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Assembly and Operating Instructions for Kits


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Operating Instructions for the Multi-Trigger System (MTE or MTEconv)


Assembly instructions for other kits


These instructions apply to the original Multi-Trigger Enclosure for a breadboard as well as the Multi-Trigger Enclosure converted to use with a PC board.





Powering the MTE

The delay unit

The photogate

The sound trigger

The external input

Triggering a camera with the Camera Opto-Switch

Using the Opto-Switch to trigger a flash unit

Using wireless transmitters

Reported issues




The starting point for this manual is that you've already assembled and tested your Multi-Trigger together with the enclosure (assembled unit shown above) and that you've also prepared the input and output cables. For reference, all components of the Multi-Trigger system are shown below. Those that are not included with the MT-BB and the enclosure kit (MTE) are indicated as accessories. However, use of all the components will be described in this manual.


Click on any image for a larger view.

Included with the MT-BB and MTE (assembly required)

Photogate cable (interrupter type) with 3.5mm stereo connector

Photogate cable (individual emitter and detector type) with 3.5mm stereo connector

Microphone cable with 3.5mm mono connector

Accessories for the Multi-Trigger system

RCA to flash PC

RCA to flash foot adapter

RCA to Vivitar 283/285/2700

A trigger cable such as one of the three shown above is needed to connect the flash outputs of the MTE to a flash unit. The RCA to flash foot adapter is the most nearly universal.

(The RCA plug is supplied with the MTE; the cable and connection to flash are additional.)

Camera Opto-Switch box

Canon RS-60E3 shutter cable

Canon RS-60E3

Canon RS-80N3 shutter cable

Canon RS-80N3

RS-80N3 shutter cable

Sony S1


Trigger cable to connect TRIG output of Camera Opto-Switch

to camera output of the MTE


(The cable and one of the RCA plugs are supplied with the Camera Opto-Switch; the other RCA plug is supplied with the MTE.)

Nikon MC-30 shutter cable

Nikon MC30

Nikon MC-DC2 shutter cable

Nikon MCDC2

Nikon MC-DC1 shutter cable

Nikon MCDC1

Cable to connect Camera Opto-Switch to camera shutter

(Use the connector type for your camera model.)

The above row shows the components of the Camera Opto-Switch Kit for using the MTE to actuate a camera shutter.

External input cable

(The 3.5mm mono connector is supplied with the MTE.)



This adapter can be used to convert a 3.5mm mono jack to an RCA jack.

(This adapter is available here.)

AC-to-DC 9 V adapter

(This adapter is available here.)


Refer to the following photo of the MTE for the locations of the knobs, switches, jacks, and LEDs. Right-click on the photo and open in a new tab for reference.



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Note: It's best to have the MTE turned off when inserting plugs into the jacks.


Powering the MTE


The Multi-Trigger circuit is powered by 9 V DC. This can be supplied either with a 9-V battery or an AC-to-DC 9-V adapter. The AC/DC jack on the MTE accepts a standard 2.1mm plug such as the one on the adapter shown above.


In order to replace the battery in the MTE, first remove the box lid. When doing so, raise the lid carefully in order to avoid pulling wires out of the breadboard. If wires do come out, refer to the assembly instructions for the locations to replace the wires. If you use the AC-to-DC adapter, you don't need a battery but it's fine if you have one. When the AC-to-DC adapter is plugged into the MTE, the battery is automatically disconnected internally.


When the on-off switch at upper left is flipped to the ON position, the LED next to the switch will light. If you're operating on battery power and the light is dim, that may indicate a weak battery. When the battery is weak, the MTE may still function but demonstrate erratic behavior. That's a sign to replace the battery or use an AC-to-DC adapter.


The Delay Unit


You can test the operation of the delay unit without connecting an input. Use the same starting configuration as shown in the photo above, namely:

  • Power switch ON

  • Input selector switch on MIC (Note that when no input cable is connected to the MTE, this test of the delay unit only works with the input set to MIC.)

  • DELAY/10 switch on 0.5s

  • TIMEOUT on 0.01s position

  • All knobs turned to their halfway positions

  1. Press and release the TEST button. You should see the triggering indicator LED light momentarily. This indicates that the delay unit triggered.

  2. Turn the COARSE DELAY all the way clockwise. Press the TEST button. You'll notice a longer delay before the trigger indicator lights. Turning the FINE DELAY clockwise also increase the delay. However, you're not likely to notice this visually, since the FINE DELAY control provides about 0.05s of delay at the most.

