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Mic Mono/Stereo Adapter, PCB version…

A previous post detailed an adapter that could combine two mono mics with 1/8″ jacks for use with a camcorder, as well as a headphone splitter so that two headphones can be used with a single jack on a camcorder.

This adapter was used to record a video.  A Rode VideoMic on a boom pole and an Audio Technica ATR-3350 clipped on the talent were used together with the mic combiner part of this design. The boom pole operator and the camera operator both had headphones on using the splitter part.

A board has now been designed that can function as either a mono/stereo combiner or headphone splitter depending on how the jumpers are configured. The board is set up so that 0.1″ headers can be used with computer type jumper blocks but the configuration can be soldered in place as well.

Here is the schematic:

monostereo-sch

The Mic Adapter configuration has three modes of operation:

  1. Two mono mics are combined from jacks J1 and J2 to J5.
  2. A stereo mic can be plugged into J1 with stereo output at J5.
  3. A single mono mic can be plugged into J2 and appears as a stereo mic at J5.

In the headphone configuration, a stereo source may plugged into any jack and two headphones into the remaining two jacks. It should be noted that in this configuration, J1 always needs to have something plugged in to keep the left and right channels from being shorted together. (This could have been avoided but it would have required extra jumper points. Boards made with the existing design can have the trace cut at J1 if this is a concern.)

The layout is here:

monostereo-brd

Boards may be ordered at OSH Park. It uses these jacks (from Digikey).

The board offers no strain relief, so care must be taken to keep the jacks from being pulled off the board.

Posted by by david

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Yet another little board…

I successfully made and tested another board based on the QFN32 version of the KL25Z device, the smallest package it comes in. It’s a pain to solder down because the PCB pads need to be pre-wet with solder, a generous helping of flux applied, aligned via eye-ball, and then hot air gently blown so as to melt and reflow the solder. A soldering iron top is too fat to get down into the crevasse to solder.

microKL25Z

The schematic of the board is here:

MicroKL25Z-DIP-v1-board

The Eagle files and fabrication output are zipped up here: MicroKL25Z-DIP

Three boards may be ordered for $4.25 here: http://oshpark.com/shared_projects/MsCRJIem

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New board for prototyping the functions of the Swiss Photoknife…

The boards from the previous post finally arrived.

Here’s a photo of the board with the KL25Z mounted along with a few passive components to make it work. The five wires on the left go over to a FRDM-KL25Z board, which supplies power and permits programming the device.

IMG_20131016_110802

All the pins wiggle as they should, so now the various functions of the Swiss Photoknife can be tested before rolling them all up into a single kitchen sink board…

 

[UPDATE 10/22/2013] This board has been shared and can be ordered via OSH Park at a slightly higher cost than Seeed Studio.

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More Printed Circuit boards…

I became very excited after having received a Freescale smart car kit. Although I have yet to get the camera mounted and make it follow a line, I have been playing with the microcontroller board that came with it, and the online IDE/compiler tool chain for it.

So excited that I just had to build my own boards for it…

There are various boards out there for doing various photographic control functions but there are no one-does-nearly-all, kitchen-sin, Swiss army knife, hackable photo controllers to be had. The boards I made will be the test beds for prototyping the various functions I intend to include on a multipurpose photo control board. More on that later as things progress.

The device at the heart of these proto boards is the Freescale Kinetis KL25Z in the 64-pin QFP package. There is a header for a Nordic Semiconductor nRF224L01+ 2.4GHz data transceiver module that’s are commonly available on eBay. There’s also a header for a Nokia 5110 type LCD display and for programming. All the pins are brought out to a hole and a little general purpose prototype area. Total cost for ten boards measuring 50mm x 50mm was $15, where $5 of it was for shipping (the vendor was Seeed Studio, for those interested; they have extremely good prices…).

I received an email this morning that the boards have been shipped back to me. Now the excruciating wait for them to arrive…

Below are the schematic and layout.

KL25Z-64QFP-sch

KL25Z-64QFP-brd

Here are the Eagle and Gerber files: MiniKL25Z-64QFP

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Normans In Action: Another Art Shoot

Here are some behind the scenes photos from the latest art shoot.

DFAC-10-BTS-001

 

In the foreground, there are two PVC panels, each clamped directly to a light stand. Each panel is illuminated by two Norman LH-2 heads connected through a Y cable by a Norman 200B power pack. All the flat artwork was photographed leaning against the podium.

The sculptures were photographed in a light tent assembled from PVC panel pieces (four straight lengths and four lengths with elbows at each end). A piece of black velvety material hangs from the back so as to appear as an infinite black background. This was illuminated by AC powered slave strobes, but not all three were used for every photo – sometimes fewer were used, depending on the piece. They were alo moved around to change where they were aimed.

DFAC-10-BTS-002

There were two very heavy sculptures that had to be photographed in place out in the hall, so one panel was used as a reflector (the one on the left) and the other was used as the diffuse light source.

DFAC-10-BTS-003

And here is a final image of the other sculpture piece out in the hall way:

DFAC-10-BTS-004

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