docmaas wrote:
i'm interested.
mike
CT Don wrote:
Boris Starosta wrote:
After some months hiatus, I disassembled the top plate of the Sigma camera, hoping to find electrical contacts with the shutter switch. Alas, no better contacts could be found, than I'd already found earlier. The switch itself is inaccessible due to the circular race of contacts surrounding it, which make it impossible to run a wire directly to the switch.
I brought the piece to my local camera professional, who was unable to help. As to my suggestion of soldering to the contacts showing resistance values, all he could do was shake his head.
So that's it for the Sigma Merrill cameras: there's absolutely, positively no way to wire in an electrical remote release, and therewith no way to electrically synchronize a release of the shutters of two cameras.
I have this idea that maybe there's a way to fire the camera through the USB port, but that would require hacking the camera OS, a task for advanced black hats which I haven't got!
This is unfortunate! This is a very affordable and handy camera that makes beautiful images. Alas, without electric release, this camera will remain of very limited utility for my stereoscopic work... I'll be looking for a replacement.
If you are still interested, I found a way to add wired remote:
Sigma Merrill Wired Remote
Alright, then -
Disclaimer: I didn't photograph my work as i did it, so I'll use photos from this forum to illustrate, annotating them as necessary. I may be modding another camera soon, in which case I'll update this post with my own photos.
First, a little theory of operation: Under the shutter button, are 2 switches. Actually, it's one unit with two independent switches inside, one on top the other (the Foveon of push button switches ;-)). When you press the button fully, the top switch closes first and then the bottom switch closes. The top switch tells the camera to focus. The bottom switch tells it to fire. A half press only causes the camera to focus. The common of each switch is connected to ground, so when the button is pressed, ground is applied to the appropriate circuitry to cause the camera to focus or to focus and fire. The photo below shows the switch and pass throughs for the focus and shutter release signals. Note that the switch is inside the contacts for the rotary dial that surrounds the shutter button. Wipers from the dial (when it's in place above the switch) ride on these contacts. The dial can be rotated continuously in either direction, preventing any wires connected on that side from exiting.
Shutter Switch
The first steps are to remove the back cover, two circuit boards, battery housing, and top plate, following the excellent instruction in this post: https://www.dpreview.com/forums/thread/3998582.
It isn't necessary to disassemble the back plate any further after it is out of the camera.
My method was to find the easiest place to attach 2 fine wires to the focus and fire sides of the switch and to bring them, and a ground wire, out of the camera body near the USB connector. I used wire wrap wire, which is insulated 30AWG solid wire.
Because the shutter switch is completely surrounded by the rotary switch, there is no way to attach wires directly to the switch and bring them out, without removing the rotary switch. From the photo above, it's obvious that the runs pass through the circuit board and continue on the other side. It's just a matter of finding out where the traces from the switch go after they pass through the board.
Here are the spots:
Focus and Trip Soldering Points
And, from a different angle:
Focus and Trip Soldering Points
I don't actually know (or care) what that component is, but I suspect it contains a pair of resistors that pull the voltage on the switches up, when the switches aren't actuated.
I soldered a wire to each of these points and routed them out of the camera. I followed the path of the microphone wires, then doubled back to bring them out near the USB connector, but there are other routes. In fact, I considered using the speaker wires to connect to the board and simply replacing the speaker with a connector, but for my purposes it was better to come out the other side.
Caveat - if you are going to duplicate this, you will need a very small soldering iron tip, very thin solder, a steady hand, and fine soldering skills.
My technique was to apply a small amount of solder to the leads of the component where I was going to attach the wires and also to the wires. Then, to position a wire against the lead of the component and touch the soldering iron to the pair. I soldered the wires perpendicular to the circuit board so as not to risk shorting a wire to any other component on the board.
For the ground wire, I chose to reinstall everything except the back cover, then pick up ground from circuit board #1. There are myriad spots that will work. I chose the one pointed out here:
Place to Solder a Ground Wire
I routed the 3 wires through the slot underneath the tab (next to the arrow) and out of the camera. Then, a filed a small notch in the back cover to accommodate the wires, put a small length of heat shrink tubing over the wires and replaced the back cover.
Reassembled
After testing that it worked by touching the ground wire to each of the others, I attached a 3-pin Molex connector and glued it to the USB/AV door.
Finished
Of course, you can use any connector of your choice. This one works best for my application, which is to install the camera in a hexacopter and fire it from an Arduino camera controller. I also attach an AV cable and transmit the video to a ground station.
Sigma AV on Ground Station
Thanks to all of you whose photos I re-used. I hope this is helpful.
-Don