  3. Flip the TIMEOUT to the 1s position and press TEST. The trigger indicator will remain lit for about a second. During this period of time, the delayed output of the delay unit is inactivated. When using a flash, setting a long timeout prevents multiple exposures. This comes in most useful when using the sound trigger. Loud sounds that last for a while or that produce echoes can set off the sound trigger repeatedly. Setting a long timeout provides time for the sound to decay before the flash can discharge a second time. When triggering a camera, a long timeout prevents the shutter from actuating repeatedly.

  4. Flip the TIMEOUT back to the 0.01s position, and flip the DELAY/10 to the 0.05s position. When you press the TEST button, there will be no noticeable delay even with the COARSE DELAY turned all the way clockwise. This is because all delays are divided by 10 from the original position. This is useful when you need particularly fine control of the delay for events for which the maximum delay needed is less than about 0.05s.

  5. Now flip DELAY/10 back to the 0.5s position. Using the appropriate trigger cable for your flash unit, connect the FLASH DELAYED output jack of the MTE to your flash unit. Turn on your flash. When you run a finger through the photogate or push the TEST button, the flash should discharge.

The above functions will work the same when you have an input cable connected. That connection will be described next.


The Photogate


With the MTE turned off, insert the 3.5mm plug of the interrupter photogate cable into the PG jack. Be sure to push the plug in all the way; otherwise, the photogate won't work. Flip the input selector to PG and make sure the PG SENS knob is turned to its halfway position. Turn the MTE on. The photogate alignment LED on the right side of the panel should light as soon as you turn on the MTE. This LED indicates that the photogate beam is unbroken. Now run a finger through the interrupter. The alignment indicator will go out, and the triggering indicator LED will momentarily light and the flash unit discharge after whatever delay you've dialed in.


Now turn off the MTE, remove the interrupter photogate cable, and insert the other photogate cable. Tape the emitter and detector to the table pointed at each other a few inches apart. Turn on the MTE. The alignment LED should come on. If it doesn't, check the alignment of the emitter and detector. If you wish, move one of them to the side to verify that the alignment LED responds correctly. Now turn the PG SENS knob clockwise until the alignment LED goes out. This happens when the sensitivity is set too high. In order to set the sensitivity at the highest it can be without going over the threshold, dial the knob back to the point where the LED comes back on. If you're running on battery power, the sensitivity may drift as the battery runs down. So if you have the sensitivity adjusted to the threshold, you may have to readjust it as the battery weakens. You also need to readjust the sensitivity when you change the separation of the emitter and detector. Whenever you position the emitter and detector for an experiment, be sure to anchor them as rigidly in place as possible in order to maintain alignment as well as the sensitivity adjustment.


Turn off the MTE and disconnect the photogate cable. Leave the flash connected for testing the sound trigger.


The Sound Trigger


Plug the microphone cable into the MIC jack and flip the input selector to MIC.Turn the SOUND SENS knob all the way clockwise, and set the TIMEOUT to 1s. Turn on the MTE. Snap your fingers or tap the microphone. The triggering indicator LED should light and the flash discharge the same as in your tests of the delay unit and photogate. With the TIMEOUT set to 1s, the flash will remain inactive for about a second. This is the typical TIMEOUT setting to use with the sound trigger in order to avoid multiple images from repeated triggering of a flash. You may use a TIMEOUT of 0.01s if you wish. With some flash units, you may find the flash triggers multiple times for a single triggering event. If that's the case, change the TIMEOUT back to 1s.


You can also trigger a flash using the direct output of the sound trigger, but first flip the input selector to PG. This disconnects the sound trigger output from the delay unit input. This is important if you're using a flash unit that has high-voltage (>80 V) terminals, as the flash can burn out the 556 timer otherwise. Now move the trigger cable to the ST OUT jack. Since this output of the sound trigger bypasses the delay unit, the sound trigger is in its most responsive state.


If you want to adjust the sensitivity of the sound trigger, do the following. Turn the SOUND SENS knob counterclockwise until the flash will no longer discharge. The reason that the flash can't discharge at or beyond this point is because the sound trigger is holding the flash in an on state. Turn the SOUND SENS knob clockwise just enough so that you can discharge the flash again. This adjusts the sound trigger for maximum sensitivity. If you wish to have less sensitivity, turn the knob further clockwise. Note that coupling the sound trigger with the delay unit will cause the sensitivity to change. You may have to make an adjustment if have the sensitivity adjusted to the maximum. If the greatest sensitivity isn't a requirement, just leave the knob turned all the way clockwise.


Turn off the MTE and disconnect the microphone.


