Guest
Hello,
I have hacked a clockradio and i need to supply it with power from a
12v battery. How do i invert DC to AC?
I have hacked a clockradio and i need to supply it with power from a
12v battery. How do i invert DC to AC?
J
John Fields
Guest
On Thu, 16 Oct 2008 10:13:25 -0700 (PDT), stiganielsen@gmail.com wrote:
When you say "the radio had a transformer..." does that mean you removed
it?
JF
---
When you say "the radio had a transformer..." does that mean you removed
it?
JF
M
Michael Black
Guest
On Thu, 16 Oct 2008, stiganielsen@gmail.com wrote:
You run it off batteries, and then build up a crystal oscillator
and divider chain to send pulses to the actual clock that it will count
and use to keep time.
You don't need AC to run the clock, after all the existing power supply
is there to convert AC to the DC that the clock needs. You do need
a source of 60Hz pulses so the clock has something to count, the AC
line usually being used for that purpose.
So you look at the clock IC, the large one, and try to find a datasheet
or at least pinout for the IC. Then from there, you can figure out
where the DC goes to power the IC, and where it gets a sample of the
AC line to "clock" the clock. That point will need to be connected
to a source of pulses at the line frequency (which I guess may
be 50Hz if you are talking about 240v AC line.
This sort of thing was common decades ago, when digital clock building
was a big wave. Now, clocks have become so cheap nobody really does
it.
You need to rethink your problem, or at least restate your problem.
There has to be a reason for you wanting to run this off a battery,
explain that and a solution is easier to derive. I'm assuming you
want it for the clock, and not the radio, but that's an assumption.
Some clock radios have a 9v battery to keep it going when the
power goes off, though I've never had one to know if they actually
keep the clock ticking away, or just supply power so the current
time isn't lost in a temporary power loss. If they keep ticking,
then that's likely a better choice for your project, since you
no longer need to supply the pulses for the clock IC. Then it
would just be a matter of applying DC voltage from the battery
to where the rectifier from the AC transformer hits the filter
capacitor.
But, if it's the clock you need, then maybe find an alternative.
I bought an LCD clock a decade ago for about five dollars, and when
the button battery died, I wired in an AA battery, and it just
runs forever. No alarm feature though. But more expensive
LCD clocks do have an alarm feature, and with some work one
could use that to turn something else on, if that's the point
of this project.
I bought an "atomic clock" at a garage sale this spring for all
of 2.00, so one has to have a good reason for modifying a clock
radio for battery operation in order to make it worth doing
the work.
Michael
You run it off batteries, and then build up a crystal oscillator
and divider chain to send pulses to the actual clock that it will count
and use to keep time.
You don't need AC to run the clock, after all the existing power supply
is there to convert AC to the DC that the clock needs. You do need
a source of 60Hz pulses so the clock has something to count, the AC
line usually being used for that purpose.
So you look at the clock IC, the large one, and try to find a datasheet
or at least pinout for the IC. Then from there, you can figure out
where the DC goes to power the IC, and where it gets a sample of the
AC line to "clock" the clock. That point will need to be connected
to a source of pulses at the line frequency (which I guess may
be 50Hz if you are talking about 240v AC line.
This sort of thing was common decades ago, when digital clock building
was a big wave. Now, clocks have become so cheap nobody really does
it.
You need to rethink your problem, or at least restate your problem.
There has to be a reason for you wanting to run this off a battery,
explain that and a solution is easier to derive. I'm assuming you
want it for the clock, and not the radio, but that's an assumption.
Some clock radios have a 9v battery to keep it going when the
power goes off, though I've never had one to know if they actually
keep the clock ticking away, or just supply power so the current
time isn't lost in a temporary power loss. If they keep ticking,
then that's likely a better choice for your project, since you
no longer need to supply the pulses for the clock IC. Then it
would just be a matter of applying DC voltage from the battery
to where the rectifier from the AC transformer hits the filter
capacitor.
But, if it's the clock you need, then maybe find an alternative.
I bought an LCD clock a decade ago for about five dollars, and when
the button battery died, I wired in an AA battery, and it just
runs forever. No alarm feature though. But more expensive
LCD clocks do have an alarm feature, and with some work one
could use that to turn something else on, if that's the point
of this project.
