 |
Search Sci.Electronics.Basics |
|
|
|
|
|
|
 |
|
|
Sci.Electronics.Basics -> "Simple" hour/minute binary clock?
There are 31 messages in this thread.
You are currently looking at messages 20 to 31.
|
Author: Jeff FindleyDate: 08:43 20-10-06
|
|
<owner@chickenfriedsteak.us> wrote in message
news:1161346654.772369.59030@m7g2000cwm.googlegroups.com...
>
> Battery voltage doesn't matter, whatever will drive the circuit. I'd
> prefer to not use one of the huge 12v flashlight batteries though,
> since I wanted to hook a few batts up in parallel and mount clips to
> the circuitboard so the whole thing can be hung on a wall. 9v maybe?
> The chips will need a 5v I assume (everything I've been working with so
> far does). To drive those, I've cheated and used 5v power adaptors
> from Radioshack, but like I said I wanted this to be a self-contained
> thing.
If your chips want to run at 5V, why not use four NiMH batteries in series
to get 5.8V? The AA NiMH cells I have say they're 1.2 volts. I've seen
cheap ones on sale at Micro Center for $4 for a pack of 4. I've also picked
up, admittedly cheaply designed, chargers for these for about $10. I'd bet
even Big Lots has some of these. It would seem these would simplify the
circuit design and save you money in the long run since you won't have to
keep buying batteries for the thing.
Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)
|
|
|
|
|
|
Jeff Findley wrote:
> If your chips want to run at 5V, why not use four NiMH batteries in series
> to get 5.8V? The AA NiMH cells I have say they're 1.2 volts. I've seen
> cheap ones on sale at Micro Center for $4 for a pack of 4. I've also picked
> up, admittedly cheaply designed, chargers for these for about $10. I'd bet
> even Big Lots has some of these. It would seem these would simplify the
> circuit design and save you money in the long run since you won't have to
> keep buying batteries for the thing.
>
> Jeff
> --
> "They that can give up essential liberty to obtain a
> little temporary safety deserve neither liberty nor
> safety"
> - B. Franklin, Bartlett's Familiar Quotations (1919)
Yes, that would work better. I don't know what the chips needed to run
this are rated at (I'm waiting to see the schematic from John so I know
what parts I need to get at Radioshack - we've only got one in my area
that stills ICs and not just cell phones, and it's a long drive so I
only want to make one trip). Once I know what I need to pick up I
guess I'll have to figure out what they run at. Like I said, my
knowledge of circuits, etc. is limited to following schematic diagrams
I find online, but in my experience, everything I've used has run on
either a +5v or a +12v. In the past I've had to get creative with
batteries, hooking a few of a certain type in parallel and then hooking
the parallel "bunches" in series to get near the right voltage - very
inefficient and costly, but it worked and the batteries lasted a fairly
decent length of time. My other option, which I don't want to do here,
is stripping the ends of a cheap A/C adaptor.
I picked up a few books the other day on beginner projects in
electronics, hoping to find something in them like what I've requested
here, but no such luck. They've taught me a lot, though, and I'm
already thinking of ways to adapt John's circuit to drive something
other than LEDs (but I'm going to tackle getting this to work, first).
Thanks again for all your help and once I have schematics and a
finished product, I'll be sure to post a link to a picture.
|
|
|
|
Author: Homer J SimpsonDate: 13:40 20-10-06
|
|
<owner@chickenfriedsteak.us> wrote in message
news:1161364629.357111.4080@b28g2000cwb.googlegroups.com...
> Like I said, my
> knowledge of circuits, etc. is limited to following schematic diagrams
> I find online, but in my experience, everything I've used has run on
> either a +5v or a +12v. In the past I've had to get creative with
> batteries, hooking a few of a certain type in parallel and then hooking
> the parallel "bunches" in series to get near the right voltage - very
> inefficient and costly, but it worked and the batteries lasted a fairly
> decent length of time. My other option, which I don't want to do here,
> is stripping the ends of a cheap A/C adaptor.
