# 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

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What I am attempting is to take 7 specific voltages, and display
certain numbers for these specific voltages on an alpha-numeric
display.

What I currently have is a resistor ladder that breaks up the voltage.
The resistors form a ladder that breaks up the 5v from a voltage
regulator into reference signals to determine at what voltages an
LM339N will use to ground each corresponding LED. It use 1% resistors
to make sure I get exact reference voltages because in the higher gears
the signal is very close and there is not much gap between voltages.
The output voltages from the sensor are as follows
1st gear = 1.782v
2nd gear = 2.242v
3rd gear = 2.960v
4th gear = 3.630v
5th gear = 4.310v
6th gear = 4.660v
Neutral = 5.000v
The comparators in this circuit will turn on each LED as follows:
1st LED = Anything over 1.022v
2nd LED = Anything over 2.043v
3rd LED = Anything over 2.660v
4th LED = Anything over 3.356v
5th LED = Anything over 4.052v
6th LED = Anything over 4.526v

I now want to take thes voltages and convert them to show the proper
gear on an alpha-numeric display.

How can I turn what I have working in to alpha numeric?

Or, Do I have to start a whole new circuit.  Something that takes the
voltage and turns it into a digital signal and then sends to an A/N LED
display.

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

On 5 Feb 2006 10:39:30 -0800, snipped-for-privacy@persona.ca put finger to
keyboard and composed:

Use the comparator outputs to drive a 74LS148 8-line-to-3-line
priority encoder (or something similar), and then follow this with a
BCD-to-7 segment decoder/driver. I'd use an additional comparator to
detect neutral, and then apply this signal to the enable input of the
74148 so that the display is blanked.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

How about using a LM3914 in dot mode with each output driving the required
pins of the LED display via diodes?

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

Anyone with a good idea feel free to post schematic, as it will help me
make sense of all this.

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

On 5 Feb 2006 15:23:44 -0800, snipped-for-privacy@persona.ca put finger to
keyboard and composed:

You could probably do everything with a single PICAXE-18X chip:
http://www.rev-ed.co.uk/docs/axe001_xparts.pdf

The PICAXE has a built-in ADC and an on-chip BASIC interpreter. No
comparators would be needed, only the LED digit, and driver
transistors for each segment. The chip can be programmed via a PC
serial port.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

you'd need an extra level of buffering. AIUI the 3914 has current-limited
outputs which would make the "6" dimmer than the "1"

--

Bye.
Jasen

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

True.

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

I'd consider using different resistors to get a more even spread.

run that output into a priority encoder chip and then the output from that
into a BCD to 7-segment chip.
neutral will need to be a special case.done with a bunch of gates...

It's that or use a microcontroller, it depends on how much space you have
and wether you prefer to program with a soldering iron or a keyboard.
a microcontroller with a DAC in it would obsolete your lm339 comparators...

Is this is for a motorbike?

A/N = alphanumeric?  is 7-segment enough?
_  _       _
|  _| _| |_| |_   _
| |_  _|   |  _| | |

(view with a fixed pitch font like courier)

Bye.
Jasen

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

yes it is for a motorbike, GSXR actually.

Love that line about the program with soldering iron.  I have no fear
in programming with a computer, I actually do this for a
living(computers) but not electronics.

I just need to know what chips to use for my soldering iron Basc
language.
And seven segment is enough as an "n" can be made.

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

< snipped-for-privacy@persona.ca

**  LED displays are rendered in invisible in average daylight.

.......  Phil

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

On Mon, 6 Feb 2006 12:25:50 +1100, "Phil Allison"

LOL, yeah, tell that to the traffic light designers and message board
manufacturers. I suppose the auto manufacturers are wrong too, as are
the manufacturers of truck indicator and stop lights.

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

"The Real Andy"

=  Andrew Pearson:

Andy is a despicable, chronic alcoholic, anencephalic,  autistic moron from
Brisbane.

Then there are his bad points.

BTW

Anyone can try a typical 7 segment LED display in bright daylight and see
the outcome.

........  Phil

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

On Mon, 6 Feb 2006 21:33:39 +1100, "Phil Allison"

YAWN....

Quote from Phil
"**  LED displays are rendered in invisible in average
daylight."

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

Since you have digital outputs from your comparators, if you don't want to
send them to a PIC and do some code-crunching, send these to an EPROM as the
address lines and use the outputs to drive the seven-segment display.
Program the EPROM to suit.

Cheers.

Ken

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

The line's not mine unforunately I encountered it in one of the
*.electronics* newsgroups last week.

ISTR someone has already offered a list including part numbers.
I don't see the priority encoder chip in the Jaycar catalogue (paper)
but someone offered a part number and I expect they can nominate a source
for the part too.

getting the 'n' will probably need to be done separately from the rest of the

for the 'n' three small diodes (1N914),a 1k resistor and a cheap transistor
should be sufficient, (in addition to your existing setup , the 7-seg
display and its resistors)

If you want to go the microcontroller route this is an ideal first project
(no interrupts, just a simple loop reading the dac and comparing the input
with a list of numbers, looking up another list of bit-patterns and sending
out the output)

being an Atmel user myself I'd say use a ATtiny26 microcontroller (\$8nz)
(Jaycar doesn't list that part, but an industrial place near me has it
http://www.sicom.co.nz ) 7 resistors (to limit the LED current) and a
common anode 7 segment display, a resonator to clock it, and a pin header
for the programer, power supply, connectors for your other harware etc...

The chip will run off 2.7-6V so your exisiting 5V would work.

for a programmer the silicon chip kit looks good, but there are cheaper
parallel port progrmmers that work well too,

This looks like the official atmel in-circuit programmer circuit,
which I have used, and had no problems with: 1 74HC244 chip (mine
has the markings sanded off) and 3 passives
<
http://www.lancos.com/e2p/avrisp-stk200.gif) and theres
plenty of free software out there.

The chip has an internal clock that could be used instead of the resonator
but it takes a more complex programmer to activate the clock.

The chip has flash memory for the program so your \$8 gets you potentially
1000 tries to get your software right.

There's free C and Asssmber tools. there'a a BASIC too, dunno if it's free
(it's for windows which I dislike, and I prefer C to BASIC anyway), but it
seems to pop up on P2P searches....

If you decide to use a PIC instead I'd reccomend you get or build a decent
programmer those serial-port powered ones are kind of flaky, but the ones
that are powered externally work well.

Bye.
Jasen

Re: 7 specific volatges to to 1,n,2,3,4,5,6 numbers in Alpha-numeric Display

snipped-for-privacy@persona.ca wrote:

Here is something that might set you going in the right direction if
you decide to use a pic.
http://homepages.kcbbs.gen.nz/moby/atod.asm
this particular widget is a flying spot VU meter using 12 LEDs across 4
port pins of
an 8 pin pic and the onboard a to d converter, but by rejigging the
breakpoints to your voltages (V/5*256) and using different bit patterns
on 7 output lines of a 14 pin pic the job would be done. Oh yes you can
get plenty bright enough 7 seg displays to be daylight readable...or
you could go retro and use a numitron (but you would need something
like a ULN2003 as the little pic doesn't have enough output grunt).
M