The External Input


The external input jack can be used to connect other triggers to the delay unit of the MTE. When a 3.5mm mono plug is inserted into EXT INPUT, both the photogate and sound trigger circuits are internally disconnected from the delay unit. You can connect as an external input any trigger that produces a short circuit as an output. This describes all trigger circuits as well as a simple contact trigger such as the one shown here. In order to see how this input works, plug the external input cable into the MTE. Turn on the MTE and simply touch together the two bare wires at the end of the external input cable. (If you haven't prepared a cable, you can unscrew the plastic jacket from the 3.5mm mono plug that comes with the MTE and jump a wire across the contacts.) The delay unit will operate the same as if using the internal sound trigger or photogate.


You can also trigger the MTE externally from either the instant or delayed output of another delay unit. This means you can chain delay units for the purpose of triggering multiple flash units.


In the event that you want to plug an RCA-type cable into the external input jack, you can use an adapter such as the one shown in the last row of the table above.


Triggering a Camera with the Camera Opto-Switch


Important: Don't connect a camera shutter directly to either of the CAM outputs. You must use a Camera Opto-Switch with these outputs.


In order to trigger a camera, you'll need a Camera Opto-Switch and the associated cable. Connect the Opto-Switch according to the instructions for that unit. Connect the trigger cable of the Opto-Switch to either the CAM INSTANT or CAM DELAYED output jack of the MTE. You can then trigger your camera the same as you would a flash unit by using the TEST button, a photogate, sound trigger, or an external trigger.


Note that the ST OUT output cannot be used with the Camera Opto-Switch.


Using the Opto-Switch to Trigger a Flash Unit


The Camera Opto-Switch can be used to trigger many flash units as well as cameras. This makes it possible to trigger two flash units essentially simultaneously. You could connect one flash to the FLASH DELAYED output jack and a second flash through an Opto-Switch to the CAM DELAYED output. While there may a small time difference between the discharge of the two units, this will not be noticeable except for particularly high-speed events.


A requirement of triggering a flash unit using the Opto-Switch is that the flash unit may have no more than 80 V across its terminals. Higher voltages may burn out the optoisolator in the Opto-Switch. The requirement of having less than 80 V across the flash terminals is met by virtually all modern flash units. Older units, such as Vivitar 283s manufactured before 1984, have a few hundred volts across the terminals, but units manufactured after that time have only 10 V.


In order to trigger a flash unit with the Opto-Switch, you'll need to convert the CAM jack of the Opto-Switch to the RCA type so that it will accept a flash trigger cable. The adapter shown in the bottom row of the table above will work for this. Assuming you have the adapter in place, do the following:

  • Connect the trigger cable of the Opto-Switch from the TRIG input of the Opto-Switch to either of the CAM INSTANT or CAM DELAYED outputs of the MTE.

  • Connect the flash trigger cable from the CAM jack of the Opto-Switch to the flash unit.

  • Flip the Shutter switch on the Opto-Switch box to ON. (The FOCUS switch isn't used in this application.) You can then trigger the flash using the TEST button, photogate, sound, or external triggers.

Using Wireless Transmitters


You can use the MTE to trigger a wireless transmitter in order to discharge a remote flash connected to a wireless receiver. There are two ways to connect the transmitter to the MTE.


Important: Don't connect a wireless controller directly to either of the CAM outputs. You must use a Camera Opto-Switch with these outputs.


Method 1. Connect the ST OUT or FLASH DELAYED output of the MTE to the input of the wireless transmitter. The cord needed for this will depend on the transmitter. As an example, the PocketWizard Plus II can be triggered either through a 3.5mm phone jack or a hot shoe. In that case, you could use the RCA to flash foot adapter shown in the table above. Alternatively, you could prepare a cable with a male RCA plug on one end and a male 3.5mm mono plug on the other.


Method 2. Connect the CAM INSTANT or CAM DELAYED output of the MTE to the TRIG jack of a Camera Opto-Switch. Then connect the CAM jack of the Opto-Switch to the wireless transmitter. You could use the adapter shown in the last row of the table above to convert the 3.5mm CAM jack to an RCA jack. Then you could use the RCA to flash foot adapter to connect to the wireless transmitter.


Reported Issues


We provide here information on issues that have been reported when using the MTE with particular flash units.


Vivitar 283: We mentioned previously that when using the sound trigger with the delayed output, the Vivitar 283 may flash multiple times for a single triggering event. If this happens, setting the Timeout to 1s should solve the problem.


Sigma EF-500 DG Super and EF-530 DG Super: The flash must be set for slave mode in order to be triggered from the hot shoe. When the timeout is set for 1s, the flash goes off repeatedly for a single triggering event when using any input. Setting the Timeout to 0.01s solves the problem.


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