DIY DVX100 Zoom Control with Record Start/stop
by Jarred Land
All thumbnails on this page are heavily compressed for speed, Click images to enlarge uncompressed.

Caution - As with any DIY project, there is a chance to screw your camera up and burn down the house at the same time. If you feel at all uncomfortable doing this project, there are many professional Zoom Controllers available to purchase already made.

I decided to build this project after learning about the Cam input wiring a few months ago, and learning how simple it was compared to a LANC configuration. I was a little miffed because after learning the schematics I realized it was impossible (as far as I know) to control anything else like Focus through the cam control port. I went to Radioshack to pick up the parts only to find up here in Vancouver Radioshack doesn't sell electronic components anymore, you need to special order them. Go figure.

Anyways, lets begin.

Probably the simplest electronic device you will ever make in your life.


Parts list: Since I purchased these from RP electronics, I will include links to each item, they ship to Canada and the US, and their web site shows both currencies. Just click the Price to visit the link. Parts Express etc. may have similar parts.

Qty Description Price/Link US$
2.5mm Stereo Plug - Plastic, Black, strain relief
Plastic Enclosure 60 x 35 x 17mm
Momentary Switch, any will do
20k Linear Potentiometer*
Bicycle Tail Light for mounting clip
Spring Clamp Testing Cables (optional)
USB cable to be used for wiring
Push Knob, personal preference


* Purchased grab bag of 20 pots, contained 4x20k.

I was pretty lucky that RP had a "grab bag" of 20 different rated pots for less than 5 bucks. This allowed me to test multiple frequencies, and corrected my assumption that a 15k would be perfect. I found 20k to be the perfect match. The way the Zoom dial works is if the pot is in the middle, between about 8-12k, the zoom is stationary. Lower zooms out, higher zooms in. The speed of zoom is variable just like the rocker, in aprox. 3 speed steps each way. At around 2k and 18k respectively, the max zoom speed is initiated. You can use different rated pots and use resistors or wiring to get it down to 20k, but just using the right one is the easiest way to go.

The record button was pretty basic, whatever momentary on switch you feel partial too will work, and there is plenty to choose from If you try a button and it clicks when you press it, it wont work because that is a on/off switch.

Once you have everything, lay it out as you would wire it, and I recommend using alligator test clips to hook up the parts to make sure everything works.

When you are wiring the pot, it will have three terminals first hook it up to terminal 1 and 2 and the other end to the ground and exterior terminal on the mini plug. Plug it into the camera and see what happens. If your zoom is going the wrong way when you test it (such as turning left zooms in instead of out) then switch from pin 1 and 2 to pin 2 and 3 connected.

Do the same with the push button, doesn't matter which way you wire it as long as one terminal is on the ground on the plug.

Best thing before soldiering is to test your hookup to make sure everything works. Here we see the Pot switch hooked up, and confirmation via turning the camera on and "Yahh it works!"

Now to prepare the box. This is all personal preference, so see the photos below how I did mine.

Next step is to prepare the box for assembly, you need three holes, the smallest for the cable, the bottom for the Pot switch, and the large is for the Record button. Be sure to mill the edges of the holes to ensure a flat mounting surface for the switches.

Once you have the box ready, slip the wire through the box, mount the switched if needed at this point and solder them up. As a final touch I like to wrap the connections with electrical tape to help against shorts and corrosion.

Put everything in place in the box, and tighten the nuts that the switches came with. I also filled the thing up with the glue gun to make sure nothing moves around, and keeps the cable safe from jerks. You can instead tie a knot to create a cable stop. Or what the hell, do both.

Here Is the Zoom pot and Rec. button soldered and then Glue gunned into the box. Before soldiering, make sure you have all the cables routed through the holes and switches seated.

After you finish soldering the mini plug, test to make sure everything works, close the box, take a deep breath and go eat a cookie.

I found a solid way to mount the box to a tripod handle etc. Is with the use of a bicycle rear blinking light, I picked one up from the local dollar store for $2 and it came with a QR clamp that mounts to your tripod handle or whatever, and the light can clip into it, or you can use the light side to clip it onto clothing. I took the clip off the light (it is screwed on) and attached it to the box. Perfect fit.

The bike light clip had screws that we fixed to the top of the project box. Once assembled, Plug it in, turn on the camera, and cross your fingers :)

    That's it, that's all, see how easy that was! No you don't have to zoom and focus with one hand while you pan with the other.

To make this better, I would like to put a return spring in the knob so it defaults back to center, and maybe make a little rocker switch out of something and then turn the pot on its side to make a rocker type. I would probally need to use a different pot with a resistor to reduce the zoom swing. Any ideas?


I found a nice knurled aluminum knob that seems to work better. I also rotated the unit sideways, and it gives me a nice thumb roll for zooming.

Click here to discuss this in the forum : DIY Zoom Control

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