Thinking Outside The Box

On 14/03/12 15:43, Peter Cole wrote:
On 3/13/2012 11:19 PM, James wrote:
On 14/03/12 14:09, Peter Cole wrote:
On 3/13/2012 5:00 PM, James wrote:
On 14/03/12 03:25, Peter Cole wrote:
On 3/12/2012 11:42 PM, Ralph Barone wrote:
Peter wrote:

No, it's typically a switching regulator, which modulates duty
cycle,
AKA PWM.

The use of a switching regulator does not necessarily result in the
LED
being switched ON and OFF at a high rate.

I think it does, by definition.


I haven't analyzed any, so I
can't comment on how many bike light current regulators PWM the LED,
versus
more sophisticated control methods.

As an EE, I can't think of any more "sophisticated" method, unless
you're modulating it to send data or something. FWIW, I've designed a
few PWM circuits for lamp (arc) control, a few switching power supply
regulators and a motor controller or 2.


Then consider a constant current source implemented as a buck converter
where the inductor current doesn't fall to zero.

The average current is kept constant by PWM, and the current is never
zero. It's operating in continuous conduction mode.


I'm not sure what point you're attempting to make.

It appears that in the quoted conversation above, you believe that "by
definition" the use of a switching regulator results in the LED being
switched ON and OFF at a high rate.

If that is what you meant, you are incorrect.


You do like to split hairs. You are rather arbitrarily deciding that
"switching an LED on and off" means zero current.

What on earth else can it mean?

rant snipped

Peter, I gave you plenty of wriggle room to amend your statement, but
instead you've gone off on a rant that I don't care to respond to.

--
JS.

On 14/03/12 15:53, Phil W Lee wrote:
considered Wed, 14 Mar 2012 08:40:48
+1100 the perfect time to write:

On 14/03/12 05:23, Phil W Lee wrote:
considered Tue, 13 Mar 2012 12:29:21
+1100 the perfect time to write:

On 13/03/12 11:12, Phil W Lee wrote:

Then if they are a German resident they may choose to fit two lights,
and only use the flashing one outside Germany (with the primary light
being StVZO approved).
Or if they are resident outside Germany, they can fit a dual mode
light that is approved in their own country, and exercise the visitor
privilege to use that light (but in non-flashing mode) when in
Germany.

So you've answered the question very nicely. Other manufacturers offer
a Germany only model without flash mode. Why shouldn't the German
manufacturers supply a rest of the world model that includes flash mode?

Why would they?

To increase market share out side of Germany. Some folks want longer
battery life and believe (rightly or wrongly) that a flashing light is
more prominent. But we've been over this before.

Seems that anything much more than the 20 hours I can get from my
StVZO light is only obtainable by reducing the visibility.
Of course, it may be that you don't want to charge batteries so often,
but then why not fit a generator?

I hate charging batteries, and yes I use a dynamo.

They seem to be able to sell their lights all over the world without
modifying them.
I would also suggest that it's much easier to disable an optional mode
than it is to add one that the electronics in the light are not
originally designed to provide.

As, IIRC, Mr. Liebermann noted recently, once there are electronics in
there (and there will be for current regulation and high/low beam
modes), adding a flash mode will not change the bottom line by more than
a few cents, if that.

Only true on lights that do use PWM.
If output is varied by using different values of resistor, you'd have
to add the PWM, and redesign the light.

To dim an LED with resistors would be very wasteful of energy.

--
JS.

On 3/14/2012 4:39 PM, SMS wrote:
On 3/14/2012 10:39 AM, Duane wrote:

The one I probably use the most is the yellow pages locator to find the
closest ice cream.

But that doesn't tell you the best ice cream, only the closest. I can
get my 14 yo son to come on a ride by promising a stop at Rick's
Rather Rich http://www.yelp.com/biz/ricks-ice-cream-palo-alto.


Some time being the closest is better than being the best. But if you
want to know about the best, you probably want to talk to Peter. A
choice between Steve's and Ben & Jerries is sometime hard to make. We
have decent ice cream in Montreal but if I'm riding 80k north of here,
the choices are more limited.

