LED Holiday Lights

Relative merits of LED holiday lights by Katherine Tweed at Greentech.
http://www.greentechmedia.com/articles/read/should-clark-griswold-switched-to-led-christmas-lights1

Comments:

Look for the warm white LED holiday lights sets - a bit less efficient, but they give a better feel.

Buy light sets for next year after the season is over. The post-holiday sales can beat year-to-year price drops by as much as three-to-one. But this is as valid for incandescent sets as for LED sets.

Probably should consider a life cycle analysis. A holiday light set (any type) recovered for reuse (craigslist?) might have better cradle-to-grave economics.

This brings up the “coffee cup life cycle analysis”
http://alumni.stanford.edu/get/page/magazine/article/?article_id=28765
You can search for and see endless debate and nuances. But one good conceptual summation, after materials, washing, kilns and so forth, is…

If you reuse a mug (or whatever) which was headed for waste stream, conservation is served. It is not clear cut. Older cars and air conditioners may be better off recycled. And market economics may not be well served by reuse.

Ultracapacitor Supercapacitor Tools

Popular Science DIY supercap screwdriver (and useful links therein)
http://www.popsci.com/diy/article/2008-02/make-instant-charge-screwdriver

Also useful links herein... see tools, portable use section
http://en.wikipedia.org/wiki/Electric_double-layer_capacitor

Coleman FlashCell - came and went...
http://www.popularmechanics.com/technology/gadgets/4223118

Supercapacitor screwdriver comes up as a half baked idea...
http://www.halfbakery.com/idea/Supercapacitor_20Cordless_20Screwdriver

There are problems:

• Low voltages
• Series cell balancing issues
• Brief (millisecond) blips in charging voltage can do damage
• Linear capacity means energy in under 1V range goes forever unused/wasted
• Fast self discharge

Power over Ethernet for Lighting - LEDs

Have ongoing work interest in 802.3af and 802.3at Power over Ethernet
http://en.wikipedia.org/wiki/Power_over_Ethernet
for non-classical applications (not VOIP – voice, video). Mostly interested in sensors, actuators and protocol/serial conversions via 802.3af. Communications drives these applications.

What if we drove further and looked at how far 10W could get one in a real physical application with an eye to communications. Lock strikes, dampers, valves, keypads and small displays get into this realm. What if the deliverable was literally power? What could be useful at 10W? The answer is that LED lighting technology is now practical at this level.
http://en.wikipedia.org/wiki/LED_lamp
http://albertputnam.blogspot.com/2012/10/led-lighting-update.html

Scenario for LED lighting:
-Space (house/suite) wired for Cat5e or Cat6. (as-built or retrofit).
-802.3af managed gigabit switches installed (for use with VOIP as starter) like Dlink DGS-1210-10P.
-Unused sockets get 802.3af LED lamps (prototype – Trendnet TPE-112GS – with a 5W USB desk lamp).
-Local and (intelligent switch) managed control of the LED lights.
-UPS backup of 802.3af injection, and thus lights, where needed.

This involves only safe low voltage wiring. International acceptance/use/deploy possible.

Build 5-10W LED lamp with RJ45 connector and module like Silvertel Ag9600/Ag9700 series or similar (Ag9605? Ag9603?). Interesting if one could get 802.3af direct to LED driver (current) circuit.

LED Lighting - Update

Posted on LED lighting in last few days of 2011.
http://albertputnam.blogspot.com/2011/12/led-lighting.html
Here is a nice roundup article from Greentech Media, Jeff St. John.
http://www.greentechmedia.com/articles/read/LED-Roundup-Redwood-Systems-Lumenergi-IKEA-and-the-GSA

Smart lighting comes up... and always seems to go down the wireless path. Why not think about where the power comes from differently? What if power came with your communications? LEDs need much less power, and what if you had a standard way of delivering low power via the network?

Presto: 802.3af and 802.3at Power over Ethernet (PoE).
http://en.wikipedia.org/wiki/Power_over_Ethernet

Will discuss more about PoE and LEDs in subsequent posts.

Somerville Maker Faire - 2012-OCT-13

Somerville Maker Faire - on Saturday October 13, 2012 - sadly cannot make it - visiting family.
http://www.makerfairesomerville.com/

Took a look at hackerspaces list
http://hackerspaces.org/wiki/Boston
and was intrigued by Artisan's Asylum.
http://hackerspaces.org/wiki/Artisan%27s_Asylum
http://artisansasylum.com/

Saw them mentioned in the Boston Phoenix 10.12.12 p14
http://thephoenix.com/Boston/life/145599-robot-invasion/

Which led to
http://www.makerfairesomerville.com/

ESC Boston 2012 - Design East

Attended ESC Boston 2012. Now called Design East.
http://east.ubmdesign.com/
http://events.ubm.com/event/1713/esc-boston-embedded-systems-conference
http://en.wikipedia.org/wiki/Embedded_Systems_Conference
http://en.wikipedia.org/wiki/Embedded_Systems_Conference#ESC_Boston

Glad to see a few of the familiar faces and ask them about new trends in the industry.
Lantronix http://www.lantronix.com/ xPico
Microchip http://www.microchip.com/ Metering and Wifi
Various systems based on ARM processors
http://en.wikipedia.org/wiki/ARM_architecture
Our mantra is "more RAM". Even if just for one sensor and minimal OS features - still want DB and security - 256M minimum.

Power over Ethernet 802.3af and 802.3at.
http://en.wikipedia.org/wiki/Power_over_Ethernet
http://www.silvertel.com/

Should give positive mention to Symmetry http://www.symmetryelectronics.com/  for hosting Lantronix, Silvertel and others.

Looked at Wurth Ethernet 802.3af magnetics with LED. http://www.we-online.com/web/en/wuerth_elektronik/start.php

Toradex - USB sensors and ARM processors. http://www.toradex.com/

Interesting talk on Internet of Things http://en.wikipedia.org/wiki/Internet_of_Things
by Micheal Anderson of PTR http://www.theptrgroup.com/

Blogged before of Google Goggles to read meters. Visited Vision Components http://www.vision-components.com/en/  and looked at their smart cameras.

RS485 Rule of Thumb: N x L x kB x P < 485

RS485 rule of thumb: N x L x kB x P < 485
This is for RS485 bus architectures like those for Modbus RTU, BACnet MSTP, Johnson Controls N2 and so forth.

N x L x kB x P < 485

Where

N = the number of quarter (or less) load devices. If using older full load devices then consider each device as four devices. For example three quarter load devices plus three full load devices and two sixteenth load devices would mean N = 3 + 12 + 2.

L = the length of the line in 100m multiples. For example 1000m (1000yards) means L=10.

kB = the speed in kBaud. For example 9600 baud would be kB=10

P = The problem factor. P is a number which is usually unity when all the line characteristics are well conditioned. Double it for poor biasing. Double it for poor termination. Double it again if runs are close to motors or transformers. Double it for improper capacitance. Double it for poor twisting. Double it for ground faults like poor/weak or multiple grounding.

So a 100m line with four quarter loads running at 20kB with a couple of problems P=4 (320) is probably okay. But a 1000m line with ten quarter loads running at 10kB with P=1 (1000) is likely problematic.

[Updated 2012.09.19 by rescaling L to make the arbitrary number '485' easier to remember.]