I bought an "atomic clock" at a garage sale this spring for all
of 2.00, so one has to have a good reason for modifying a clock
radio for battery operation in order to make it worth doing
the work.
Michael
Guest
On Oct 16, 6:56 pm, stiganiel...@gmail.com wrote:
found at:http://www.paulanders.com/G5-LED/ver1/datablad.pdf
I would really appreciate any good suggestions on where to find a
schematic for this circuit
Btw. the radio had a transformer 220v AC > 7v AC the datasheet can be
found at:http://www.paulanders.com/G5-LED/ver1/datablad.pdf
I would really appreciate any good suggestions on where to find a
schematic for this circuit
Guest
On Oct 16, 9:56 am, stiganiel...@gmail.com wrote:
Hacked as in you don't mind it not working anymore if you continue?
What's the AC for?
Why not just put +12V on pin 20, and ground on pin 15?
Just my $0.02. Which ain't worth much... finance.yahoo.com
Michael
Hacked as in you don't mind it not working anymore if you continue?
What's the AC for?
Why not just put +12V on pin 20, and ground on pin 15?
Just my $0.02. Which ain't worth much... finance.yahoo.com
Michael
J
Jasen Betts
Guest
On 2008-10-16, stiganielsen@gmail.com <stiganielsen@gmail.com> wrote:
two-phase precise-frequency AC to drive the display and timer ?
As I understand it those chips don't actually need the negative part
of the AC (which makes your life easier) but they do need the
frequency to be right (or they keep time very poorly)
MM5369 is a chip that can make the right frequency for you then you
just need to feed the output to some transistors to provide an
inverted signal and boost the current so it can drive your display
Bye.
Jasen
you have an LM8560 (or similar) based digital alarm clock and need a
two-phase precise-frequency AC to drive the display and timer ?
As I understand it those chips don't actually need the negative part
of the AC (which makes your life easier) but they do need the
frequency to be right (or they keep time very poorly)
MM5369 is a chip that can make the right frequency for you then you
just need to feed the output to some transistors to provide an
inverted signal and boost the current so it can drive your display
Bye.
Jasen
M
Michael A. Terrell
Guest
Jasen Betts wrote:
The MM5369 has been obsolete for so long (20 years?) that National
Semiconductor doesn't even list it as obsolete. Also, there were
special versions like 100 Hz so if you find old stock, or surplus it may
not be 60 Hz. Even companies like Jameco don't list the MM5369 any
more.
A better choice would be a crystal & divider chain, but keep in mind
that some clock chips wand a 50% duty cucle at 60 Hz. Digikey has a lot
of suitable crystals. Fo instance, they have 60 kHz crystals starting
at 72 cebts. Divide by 1000 and yo have 60 Hz.
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There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
The MM5369 has been obsolete for so long (20 years?) that National
Semiconductor doesn't even list it as obsolete. Also, there were
special versions like 100 Hz so if you find old stock, or surplus it may
not be 60 Hz. Even companies like Jameco don't list the MM5369 any
more.
A better choice would be a crystal & divider chain, but keep in mind
that some clock chips wand a 50% duty cucle at 60 Hz. Digikey has a lot
of suitable crystals. Fo instance, they have 60 kHz crystals starting
at 72 cebts. Divide by 1000 and yo have 60 Hz.
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The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
Guest
On Oct 16, 8:26 pm, Michael Black <et...@ncf.ca> wrote:
Thanks for all the great info!
Achually my plan is as follows: Use the display of the clockradio for
my arduino, showing values. The advantage is that the clockradio only
will take up 3 digital pins to show values .xx:xx (hours and minutes)
The plan was to make the display light up and setting the alarm to the
value i need to show (through a loop counting up to the value on hours
and a reset and a loop)
This means i don't need the timing functions of the chip. Neither do i
need the alarm or radio features..(I achually already snapped those
parts off the print)
Thanks in advance.
Stig
Thanks for all the great info!
Achually my plan is as follows: Use the display of the clockradio for
my arduino, showing values. The advantage is that the clockradio only
will take up 3 digital pins to show values .xx:xx (hours and minutes)
The plan was to make the display light up and setting the alarm to the
value i need to show (through a loop counting up to the value on hours
and a reset and a loop)
This means i don't need the timing functions of the chip. Neither do i
need the alarm or radio features..(I achually already snapped those
parts off the print)
Thanks in advance.