On 3/14/2012 4:49 PM, James wrote:
On 14/03/12 15:43, Peter Cole wrote:
On 3/13/2012 11:19 PM, James wrote:
On 14/03/12 14:09, Peter Cole wrote:
On 3/13/2012 5:00 PM, James wrote:
On 14/03/12 03:25, Peter Cole wrote:
On 3/12/2012 11:42 PM, Ralph Barone wrote:
Peter wrote:

No, it's typically a switching regulator, which modulates duty
cycle,
AKA PWM.

The use of a switching regulator does not necessarily result in the
LED
being switched ON and OFF at a high rate.

I think it does, by definition.


I haven't analyzed any, so I
can't comment on how many bike light current regulators PWM the LED,
versus
more sophisticated control methods.

As an EE, I can't think of any more "sophisticated" method, unless
you're modulating it to send data or something. FWIW, I've designed a
few PWM circuits for lamp (arc) control, a few switching power supply
regulators and a motor controller or 2.


Then consider a constant current source implemented as a buck
converter
where the inductor current doesn't fall to zero.

The average current is kept constant by PWM, and the current is never
zero. It's operating in continuous conduction mode.


I'm not sure what point you're attempting to make.

It appears that in the quoted conversation above, you believe that "by
definition" the use of a switching regulator results in the LED being
switched ON and OFF at a high rate.

If that is what you meant, you are incorrect.


You do like to split hairs. You are rather arbitrarily deciding that
"switching an LED on and off" means zero current.

What on earth else can it mean?

rant snipped

Peter, I gave you plenty of wriggle room to amend your statement, but
instead you've gone off on a rant that I don't care to respond to.


Well thanks for wasting my time then.

On Wed, 14 Mar 2012 13:39:50 -0400, Duane
wrote:

On 03/14/2012 01:25 PM, Peter Cole wrote:
On 3/14/2012 10:17 AM, Duane wrote:
On 03/14/2012 09:36 AM, sms88 wrote:
On 3/14/2012 4:05 AM, Duane Hebert wrote:

LOL. Last one for me was when I asked my son why his touch screen was
shattered again.
"Took a puck, dad." Why you need a cell phone in your pocket when
you're
playing hockey is sort of beyond me.
But then again, I'm "so twentieth century."

I'm thinking of getting my kids a second phone, a cheap flip phone, to
take to school or on trips. $30/year on Pageplus (Verizon MVNO), and
there's really no reason they need a smart phone at school. At least
they don't have iPhones which are often stolen, only $100 gently used
HTC Incredibles on Pageplus. I used to think there was no reason to have
a phone at school at all, until two recent code-red incidents at their
school. It was good to be able to send and receive texts with news of
what was happening because the students were scared and knew nothing of
what was happening.


He has a cheap phone now and an iPod Touch for his music and WIFI. The
iPod is on its 3rd screen. He also has blue tooth head phones because
the plugs keep getting screwed up.

My daughter (college frosh) has the same setup. She uses an ancient flip
phone for calls & text and an iTouch for surf & music on school or home
WiFi. She's too frugal for a data plan (me so proud). When I got her the
touch, I put it in a semi-case, having heard so many cracked screen
stories, so far so good. My son, on the other hand, was an early smart
phone adapter, he's on his fourth or fifth, I've lost count, I think his
carrier will own him well into middle age, but it's his money (mostly).

I considered getting an iTouch for myself, after seeing my friends
iPhone in action last year. The idea of a nice GPS unit combined with
Google maps seemed like a cyclist's dream come true. Instead, I got a
Kindle Fire because the format seemed so much more useful for the kind
of stuff I do most of the time. It does have WiFi location, which I
guess works OK in an urban environment. I sideloaded Google maps, and it
appears they cache for when you're out of hotspot range, but I haven't
yet taken it out for a ride. Boston isn't a very large city, but this
season I hope to find some new routes through some dense and unfamiliar
neighborhoods, I hope it will help.