Buy a set of clip leads and you can connect to the adaptor. Rat Shack should
have these.
http://www.allelectronics.com/ is a place to shop if you can make up an
order. Check out their kits also.
|
|
|
|
Author: Rich GriseDate: 13:42 20-10-06
|
|
On Fri, 20 Oct 2006 05:17:34 -0700, owner wrote:
> John Fields wrote:
>> On 18 Oct 2006 05:07:05 -0700, owner@chickenfriedsteak.us wrote:
> (snip)
>> ---
>> OK. I'll post a schematic to alt.binaries.schematics.electronic
>> tomorrow, but since Google won't let you access binaries through Google
>> Groups I'll email it to you as well.
>>
>> BTW, what battery voltage do you want to use?
>
> I really appreciate all your help on this! A big part of this project and
> a few other small ones I'm working on is to take my ability to read
> schematics and build something from them and actually learn what some of
> these components/circuits do so I can be a little more flexible and
> creative on some larger things I want to build down the road.
>
> Battery voltage doesn't matter, whatever will drive the circuit. I'd
> prefer to not use one of the huge 12v flashlight batteries though, since I
> wanted to hook a few batts up in parallel and mount clips to the
> circuitboard so the whole thing can be hung on a wall. 9v maybe? The
> chips will need a 5v I assume (everything I've been working with so far
> does). To drive those, I've cheated and used 5v power adaptors from
> Radioshack, but like I said I wanted this to be a self-contained thing.
>
A wall wart is perfectly acceptable, and will get you your +5 without
you having to design a power supply.
I've seen switching wall warts smaller than a pack of cigarettes, with
5 to 10 watts out - you could hide one of those inside your enclosure.
Good Luck!
Rich
|
|
|
|
Author: Rich GriseDate: 13:45 20-10-06
|
|
On Fri, 20 Oct 2006 08:43:07 -0400, Jeff Findley wrote:
>
> <owner@chickenfriedsteak.us> wrote in message
> news:1161346654.772369.59030@m7g2000cwm.googlegroups.com...
>>
>> Battery voltage doesn't matter, whatever will drive the circuit. I'd
>> prefer to not use one of the huge 12v flashlight batteries though, since
>> I wanted to hook a few batts up in parallel and mount clips to the
>> circuitboard so the whole thing can be hung on a wall. 9v maybe? The
>> chips will need a 5v I assume (everything I've been working with so far
>> does). To drive those, I've cheated and used 5v power adaptors from
>> Radioshack, but like I said I wanted this to be a self-contained thing.
>
> If your chips want to run at 5V, why not use four NiMH batteries in series
> to get 5.8V? The AA NiMH cells I have say they're 1.2 volts. I've seen
> cheap ones on sale at Micro Center for $4 for a pack of 4. I've also
> picked up, admittedly cheaply designed, chargers for these for about $10.
> I'd bet even Big Lots has some of these. It would seem these would
> simplify the circuit design and save you money in the long run since you
> won't have to keep buying batteries for the thing.
>
> Jeff
I wouldn't use NiMH's for anything. I've had a very bad experience with
a couple of batches of NiMH's that after about a year's time, wouldn't
even hold a charge.
If you can get low enough current with LED's, I'd suggest 3 or 4 C or
D alkalines, and use CMOS, which has a wide supply range.
But, like I said a couple of posts ago, a wall wart should be perfectly
acceptable.
Good Luck!
Rich
|
|
|
|
Author: Jeff FindleyDate: 14:42 20-10-06
|
|
"Rich Grise" <rich@example.net> wrote in message
news:pan.2006.10.20.10.46.04.540761@example.net...
> I wouldn't use NiMH's for anything. I've had a very bad experience with
> a couple of batches of NiMH's that after about a year's time, wouldn't
> even hold a charge.
I'll admit that some of the really cheap ones I've gotten aren't all that
great, so usually they end up in the kids toys. ;-) For "good" NiMH
batteries, I've usually paid around $10 for four (Energizer, Panasonic,
Rayovac, etc). I've not had any of these go bad yet.
Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)
|
|
|
|
Author: LostgallifreyanDate: 20:50 20-10-06
|
|
Rich Grise <rich@example.net> wrote in
news:pan.2006.10.20.10.46.04.540761@example.net:
> I wouldn't use NiMH's for anything. I've had a very bad experience with
> a couple of batches of NiMH's that after about a year's time, wouldn't
> even hold a charge.
>
> If you can get low enough current with LED's, I'd suggest 3 or 4 C or
> D alkalines, and use CMOS, which has a wide supply range.
>
A lot of NiMH troubles can be traced to microthicknesses of grime or
nonconductive salts on the terminals. I had some that looked like they were
decaying at different rates in charge retention, and I decided to try a bit
of brasso on their terminals and give them another go, and they behaved
equally again, camera use went from around an hour to around four hours.
That's a big recovery considering there didn't appear to be a problem with
terminals before cleaning. It doesn't take a lot for the charger to fail to
push enough current, it can drop well before the little LED's make the
failure obvious.
Re alkalines, are any of them rechargeable? That's not a facetious
question, if there are any, I want some.
|
|
|
|
Author: Dave PlattDate: 00:25 21-10-06
|
|
In article <Xns986312B03C75zoodlewurdle@140.99.99.130>,
Lostgallifreyan <no-one@nowhere.net> wrote:
>A lot of NiMH troubles can be traced to microthicknesses of grime or
>nonconductive salts on the terminals. I had some that looked like they were
>decaying at different rates in charge retention, and I decided to try a bit
>of brasso on their terminals and give them another go, and they behaved
>equally again, camera use went from around an hour to around four hours.
>That's a big recovery considering there didn't appear to be a problem with
>terminals before cleaning. It doesn't take a lot for the charger to fail to
>push enough current, it can drop well before the little LED's make the
>failure obvious.
Fascinating - thanks for the report.
Some Caig Labs DeOxIt might be equally effective at getting off the
grime and restoring the contact quality.
>Re alkalines, are any of them rechargeable? That's not a facetious
>question, if there are any, I want some.
Rayovac used to make specialized rechargeable alkaline batteries. I
gather that these are discontinued (they never really caught on) but
that Pure Energy in Canada is making equivalents.
They do work, I understand, but aren't an ideal solution. They
apparently start out with a charge capacity similar to a standard
alkaline, but their capacity drops off somewhat each time they're
discharged and recharged. There seems to be an inverse relationship
between lifetime (in number of cycles) and depth of discharge - deep
discharge reduces the number of total cycles you can get before the
battery is degraded to the point where it's no longer useful. Also,
a specialized charger is required - a standard NiCd or NiMH charger
cannot be used.
Although Pure Energy states that their battery can be recharged up to
500 times, another report I've read suggests that 50 cycles at
half-discharge and 10 cycles at deep discharge can be expected, and
that a complete discharge can leave the cell in a non-rechargeable
state and thus kill it completely. Possibly the technology has
improved since the latter report was written in 2002, or possibly the
500-cycle number assumes a very shallow discharge.
Rechargeable alkalines also seem to have a relatively high internal
resistance, which limits their ability to deliver high amounts of
current (400 mA max for an AA cell is suggested by one writeup).
For most rechargeable applications, NiMH seems the best solution for
devices that you can keep "topped up" on a charger frequently, while
the older NiCd types may still be best for applications where you need
to charge the device and then stick it in a box and not think about it
for several months and then expect it to work reliably.
--
Dave Platt <dplatt@radagast.org> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!
|
|
|
|
Author: John FieldsDate: 15:56 21-10-06
|
|
On 20 Oct 2006 10:17:09 -0700, owner@chickenfriedsteak.us wrote:
>
>Jeff Findley wrote:
>
>> If your chips want to run at 5V, why not use four NiMH batteries in series
>> to get 5.8V? The AA NiMH cells I have say they're 1.2 volts. I've seen
>> cheap ones on sale at Micro Center for $4 for a pack of 4. I've also picked
>> up, admittedly cheaply designed, chargers for these for about $10. I'd bet
>> even Big Lots has some of these. It would seem these would simplify the
>> circuit design and save you money in the long run since you won't have to
>> keep buying batteries for the thing.
