Digest Number 38

Archiver

>
> thanks, but I must confess that I don't follow/comprehend the majority
> of your statement.
>
> Words I don't grok include "source current", PNP, base resistors
> ,...<G>
Source means to supply the current from the positive of the power
supply to the device connected to ground(as your schematic
shows your relays). The most common type of driver is a NPN
circuit which connects a load(that is hooked to the positive supply)
to ground.
> It appears to me that I have it the NTE2014(ULN 2003) working as I
> need it to although I'm still waiting for UPS to deliver a basic stamp
> II to me so that I can do a final assembly and test....also, I thought
> the ULN WAS a darlington. Is a "PNP" darlington different from
> the NTE 2014 that I have?
>
The ULN is a NPN darlington driver circuit. Its sounds like in your
test you are just touching the postive supply of to the relay wires
and activating them(bypassing the ULN).

Archiver

Mike, thanks for taking the time to respond.

grasshopper gains more enlightenment!

I assembled it all tonite and darn if it doesn't work! [noparse]:)[/noparse]

The keys to my dilemma was (seems to me) that
1) I was putting the common wire on pin 9 instead of pin 8, and it was the
opposite polarity for what the schematic originally had (my fault)
2) I had blown the original ULN2003, probably because it was (according to
the electrical clerk at Tinkertronics) for 5 volts and I sent 15 volts
through it. (kinda my fault<G>)
3) I had not put a zener diode(or equivalent) across pins 8 and 9 of the
NTE2014 (ULN2003 15 volt version). (my fault)

It works flawlessly as I've coded it so far. This is so dang cool I cain't
hardly stand it!

Turn it on, the red light/led comes on and 3 beeps sound. You push the
button labelled "short", two beeps sound, and the LCD displays a 20 second
countdown as archers walk to the line. One beep sounds, the red goes out,
and green light/led comes on telling the archers to shoot. After 90
seconds (which the LCD has counted down) the green goes out and the yellow
led/light comes on (no beeps - don't want to disturb the archers). LCD
displays "YELLOW ZONE" and counts down the last 30 seconds of shooting, and
then red light replaces yellow, 3 beeps sound to stop shooting.
I have a "long" button that is exactly the same but green goes for 210
seconds instead of 90 seconds and LCD messages reflect that the period is
longer.

Sounds pretty simple, now, huh<G>?

I have ordered the 1-watt audio amplifier to try to make the speaker (or
another noisemaker like a piezo) audible from 50 meters away, and I need to
add a switch to the stamp so that I can control the value of a variable in
the code loop.
(there are times when the green and yellow needs to run twice)

I received tonite a new carrier board, and as soon as I can get an info
sheet on it from Parallax I'll make all the circuitry on it as well - when I
got the first carrier board I didn't realize that it wouldn't take a
wallwart power supply, and the super board does.

I'm also editing the original schematic to reflect all changes and trying to
make up a parts list of all the components.

I'll post it ALL on the net and send a listing to the LOSA and to this group
when all is said and done, in the hopes that others may find it of use as a
starting point upon which to improve.

hmmm. If I put a slide switch onto a pin of the stamp, along with a 10K
resistor(since that's the strength resistor used on a button switch), I'll
be able to measure whether it is "on" or not. Will that cause excessive
drain on the battery though? I've looked through the manual but couldn't
find any example of using a slide switch that stays on or off. Does this
set off alarm bells with anyone? [noparse]:)[/noparse]


Mike DeMetz wrote:

> The ULN is a NPN darlington driver circuit. Its sounds like in your
> test you are just touching the postive supply of to the relay wires
> and activating them(bypassing the ULN).

--
ARC in Lago Vista, TX

"Jazz is not dead, it just smells funny." - Frank Zappa