I have a couple of apps on my iPhone to track rides. I use them to map
a ride and share it with some friends. The club also posts the maps in
garmin format that I can import into one of the apps on my phone. I
generally don't need this when riding with the group as there are enough
guys with garmin cycle computers to find our way around.

The one I probably use the most is the yellow pages locator to find the
closest ice cream.

Out of curiosity, how long will your phone battery last when tracking
with the GPS? I've tried it with two different phones and neither
would last until I got back from my Sunday ride.
I tried with straight GPS and assisted GPS and in either case the
battery was dead when I got home.


--
Cheers,

John B.

Peter Cole wrote:
On 3/13/2012 11:19 PM, James wrote:
On 14/03/12 14:09, Peter Cole wrote:
On 3/13/2012 5:00 PM, James wrote:
snip

I'm not sure what point you're attempting to make.

It appears that in the quoted conversation above, you believe that "by
definition" the use of a switching regulator results in the LED being
switched ON and OFF at a high rate.

If that is what you meant, you are incorrect.


You do like to split hairs. You are rather arbitrarily deciding that
"switching an LED on and off" means zero current.

What is your definition of "OFF"? Where I come from OFF = 0.

Peter Cole wrote:
On 3/12/2012 11:42 PM, Ralph Barone wrote:
Peter wrote:
On 3/12/2012 5:50 AM, Phil W Lee wrote:
Jeff considered Sun, 11 Mar 2012
16:09:07 -0700 the perfect time to write:

On Sun, 11 Mar 2012 15:26:01 -0700,
wrote:

On 3/11/2012 3:16 PM, Jeff Liebermann wrote:

Trivia: All high power (0.5w) LED lights use PWM (pulse width
modulation) for dimming, to control heating, and to improve
efficiency. Even in the full brightness mode, they flash. You can
see the PWM with a photo diode and oscilloscope, or just shine the
light on a rotating colored disk to see the strobe effect. I wonder
if Germany considers this as a flashing bicycle light.

I would view the Wikipedia article on bicycle lighting with a lot of
grains of salt. It's been hijacked by several individuals with a
specific agenda. A huge number of obvious errors and if you try to
correct them, someone undoes the correction.

I don't see any evidence of hijacking or an agenda in the history
since 2005:
http://en.wikipedia.org/w/index.php?title=Bicycle_lighting&offset=&limit=500 &action=history
Looks like mostly additions, spelling corrections, juggling
references, and discussions (talk). Which individuals are allegedly
responsible?

If you're referring to my mention of PWM in bicycle lighting, that was
verified by me with several LED flashlights and one Bike Planet
bicycle headlight. At such power levels, one would need to be a
masochist to use a linear regulator (except in retrofit flashlight
bulbs). Would you like me to post an oscilloscope photo?

So based on your analysis of ONE bicycle light, you assert that all
use PWM?
Why on earth would they?
All you need is a current limiting device, which is typically a
resistor,

No, it's typically a switching regulator, which modulates duty cycle, AKA PWM.

The use of a switching regulator does not necessarily result in the LED
being switched ON and OFF at a high rate.

I think it does, by definition.

I beg to disagree. Your PC power supply contains a switching regulator, yet
it produces constant DC voltages. A buck converter for LED lighting use
could be designed to produce any desired amount of "flicker", right down to
essentially zero if desired.

I haven't analyzed any, so I
can't comment on how many bike light current regulators PWM the LED, versus
more sophisticated control methods.

As an EE, I can't think of any more "sophisticated" method, unless you're
modulating it to send data or something. FWIW, I've designed a few PWM
circuits for lamp (arc) control, a few switching power supply regulators
and a motor controller or 2.

OK, unclear language on my part. What I meant to say was that I didn't know
how many lights did a raw PWM on the LED (and relied on the inherent
current limiting of the battery ESR to avoid frying the LED) and how many
employed actual switching current regulators, which may have some residual
ripple, but effectively provide a constant DC current to the LED.

PS: Would you consider hysteretic PWM to be a different beast from regular
(compare desired waveform to triangle reference, switch transistors
accordingly) PWM?