>>
>> Jeff
>> --
>> "They that can give up essential liberty to obtain a
>> little temporary safety deserve neither liberty nor
>> safety"
>> - B. Franklin, Bartlett's Familiar Quotations (1919)
>
>Yes, that would work better. I don't know what the chips needed to run
>this are rated at (I'm waiting to see the schematic from John so I know
>what parts I need to get at Radioshack - we've only got one in my area
>that stills ICs and not just cell phones, and it's a long drive so I
>only want to make one trip). Once I know what I need to pick up I
>guess I'll have to figure out what they run at. Like I said, my
>knowledge of circuits, etc. is limited to following schematic diagrams
>I find online, but in my experience, everything I've used has run on
>either a +5v or a +12v. In the past I've had to get creative with
>batteries, hooking a few of a certain type in parallel and then hooking
>the parallel "bunches" in series to get near the right voltage - very
>inefficient and costly, but it worked and the batteries lasted a fairly
>decent length of time. My other option, which I don't want to do here,
>is stripping the ends of a cheap A/C adaptor.
>
>I picked up a few books the other day on beginner projects in
>electronics, hoping to find something in them like what I've requested
>here, but no such luck. They've taught me a lot, though, and I'm
>already thinking of ways to adapt John's circuit to drive something
>other than LEDs (but I'm going to tackle getting this to work, first).
>Thanks again for all your help and once I have schematics and a
>finished product, I'll be sure to post a link to a picture.
---
I just posted the schematic and some supplementary material to abse
and also emailed it to you since you can't access abse through
Google groups.
--
John Fields
Professional Circuit Designer
|
|
|
|
Author: LionelDate: 00:59 23-10-06
|
|
On 16 Oct 2006 19:32:54 -0700, owner@chickenfriedsteak.us opined:
>I've been all up and down Google for a couple hours now trying to find
>project instructions for a binary clock that displays just the simple
>hours/minutes but can't find it. All the projects I'm finding are BCD
>displays only, or display the time in a combination of four or five
>rows (including seconds). I was really looking to build one like a
>watch I saw, displaying hours on top and minutes below in two rows of
>LEDs:
>
> 8 4 2 1 (h)
>32 16 8 4 2 1 (m)
>
>Can anyone point me in the direction of a project like this?
A project? A CD4040 binary counter chip, some sort of clock oscillator
(a 555 would do for testing purposes) & a bunch of LEDs would do the
trick nicely.
--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
|
|
|
|
Author: John FieldsDate: 06:07 23-10-06
|
|
On Mon, 23 Oct 2006 14:59:52 +1000, Lionel <usenet@imagenoir.com>
wrote:
>On 16 Oct 2006 19:32:54 -0700, owner@chickenfriedsteak.us opined:
>
>>I've been all up and down Google for a couple hours now trying to find
>>project instructions for a binary clock that displays just the simple
>>hours/minutes but can't find it. All the projects I'm finding are BCD
>>displays only, or display the time in a combination of four or five
>>rows (including seconds). I was really looking to build one like a
>>watch I saw, displaying hours on top and minutes below in two rows of
>>LEDs:
>>
>> 8 4 2 1 (h)
>>32 16 8 4 2 1 (m)
>>
>>Can anyone point me in the direction of a project like this?
>
>A project? A CD4040 binary counter chip, some sort of clock oscillator
>(a 555 would do for testing purposes) & a bunch of LEDs would do the
>trick nicely.
---
Nope.
--
John Fields
Professional Circuit Designer
|
|
|
|
|
|
|
|
|
Contact | Electronic Portal
|
|
|
