Digital voltmeter - amp hour meter
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Posts: 46,084
Hi Angus,
If you use the LM3914, you only get 10 steps for the whole range. All
you need is connect each LM3914 output to the stamp. And you have 6
pins left for the LCD. But this is not a very precise solution.
In this case, I would go for a Maxim A/D converter instead of the
Stamp, depending on the display you want to use (MAX 136 or MAX
7129).
On the other hand, if you want to make another measurement (like amp
hour), with the same Stamp and the same alphanumeric 16-character
LCD,
then I would use a Stamp and a 2-chanel A/D converter (MAX 110 or MAX
111).
Now to measure amp hour, you need a clock, yes ? Then have a look at
Dallas Semiconductors DS 1302 (on Maxim's site). It's a great
real-time clock with a battery or supercap backup system.
Those 2 circuits (MAX 110 and DS 1302) saves Stamp pins (4 and 3-wire
communication). You need some more Stamp I/Os for the LCD...
This is only an idea on how I would begin.
Have a look at www.maxim-ic.com, you'll find the complete datasheets.
Hope this helps...
Phil.
|
|
Original Message
| From: "kirtkirt1265" <kirtkirt1265@y...>
| To: <derennep@s...>
| Sent: Tuesday, October 22, 2002 1:09 AM
| Subject: scratch that last message...
|
|
| | phil-
| | What we actually want to do is to do what you describe below. We
| | would be greatful if you could provide us with instructions on how
| to
| | do this. our goal is to build a digital voltmeter and a amp hour
| | counter. We would appreciate your reply asap.
| | cheers,
| | Angus
| | >Another solution, if you want to use a Stamp, is to connect the
| | >outputs of the LM3914 to the Stamp, and program it to drive an
| | >alphanumeric LCD display... but this is more complex and require
| | >programming.
| |
| |
|
If you use the LM3914, you only get 10 steps for the whole range. All
you need is connect each LM3914 output to the stamp. And you have 6
pins left for the LCD. But this is not a very precise solution.
In this case, I would go for a Maxim A/D converter instead of the
Stamp, depending on the display you want to use (MAX 136 or MAX
7129).
On the other hand, if you want to make another measurement (like amp
hour), with the same Stamp and the same alphanumeric 16-character
LCD,
then I would use a Stamp and a 2-chanel A/D converter (MAX 110 or MAX
111).
Now to measure amp hour, you need a clock, yes ? Then have a look at
Dallas Semiconductors DS 1302 (on Maxim's site). It's a great
real-time clock with a battery or supercap backup system.
Those 2 circuits (MAX 110 and DS 1302) saves Stamp pins (4 and 3-wire
communication). You need some more Stamp I/Os for the LCD...
This is only an idea on how I would begin.
Have a look at www.maxim-ic.com, you'll find the complete datasheets.
Hope this helps...
Phil.
|
|
Original Message
| From: "kirtkirt1265" <kirtkirt1265@y...>
| To: <derennep@s...>
| Sent: Tuesday, October 22, 2002 1:09 AM
| Subject: scratch that last message...
|
|
| | phil-
| | What we actually want to do is to do what you describe below. We
| | would be greatful if you could provide us with instructions on how
| to
| | do this. our goal is to build a digital voltmeter and a amp hour
| | counter. We would appreciate your reply asap.
| | cheers,
| | Angus
| | >Another solution, if you want to use a Stamp, is to connect the
| | >outputs of the LM3914 to the Stamp, and program it to drive an
| | >alphanumeric LCD display... but this is more complex and require
| | >programming.
| |
| |
|
Comments
> Those 2 circuits (MAX 110 and DS 1302) saves Stamp pins (4 and 3-
wire
> communication). You need some more Stamp I/Os for the LCD...
Add a 74HC595 shift register and you can run the LCD with only one
extra pin. Share the clock and data with the other SPI chips and
only add a CS line for the shift register. There's even an example
somewhere using the 1302, 74hc595 and an LCD. Of course, now I can't
find the link :P