiopopper folks also announced that there would also be another accessory called the RP Cube for the receivers that would allow you to manually control the output of Nikon and Canon speedlights using these same knobs on the transmitter.  the RP Cube was a small cube with a hot shoe to snap your flash into, and a stereo headphone jack to connect to the radiopopper receiver.  for location shooting, this would offer the same benefits as using the data cable on the studio strobes.  i thought, “great! send me two!!”  but, of course, its not going to be shipping for another 6-8 weeks.

i am an impatient man and so is the rest of the internet, apparently.  someone figured out that the manual control was done in the same way that most TTL metering is done.  full flash power is accomplished with a longer duration flash and lower power is accomplished with a shorter duration flash.  so, there are two wires, the trigger wire and the squelch wire.  the flash is told to start by closing the circuit on the trigger wire and its told to stop or turn itself off by closing the circuit on the squelch wire.  the radiopopper transmitter accomplishes this with some tricky timing and then radios the receiver to close the squelch circuit just in time to achieve the power level set by the knobs on the transmitter.

Homemade RP Cable and RP Cube!

so, by taking a Nikon TTL E900 cable that has the same trigger and squelch wires, its really easy to wire them to a stereo mini-jack to connect to the radiopopper receiver.  a trip to radio shack got me the stereo mini-jacks and a stereo mini-cable.  a trip to dad’s place got the soldering iron and some solder.  so after a couple bungled soldering attempts and another trip to radio shack, i’d finally had the cables wired up and they actually worked!  by clipping and saving the cable portion of the E900, i made an RP-Cable to manually control my flash by plugging it into the TTL control connector on the flash.  then using the E900’s hot-shoe cube , i wired up half of the stereo mini-cable to connect it to the radiopopper receiver.  the benefit of putting the flash on the hot-shoe cube is that it has a standard 1/4 x 20 mount so i can easily put the flash on a stand and it also has two other Nikon TTL connectors which means i could gang two more flashes together, having two or three flashes working in concert from one receiver.  that’s nice!

so now that i have all this cool control, i can do things like this…

Genna Bee - Freak Show Terror!

this was done by balancing the little bit of night time ambient light and adding some flash to highlight Genna. the flash was triggered with a set of radiopopper JrX transmitter and receiver.

Daniel, Sports for Kin

again, balancing ambient while adding a remotely triggered flash that was to daniel’s right side. notice the highlights in his hair and the right side of his chest.  since the sun was starting to set behind the houses here, this highlight is all from the SB-800 mounted on a hand rail to daniel’s right.