On 3/14/2012 9:50 PM, John B. wrote:
On Wed, 14 Mar 2012 13:39:50 -0400,
wrote:

On 03/14/2012 01:25 PM, Peter Cole wrote:
On 3/14/2012 10:17 AM, Duane wrote:
On 03/14/2012 09:36 AM, sms88 wrote:
On 3/14/2012 4:05 AM, Duane Hebert wrote:

LOL. Last one for me was when I asked my son why his touch screen was
shattered again.
"Took a puck, dad." Why you need a cell phone in your pocket when
you're
playing hockey is sort of beyond me.
But then again, I'm "so twentieth century."
I'm thinking of getting my kids a second phone, a cheap flip phone, to
take to school or on trips. $30/year on Pageplus (Verizon MVNO), and
there's really no reason they need a smart phone at school. At least
they don't have iPhones which are often stolen, only $100 gently used
HTC Incredibles on Pageplus. I used to think there was no reason to have
a phone at school at all, until two recent code-red incidents at their
school. It was good to be able to send and receive texts with news of
what was happening because the students were scared and knew nothing of
what was happening.

He has a cheap phone now and an iPod Touch for his music and WIFI. The
iPod is on its 3rd screen. He also has blue tooth head phones because
the plugs keep getting screwed up.
My daughter (college frosh) has the same setup. She uses an ancient flip
phone for calls& text and an iTouch for surf& music on school or home
WiFi. She's too frugal for a data plan (me so proud). When I got her the
touch, I put it in a semi-case, having heard so many cracked screen
stories, so far so good. My son, on the other hand, was an early smart
phone adapter, he's on his fourth or fifth, I've lost count, I think his
carrier will own him well into middle age, but it's his money (mostly).

I considered getting an iTouch for myself, after seeing my friends
iPhone in action last year. The idea of a nice GPS unit combined with
Google maps seemed like a cyclist's dream come true. Instead, I got a
Kindle Fire because the format seemed so much more useful for the kind
of stuff I do most of the time. It does have WiFi location, which I
guess works OK in an urban environment. I sideloaded Google maps, and it
appears they cache for when you're out of hotspot range, but I haven't
yet taken it out for a ride. Boston isn't a very large city, but this
season I hope to find some new routes through some dense and unfamiliar
neighborhoods, I hope it will help.

I have a couple of apps on my iPhone to track rides. I use them to map
a ride and share it with some friends. The club also posts the maps in
garmin format that I can import into one of the apps on my phone. I
generally don't need this when riding with the group as there are enough
guys with garmin cycle computers to find our way around.

The one I probably use the most is the yellow pages locator to find the
closest ice cream.
Out of curiosity, how long will your phone battery last when tracking
with the GPS? I've tried it with two different phones and neither
would last until I got back from my Sunday ride.
I tried with straight GPS and assisted GPS and in either case the
battery was dead when I got home.


I have an iPhone 4 and running either MapMyRide, AllSport LE or Strava,
with each set to ignore stops I have been able to record a 5 hour ride.
But this is with the screen off. If I keep the screen on, it lasts only
a couple of hours.

On 3/14/2012 6:50 PM, John B. wrote:

Out of curiosity, how long will your phone battery last when tracking
with the GPS? I've tried it with two different phones and neither
would last until I got back from my Sunday ride.
I tried with straight GPS and assisted GPS and in either case the
battery was dead when I got home.

On my Android phone the GPS drains the battery in about an hour. A GPS
uses a lot of power. You could get a battery sleeve for the iPhone to
increase the run time.

On 3/15/2012 11:03 AM, SMS wrote:
On 3/14/2012 6:50 PM, John B. wrote:

Out of curiosity, how long will your phone battery last when tracking
with the GPS? I've tried it with two different phones and neither
would last until I got back from my Sunday ride.
I tried with straight GPS and assisted GPS and in either case the
battery was dead when I got home.

On my Android phone the GPS drains the battery in about an hour. A GPS
uses a lot of power. You could get a battery sleeve for the iPhone to
increase the run time.


An hour? Even with the screen closed? I guess I'll find out as a
friend soaked his iPhone sailing and switched to Android.