Stig
J
Jasen Betts
Guest
On 2008-10-17, Michael A. Terrell <mike.terrell@earthlink.net> wrote:
the other half
I was thinking 2.457600 Mhz / 40960 using a CD4040 to drive the
crystal and divide by 4096 and a CD4018 to divide by 10 more and
provide a 50% duty cycle.
Bye.
Jasen
I just cheked the local electronics shop and they listed 1 in stock.
yeah, if you don't give them that half the display will be brighter than
the other half
what's a good way to divide a crystal by 1000 with a 12-15V supply?
I was thinking 2.457600 Mhz / 40960 using a CD4040 to drive the
crystal and divide by 4096 and a CD4018 to divide by 10 more and
provide a 50% duty cycle.
Bye.
Jasen
M
Michael A. Terrell
Guest
Jasen Betts wrote:
I wouldn't touch that on a bet. I never buy singles of obsolete
parts.
You don't really understand the design, do you? Some of the dividers
need a 50% duty cycle, or they don't work, at all.
Sigh. Use a 78L05 voltage regulator to power the oscilator & divider,
and a single transistor amp for level conversion.
You do realize that the higher the crystal frequency, the more power
the divider circuit uses, don't you?
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There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
I wouldn't touch that on a bet. I never buy singles of obsolete
parts.
You don't really understand the design, do you? Some of the dividers
need a 50% duty cycle, or they don't work, at all.
Sigh. Use a 78L05 voltage regulator to power the oscilator & divider,
and a single transistor amp for level conversion.
You do realize that the higher the crystal frequency, the more power
the divider circuit uses, don't you?
--
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listed, or I will not see your messages.
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your account: http://www.usenettools.net/ISP.htm
There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
J
Jasen Betts
Guest
On 2008-10-18, Michael A. Terrell <mike.terrell@earthlink.net> wrote:
inadiquate. (by 'just' I meant 'merely')
low frequency,
cycle?
512:488 might be close enough and you can get that using a CD4040 (or
similar TTL ripple counter chip) and and an 8-input and gate,
else if you need 50:50 you'll need a flip-flop too.
you're asking for a fair collection of parts...
anyway the original poster only needs a simple RC oscillator driving a
couple high-side transistor switches, as he's apparently not using the
timebase.
Bye.
Jasen
Fair enough, by saying that I meant that my availability test was
inadiquate. (by 'just' I meant 'merely')
that's a surprise! I'd not expect timing to be that critical at such a
low frequency,
so what's a good way to divide a crystal by 1000. giving a 50% duty
cycle?
512:488 might be close enough and you can get that using a CD4040 (or
similar TTL ripple counter chip) and and an 8-input and gate,
else if you need 50:50 you'll need a flip-flop too.
you're asking for a fair collection of parts...
yeah, but the LED display would use much more anyway
anyway the original poster only needs a simple RC oscillator driving a
couple high-side transistor switches, as he's apparently not using the
timebase.
Bye.
Jasen
M
Michael A. Terrell
Guest
Jasen Betts wrote:
Not really. Maybe $2 worth of CMOS, a crystal a couple caps a 2 cent
transistor and some nickle resistors. There are dual BCD counter ICs
like the mc14518 will give a clean divide by 100 followed by a divide by
five, and a divide by two, or use mc14040 and configure it to count to
500, then use a flip flop o divide by two.
I have seen oscilator modules that put out 60 Hz. Commodore used one
in their SX-64 computer, and I have seen them in some old battery backed
clocks.
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your account: http://www.usenettools.net/ISP.htm
There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
Divide by 500, followed by a divide by wo.
Not really. Maybe $2 worth of CMOS, a crystal a couple caps a 2 cent
transistor and some nickle resistors. There are dual BCD counter ICs
like the mc14518 will give a clean divide by 100 followed by a divide by
five, and a divide by two, or use mc14040 and configure it to count to
500, then use a flip flop o divide by two.
I have seen oscilator modules that put out 60 Hz. Commodore used one
in their SX-64 computer, and I have seen them in some old battery backed
clocks.
--
http://improve-usenet.org/index.html
aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.
