Monday, May 18, 2015

Filament LED Long Term Test

There has been much speculation on the service life of these filament LEDs.  Sounds like a good topic to study so I bought one and have been running it 24/7 while mapping out the light output.

At the ~600 hour mark (1 month) I am now getting a sense of the life time of the bulb.

Tuesday, May 12, 2015

BMP180 Barometric Pressure Sensor Extereme Teardown

A much more challenging tear down.  The BMP180 is a pressure+temperature sensor all in a neat little package with a digital interface.  As seems to be the case these days support is excellent for the Arduino platform with a robust library ready for use.

The package looks like a metal - can oscillator... with one big difference: a hole on top!

The top looks like it's simply soldered to the substrate... but no matter how heat I applied it stayed stuck.  An area worthy of further study.

However, as always, acid de-encapsulation worked here and two pieces of silicon were extracted.  One is a pressure sensor, the other a micro controller with I presume a temp sensor.

The die size is at the limit of my microscope.... might be time to get a metallurgical one...

Wednesday, April 29, 2015

What's Inside: Temperature and Humidity Sensor

A part of  a "big buy"... well, OK, $20.00 worth of parts from ebay.

So many just excellent sensors are now available for such tiny amount of money.

This sensor is a really good example... it measures two parameters and presents the data on a serial one-wire interface. All of the complex sensor characterization and trimming is neatly stored inside a micro-controller that's wire-bonded to the back of a small circuit board.   30 years ago this controller would have probably made a pretty good CPU section for a home computer... now it just disappears into sensor assembly.

What was once remarkable on it's own now just becomes a bit actor in the wider technical field... makes one appreciate just how many small CPUs are now part of every day things...

Philips "Basic Bulb" LED: End of the Race to the Bottom

Probably about as cheap as a bulb as possible without sacrificing the non-negotiable (UL/CSA safety), light quality.

By not achieving a high power factor and not enabling dimming the designers were able to jettison tons of cost.  Sometimes these savings are really subtle, for example, when dimming a bulb it often hums due to magneto-restriction in the transformer cores. This is often overcome by adding potting compound to dampen and silence the bulb which drives cost.

Light pattern surprisingly good, efficacy very good.  One can see a place for such a light bulb in the market.

Tuesday, April 14, 2015

Solais LR30 LED Bulb Teardown: Quality

An interesting bulb which is targeted to a much higher end market.... refreshing change after looking at all of those bulbs chasing the lowest possible initial price.

I should buy a non-fanned LR30 from a big-box store and see what the led temp rise difference is... I suspect it's huge.  One can move an amazing amount of energy with even a small fan.

Tuesday, April 7, 2015

Joule Meter: Precise Energy Measurements of an Electronic Circuit

I needed to measure the exact energy draw of a circuit.  Since energy is measured in Joules, a joule meter.

I could not find anything quite like this in the market... the closest I could find were some watt-hour meters but they still had very poor resolution.

So I made my own.  Arduino based with some custom circuits.  Video, below.  Sketch used on the arduino below that:

Monday, March 9, 2015

Philips "Warm Glow" LED Bulb: Tune able Color Temperature

One of the drawbacks of an LED is that it will produce the exact same color (measured in Kelvins) at all brightness levels .... problematic when one desires a warmer, more cozy dimmed light.

This bulb brims with innovation to create that effect.  A very neat bit of engineering!