Wednesday, November 19, 2014

B&K PRECISION 9110 LAB POWER SUPPLY REVIEW

A viewer of my you tube channel asked about this power supply which I have had on my bench for a few years.  A short review video.  The 100W rating and up to 60V or up to 5A has proven to be a very useful range (most of my other supplies seem to always fall far short of 60V which had always been a problem).

The build quality was reasonable for the money paid (about $300).

The only knock on this supply is if it goes into current limited mode right after a power cycle... the control loop looks a bit loose and there is some over shoot.  Generally not a problem for the work I use it for as the voltage control on power-cycle is well controlled.


Tuesday, November 11, 2014

CREE 4 Flow LED Light Bulb Tear down and Review: race to the bottom, 2nd entrant

Very similar to the Philips Slim Style.  Appears to be a very cost effective bulb, but that required some compromises.  It will be interesting to see what level of market presentation bulbs like this will get... one can see where there is a place for them in the market.

Better bulbs can be had for not much more money.. however if they get tossed into a utility rebate scheme where they cost only a few $'s each I can see places where they could fit in (seldom used bulbs where light quality and noise performance is not paramount).


Wednesday, October 29, 2014

Openbeam: Rapid Mechanical Prototyping

Over the last few months I have had a few project on the go which required a mechanical aspect. I have been keen on trying out some OpenBeam (openbeamusa.com).  This kit can be easily purchased on Amazon in the States and at solarbotics.com in Canada.  The owner of the company writes a persuasive and interesting blog on running a business based on his expertise in mechanical engineering.

However metal fabrication is not an area where I am an expert..  After sifting through lots of Youtube videos, personal web pages and reading a few books I picked up enough knowledge to fabricate what I needed. This video is simply some of the techniques that I learned... perhaps of use for those also considering openbeam.



Thursday, October 23, 2014

Color LED Disco Light

A quirky ebay find.... designed for dance floors or parties.

The use of a rotating half globe of lenses and a strategic placement of three leds in a triangle enables a very complex light pattern... much more complex looking that one would expect from such a simple setup.

Tuesday, October 21, 2014

Philips B11 LED Candelabra Bulb Teardown

This bulb met an early demise after a lamp tipped over and the base broke off, a perfect opportunity to tear it down.

The light pipe shows lots of engineering!  It's an attractive-enough bulb, but I would expect that bulb like this  would tend towards the LED filaments over time as they look much better. Candelabra bulbs are often used in fixtures where appearance is paramount.




Monday, October 20, 2014

Removing non Re-workable Potting Compounds

Some electronics use potting compounds to protect the electronic components on the circuit board.  Unlike the LED bulbs that I have been tearing down, there is a whole class of potting compounds designed to be non re-workable.

I was reading a forum entry at eevblog.com where someone was wondering how to remove these compounds for reverse engineering purposes.  Suggestions ranged from strong acids to heat.

Since most potting compounds seem to be epoxies there is an attribute called the "glass transition  temperature" seemed like a promising avenue to exploit.. basically these materials turn from strong glass like substances to rubbery if you put enough heat onto them.  

It was an interesting application of material's property to solve a problem.  Lot's of dead ends on this one... a bunch of things I tried were not successful.

I am glad, however, that LED bulbs use different potting materials materials.  Removing these types of epoxies is not pleasant... a full-face respirator with an organic vapor cartridge was required.... and a full-blown lab-grade fume hood with a  scrubber is really required.


Thursday, October 9, 2014

Facto (Rona) LED Light Bulb Teardown

From one of Canada's largest hardware retail chains.  A good example of a house branded bulb and quite representative of a mid-range 2014 offering.

Envelope of the bulb is glass, not plastic.... found that out the hard way :)  .... hack saws and glass don't mix.

The emitter construction is, yet again, different than other bulbs.  It's remarkable the number of implementation that can be found out there.