If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm
There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
J
Jasen Betts
Guest
On 2008-10-19, Michael A. Terrell <mike.terrell@earthlink.net> wrote:
4018 can do the final
divide by 10 and give a 50% duty cycle (saving the flip flop)
so you can drive the crystal from a transistor? I've not seen that
done before.
harder to get or my clocks were crap.
Bye.
Jasen
resistors cost more than caps?
hmm, that 4518 looks like a CMOS part number
4018 can do the final divide by 10 and give a 50% duty cycle (saving the flip flop)
so you can drive the crystal from a transistor? I've not seen that
done before.
The clocks I've seen just used R-C oscilators, maybe 50Hz modules were
harder to get or my clocks were crap.
Bye.
Jasen
Guest
On 20 Okt., 12:05, Jasen Betts <ja...@xnet.co.nz> wrote:
How should i connect power to the ic of the clockradio if i just want
the display to work, being able to set the hours and minutes. (using
it to display other values i need to read out from my robotic devices)
As earlier described i need to power it from a dc supply.
Hope you can give me some advice on this issue, thanks
Stig
On 2008-10-19, Michael A. Terrell <mike.terr...@earthlink.net> wrote:
so what's a good way to divide a crystal by 1000. giving a 50% duty
cycle?
Divide by 500, followed by a divide by wo.
512:488 might be close enough and you can get that using a CD4040 (or
similar TTL ripple counter chip) and and an 8-input and gate,
else if you need 50:50 you'll need a flip-flop too.
you're asking for a fair collection of parts...
Not really. Maybe $2 worth of CMOS, a crystal a couple caps a 2 cent
transistor and some nickle resistors. There are dual BCD counter ICs
like the mc14518 will give a clean divide by 100 followed by a divide by
resistors cost more than caps?
five, and a divide by two, or use mc14040 and configure it to count to
500, then use a flip flop o divide by two.
hmm, that 4518 looks like a CMOS part number
How should i connect power to the ic of the clockradio if i just want
the display to work, being able to set the hours and minutes. (using
it to display other values i need to read out from my robotic devices)
As earlier described i need to power it from a dc supply.
Hope you can give me some advice on this issue, thanks
Stig
J
Jasen Betts
Guest
On 2008-10-20, stiganielsen@gmail.com <stiganielsen@gmail.com> wrote:
because that seems to be the most popular one
build this: (view in courier font)
7V ----+------
|
+-[18K]-------|--------+
| | |
| +--------+ |
| | | |
| | . . . .|. . . . | +-[10K]---> Freq
| | . VCC(8) . | |
| | . . | |
| +--RES(4) OUT(3)--+-----+-----+-----------> D1
| . LM555 . |
+-------TH(6) DIS(7)--- | .---> D2
| . . | |/
+-------TR(2) CV(5)-- +--[560R]---| PN2222
100nF | . . |\| or BC337
===== . GND(1) . ~\
| . . . .|. . . . |
| | |
+-------------+-----------------------------+--
|
|
---+-- gnd
That should hit the ball park of 60Hz give approximately equal time
on each output and accept sufficient current to drive your LED display
Freq goes to pin 25 and D1 and D2 connect to the display.
if the display is too bright you may need to add some voltage drop by
putting (for example) 3 or 4 1N4001 diodes in series on D1 and D2.
(too bright will wear it out quiickly)
Bye.
Jasen
you still haven't said what chip it uses, I'll assume "8560"
because that seems to be the most popular one
build this: (view in courier font)
7V ----+------
|
+-[18K]-------|--------+
| | |
| +--------+ |
| | | |
| | . . . .|. . . . | +-[10K]---> Freq
| | . VCC(8) . | |
| | . . | |
| +--RES(4) OUT(3)--+-----+-----+-----------> D1
| . LM555 . |
+-------TH(6) DIS(7)--- | .---> D2
| . . | |/
+-------TR(2) CV(5)-- +--[560R]---| PN2222
100nF | . . |\| or BC337
===== . GND(1) . ~\
| . . . .|. . . . |
| | |
+-------------+-----------------------------+--
|
|
---+-- gnd
That should hit the ball park of 60Hz give approximately equal time
on each output and accept sufficient current to drive your LED display
Freq goes to pin 25 and D1 and D2 connect to the display.
if the display is too bright you may need to add some voltage drop by
putting (for example) 3 or 4 1N4001 diodes in series on D1 and D2.
(too bright will wear it out quiickly)
Bye.
Jasen