Category Archives: Electronics

Mechanically etching PCB boards

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Process to get PCB boards made.

– Design in Eagle, and export from the CAM module in Eagle layers 16, 17, 18, 20, as GERBER_RS274X
– Also export layers 44 and 45  as EXCELLON
– Import gerber file and excellon fine in CircuitCam
– Isolate as required (using only small and standard tools), and batch export DXF ;this outputs 4 files (small tool path DXF, Standard tool path DXF, Drill DXF and border DXF)
– Import DXF files in CNC USB Controller software, and export “Toolpath to G-code”
– Each DXF file will have a .nc file to be cut with the appropriate tool.

AF Assistant v3.2 development

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Work has been progressing on a newer version of the AF Assistant. The next incremental version (v3.2) will be made using surface mount components, and extra safety precautions have been added to protect the camera from any unwanted electrical signals.
Both inputs from the camera are isolated using buffers, and the ground is protected against reverse voltage.

Testing on this new design should start soon, and once complete all new AF Assistants will be built using this process.

 

AF Assistant news

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I’ve decided to use the version 3.x set of identifiers for my AF Assistant as the one battery, line laser based system. Plan is to also develop a near IR version of this tool, and that will be version 4.x.
So for now all current development of the one battery, line laser model will fall under the 3.x naming designation.

Installing EagleCAD 6.1.0 on OpenSuse 12.1 64bit

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First try I did not get eagle to install in a 64bit linux OS.
Gave up and installed it on a Win7 VM instead so I could start using it.

Tried again today, and figured it out.

The error I was getting initially was

/tmp/eagle-setup.16234/eagle-6.1.0/bin/eagle: error while loading shared libraries: libjpeg.so.8: cannot open shared object file: No such file or directory

The reason this message came up was because I needed to have the 32bit version of libjpeg-8 library installed. By default I guess opensuse only installs the 64bit version (since I’m running a 64bit OS).

Just had to go in the Yast -> Package Manager and search for libjpeg, and select the 32bit version of the libjpeg-8 libraries.

PB10 Prototyping Board Review

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Prototyping boards were never at the top of my priority list when spending money. The cheapest thing I could find would suffice. The most I had previously spent on a prototyping board was seven or eight dollars from local electronics surplus stores. They did the job.

However in the fall of 2011 I picked up a $24 prototyping board (PB-10 by Global Specialities  ) from Newark since my old board was giving me hassles. The problem I started having with the cheapo prototyping boards was that wires would get stuck in the hole, and would require a lot of force to yank out, and some paths just totally stopped working.

The PB-10 is a great. The insertion force is minimal, nothing gets snagged in the holes, and the battery posts are fantastic. No more battery contacts pulled out and accidentally whipped across expensive components.

Have built a couple of projects on this board, and I don’t think I will cheap out again on a prototyping board.
It’s the little things that make a development project work smoothly.

AF assistant v3.1

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UPDATE: Work has indeed started on the (near) IR version of this tool. Details on the AF Assistant IR 1.0 (in early development stages) can be found here.

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Right from the get go, i wasn’t the happiest with the v3.0 design (see v3.0 link for details of why I built this, and previous version history) of the AF assistant. The main concern i had with it was the sloppiness of the case, and the extra cables that were required (which some of you commented about on the hack-a-day post).
So I did some searching around at local electronics shops and came across a small case that has a battery compartment for one AA battery. Digikey also sells a version of the case in black, which I will grab for the next upgrade. Much sleeker then cream colored on a black camera, though more expensive then the $0.25 I paid for the cream colored cases.

About the same time, i received an order from DealExtreme for some line lasers i had ordered some time ago. So I put together a circuit based on the v3.0 design (plugs in the side of the camera in the remote trigger port) and i have added a dc-dc boost voltage regulator that takes any voltage (0.7volts and higher) and turns it into a constant 3.3volts (based on suggestions from the hack-a-day post comments). This is perfect since that means that regardless of what battery i use, (1.5v alkaline or 1.2v NiMH rechargeable battery) i can get a constant voltage to drive the line laser. Continue reading →

AF assist tool v3.0 – complete

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Updated version available here. Version 3.1 is complete.

It’s done!

Version 3.0 of my AF assist tool is complete.

Taking a step back, I should explain why I needed this tool.There are really 2 reasons I built this:

1. When photographing concerts or clubs, or any other venue where light is at a premium, the AF sensor in the camera can only do so much to give accurate focus. I am using off-camera flashes most of the time now so I am not relying on the ambient light to paint my scene; that’s what the flashes are for, but I still need to focus. No remote flash trigger to date has had a AF assist light built into it. I use a Pocket Wizard Mini TT1 trigger and Flex TT5 receivers to trigger my flashes, along with an AC3 zone controller (which allows power control of 3 flash groups). So with a flash trigger in the camera’s hotshoe I loose my AF assist light, which normally I would get from a regular flash.

2. DSLR cameras (that I’ve looked at) don’t do AF assist in AI-Servo mode. They don’t allow you to track a subject in the dark, by continuously adding the light from the AF assist lamp on flashes to help the AF sensor in the camera continuously maintain focus. You get One-Shot focus, and once focus has been acquired, the light goes of. But if I want to track a singer as the move on a stage, like one would track a moving person or a race car during the day, you’re stuck. You can’t. This AF assist solves that problem but allowing full control of the AF assist light to be projected as long as you’re focusing (focusing is done by 1/2 pressing the shutter). Continue reading →

AF Assist tool v3.0 – schematic

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I think I have a schematic I am happy with to drive either an LED or laser module.

The 3.3V from the camera comes from the Remote Shutter connection on the side of the camera. One of the pins puts out 3.3v continuously, and when the shutter button is 1/2 pressed, the 3.3v drops to 0v. The op-amp is a buffer to separate the camera from the circuit, and to provide no load on the camera connection.

The pnp transistor turns on when the voltage is 0Volts at the base, and turns off when the voltage starts to increase. The potentiometer injects a little voltage into the transistor allowing for some control of the brightness.

Will build this on the weekend and will comment on how well it worked out.

The op-amp is a low power op-amp (NJU7016D) which will work down to 1V. To get a constant 3V supply to the circuit I’ll use a step up DC-DC converter (893-1150-1) which will take anything from 2-6V and convert it to 3V. So I can use rechargable Ni-MH batteries without a problem. I suppose I could use Ni-MH batteries but the light output will not be as bright. Will need to test this.

Continue reading →