battery powered?

J

James Varga

Guest
Okay - I've got a simple project going on here and being a bit of a noob I
need some help ;)

I've got three x 3mm blue LED's hanging off a QT110 (touch sensitive IC)

The QT110 consumes 20uA

Each LED consumes (i think) about 20mA.

I only have 5mm height to put this in so I'm stuck with a button cell
battery.

The only other thing there is is a 10uF cap.

So help me out - how long would a battery of say 620mA last under constant
use?

The other thing I would think of asking is that is there an easy
way/schematic for charging a battery like this?
 
Theres your problem! Try ultra low current LEDs, ie either low current
ones @2mA or else ultrabrights run at even lower. Also try flashing
them, or using LCD if possible instead.
Click to expand...
Okay - I had a look around and couldn't find any 2mA LED's - only the
typical 20mA and 30mA - any suggestions?
 
On Thu, 7 Oct 2004 23:42:34 +0100, the renowned "James Varga"
<james@jamesvarga.com> wrote:

Theres your problem! Try ultra low current LEDs, ie either low current
ones @2mA or else ultrabrights run at even lower. Also try flashing
them, or using LCD if possible instead.

Okay - I had a look around and couldn't find any 2mA LED's - only the
typical 20mA and 30mA - any suggestions?
Click to expand...
Just use an LED that is very bright at 20mA, and it will be quite
acceptable at one or two mA.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
Okay - I had a look around and couldn't find any 2mA LED's - only the
typical 20mA and 30mA - any suggestions?

---
HLMP4700. About 35 cents at Digi-Key
Click to expand...
Thanks John but all I see there are red, yell, and green ones - I need a
blue one - or do they exist?
 
On Fri, 8 Oct 2004 01:17:13 +0100, "James Varga"
<james@jamesvarga.com> wrote:

Okay - I had a look around and couldn't find any 2mA LED's - only the
typical 20mA and 30mA - any suggestions?

---
HLMP4700. About 35 cents at Digi-Key

Thanks John but all I see there are red, yell, and green ones - I need a
blue one - or do they exist?
Click to expand...
---
Dunno...

You might want to Google around for "high efficiency blue LED" without
the quotes, or take Spehro's advice and get a superbright 20mA one and
run it at 2mA.

--
John Fields
 
On Fri, 08 Oct 2004 17:14:25 GMT, the renowned "Clarence" <no@No.com>
wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:e5cdm0hutbeo0i7lfbmbndalnvn419c4qn@4ax.com...
On Fri, 8 Oct 2004 01:17:13 +0100, "James Varga"
james@jamesvarga.com> wrote:

Okay - I had a look around and couldn't find any 2mA LED's - only the
typical 20mA and 30mA - any suggestions?

---
HLMP4700. About 35 cents at Digi-Key

Thanks John but all I see there are red, yell, and green ones - I need a
blue one - or do they exist?

---
Dunno...

You might want to Google around for "high efficiency blue LED" without
the quotes, or take Spehro's advice and get a superbright 20mA one and
run it at 2mA.
--
John Fields


http://www.mpja.com/productview.asp?product=12568+OP

$1.25 Each. 3900mcp, 4 volts, 20ma, 5mm dia.
Click to expand...
Or these are cheaper @ 0.45/each for 20/BIN:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3845006474

I am ONLY a customer not a representative of this site.
Click to expand...
I'm not.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message
news:9uldm0d0htj0ksr1900mjole6fsjk7r4m7@4ax.com...
On Fri, 08 Oct 2004 17:14:25 GMT, the renowned "Clarence" <no@No.com
wrote:
snip

http://www.mpja.com/productview.asp?product=12568+OP

$1.25 Each. 3900mcp, 4 volts, 20ma, 5mm dia.

snip

I am ONLY a customer not a representative of this site.

I'm not.
Click to expand...
Not what?

"Not - "not a representative " OR???
 
"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message
news:3qmdm0do557loc69oapiogn0tlqq1oi9v9@4ax.com...
On Fri, 08 Oct 2004 18:09:08 GMT, the renowned "Clarence" <no@No.com
wrote:


"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message
news:9uldm0d0htj0ksr1900mjole6fsjk7r4m7@4ax.com...
On Fri, 08 Oct 2004 17:14:25 GMT, the renowned "Clarence" <no@No.com
wrote:
snip

http://www.mpja.com/productview.asp?product=12568+OP

$1.25 Each. 3900mcp, 4 volts, 20ma, 5mm dia.

snip

I am ONLY a customer not a representative of this site.

I'm not.

Not what?

