Archive for category tools
Photos of mechanical, front panel design
Posted by Michael Beach in how-to, parts, tools, vendors on October 28th, 2009
Portable electronic instruments. These photos show knobs, nuts, knurled, and know-how (Pete’s). These are working photos of our differential amplifier project. They show how we can get the electrical boards to line up with the mechanical connectors, and controls. And how an extra layer of plexi can be used to add a nice finish, and provide a solution to the incompatible height of the controls (note the nut is recessed by the plexi).
overall view of assembly, showing how it slides into the case
close up of the BNC connectors
BNC aignment of pcb, fron panel, and mounting BNC panel
cardboard pcb mock-up, with the real board and assembly behind it - we like to make quick mock ups as we design, just to check everything is going well
Detail of the plexi layer used to 'bury' the nut needed to hold the front panel control. The plexi is an additional part, but the incompatible heights of the controls meant there had to be some way to accomodate all these part variations.
Light uniformity testing
Posted by Michael Beach in how-to, metrology, optics, photo, prototype, tech notes, tools on July 15th, 2009
For both a clinical test microscope, and a home theater HDTV projection display, the light from the source must be quite uniform.
To test some non-imaging illumination optics, we set up our digital camera, and wrestled with the RAW data files from the camera. Most cameras have some ability to ’see’ infra-red, so we can also test the pattern from the remote control output, or for other purposes.
Here we test the light uniformity of an LED source using a digital camera and some Thor Labs mounts.
These graphs were generated by ImageJ from the RAW data files of the Nikon D1x camera.
Custom front panels
Posted by Michael Beach in how-to, parts, prototype, tech notes, tools, vendors on July 14th, 2009
Here’s a vendor we recommend, and a photo of some parts they made for us.
When you make one or 10 of something it can be difficult to make it look ‘real’, that is, to make it look finished. Sometimes the Dymo-Marker labels are OK, say in a sci-fi movie, for your Custom Flux-Capacitor. But other times, you want the prototype to look clean.
We have enjoyed using the services of FrontPanelExpress to make some custom front panels for our projects. They provide free software, that’s simple and easy to use, and you upload the files to their on line ordering … and you get great parts back. A variety of anodized aluminum options and thicknesses.
http://www.frontpanelexpress.com/
They will engrave text, add paint colors into the text -makes a very nice professional looking prototype or short run of parts.
Just imagine – they can easily make a D-shaped hole for the BNC – so it won’t UNSCREW and FALL OUT !!! That alone is worth the price of admission. I can’t find my D-shaped drill bit …
They can do a lot of things that are a pain to do by hand – countersink holes, nice RS-232 type D-cutouts, square holes, etc. Check out their site for some examples.
We also made a Plexiglass panel – this allows us to compensate for the very annoying differences in height of the switches and knobs – and it allows simple paper graphics to be protected. We also considered making a glowing logo, but have not yet done that.
Image Analysis
Posted by Michael Beach in metrology, optics, tools on June 29th, 2009
Lately we’ve been able to use our digital camera to perform some nice measurements, through the help of a program called ImageJ.
It’s free, was developed at NIH, is open-source, it has a ton of features and plug-ins, and you can write scripting macros, etc etc. It was developed so that the scientific community would have an open standard to process images. (Without an open standard for image number crunching, there’s no good way to independently reproduce an experiment that makes heavy use of images and image processing.)
You can read about it here at Wikipedia:
link to wiki entry for ImageJ program
http://en.wikipedia.org/wiki/ImageJ
It’s available here:
http://rsbweb.nih.gov/ij/
We were turned onto this image analysis program by a couple of our clients. We recommend it. Today the cool thing was to separate the RGB channels, and allow us to ’see’ an IR LED without being confused by the camera’s ‘grey scale’ clipping algorithm. Very nice.
attenuators, connectors, etc.
Posted by Michael Beach in how-to, parts, prototype, tech notes, tools, vendors on March 13th, 2009
Here’s where to get quality attenuators and connectors
Testing any high gain low noise amplifier requires a nice clean attenuator.
You need to drop the level of your function generator,
or that x1000 gain amp would need to supply 100 V output.
Pasternack Enterprisese sells a nice 30dB atten for about $42.
Their part number is PE7000-30.
If you put 2 of these in series, you have about x1000 attenuation.
(These assume a 50 Ohm load, so buy one of those too).
Here’s a link to their website:
http://www.pasternack.com/