"Not - "not a representative " OR???

Not not. ;-)

Spelling error! That is "Nut - nut." ;-)
Click to expand...
 
On Fri, 08 Oct 2004 18:09:08 GMT, the renowned "Clarence" <no@No.com>
wrote:

"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message
news:9uldm0d0htj0ksr1900mjole6fsjk7r4m7@4ax.com...
On Fri, 08 Oct 2004 17:14:25 GMT, the renowned "Clarence" <no@No.com
wrote:
snip

http://www.mpja.com/productview.asp?product=12568+OP

$1.25 Each. 3900mcp, 4 volts, 20ma, 5mm dia.

snip

I am ONLY a customer not a representative of this site.

I'm not.

Not what?

"Not - "not a representative " OR???
Click to expand...
Not not. ;-)



Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
"Clarence" <no@No.com> wrote in message
news:RVz9d.8519$nj.1609@newssvr13.news.prodigy.com...
"John Fields" <jfields@austininstruments.com> wrote in message
news:e5cdm0hutbeo0i7lfbmbndalnvn419c4qn@4ax.com...
On Fri, 8 Oct 2004 01:17:13 +0100, "James Varga"
james@jamesvarga.com> wrote:

Okay - I had a look around and couldn't find any 2mA LED's -
only the
typical 20mA and 30mA - any suggestions?

---
HLMP4700. About 35 cents at Digi-Key

Thanks John but all I see there are red, yell, and green ones - I
need a
blue one - or do they exist?

---
Dunno...

You might want to Google around for "high efficiency blue LED"
without
the quotes, or take Spehro's advice and get a superbright 20mA one
and
run it at 2mA.
--
John Fields


http://www.mpja.com/productview.asp?product=12568+OP

$1.25 Each. 3900mcp, 4 volts, 20ma, 5mm dia.

I am ONLY a customer not a representative of this site.
Click to expand...
I'm also a satisfied customer of MPJA. However, one needs to remember
the following:

MPJA sells surplus, so unless they say that the part is new, one should
assume that the part could be surplus or used.

LEDs in general, and even more so with blue and white, are recent and
advancing technology, so what you may save on less expenaive LEDs may be
eaten up by disappointing performance. Or worse, as I found when I
bought a few LEDs: the blue ones became intermittent after a few tens of
minutes of operation.

I've since purchased blue LEDs directly from Nichia, and found them to
be very reliable and of excellent quality. Just a satisfied customer.
;-)
 
On Thu, 7 Oct 2004 23:42:34 +0100, "James Varga"
<james@jamesvarga.com> wrote:

Theres your problem! Try ultra low current LEDs, ie either low current
ones @2mA or else ultrabrights run at even lower. Also try flashing
them, or using LCD if possible instead.

Okay - I had a look around and couldn't find any 2mA LED's - only the
typical 20mA and 30mA - any suggestions?
Click to expand...
---
HLMP4700. About 35 cents at Digi-Key

--
John Fields
 
James Varga wrote:
Okay - I've got a simple project going on here and being a bit of a
noob I need some help ;)

I've got three x 3mm blue LED's hanging off a QT110 (touch sensitive
IC)

The QT110 consumes 20uA

Each LED consumes (i think) about 20mA.

I only have 5mm height to put this in so I'm stuck with a button cell
battery.

The only other thing there is is a 10uF cap.

So help me out - how long would a battery of say 620mA last under
constant use?

The other thing I would think of asking is that is there an easy
way/schematic for charging a battery like this?
Click to expand...
I've been reading this thread and I decided to Google for QT110.
It came up with this:

http://www.qprox.com/products/qtouch.php

from which it appears, on cursory examination, that the capacitor
is a 10 nF ceramic. The data there comments that:"Most QT110
family devices are designed for human touch; some, like the QT110
and QT118H even include piezo beeper drive logic"

I haven't found a spec for the /OUT pin but the chip is spec'ed for
+3 to +5vdc supply.

The blue LED I have here will light quite nicely as an indicator
when drawing 0.5mAmps. But whether the /OUT pin can drive
three of them I don't know.

The OP should be aware that LEDs are not like filament bulbs
and that their operating current is part of the design of the
application.

HTH
--
Graham W http://www.gcw.org.uk/ PGM-FI page updated, Graphics Tutorial
WIMBORNE http://www.wessex-astro-society.freeserve.co.uk/ Wessex
Dorset UK Astro Society's Web pages, Info, Meeting Dates, Sites & Maps
Change 'news' to 'sewn' in my Reply address to avoid my spam filter.
 
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