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help with project with map & LED's

R

Ronald

Jan 1, 1970
0
WAUW, I cannot believe my own eyes!!!

Sorry, this is the most horrible piece of calculation I have ever produced.
I blame it on the mice on the attick who kept me up most of the night!! It
wasn't before 3.30 AM before I finally slept, or at least, that was the last
time I consciously saw on the clock.

Forget about it, yes, the 4 A SCR would suffice...

Ronald


(Sorry mice, but now the traps are out of the closet and armed with fresh,
smelly cheese!)



Ronald said:
I see, I see, clever. Simple but clever

But are you sure if I hook up 200 LED's (in case of feldspar which has
been mined in almost all of the mines) to one SCR it will hold? The C106D
is rated for 4A, whereas 200 x 0,10 mA =20A. Shouldn't I use one with much
higher amperage?

The idea is worth trying, a test wouldn't cost me much, apart from the
SCR's I would have to buy, don't have so many in stock.

Let me know if I am wrong about the capacity of the SCR!

Thanks!

Ronald


ehsjr said:
Ronald said:
Sounds like a possibility. I know not much about digital electronics,
but some of the basic concepts I know. (Never got beyound the
SN74-series in jy time, and then decided that there were other interests
to persue...)

Thanks for the idea.

Ronald




On Tue, 10 Oct 2006 21:23:37 +0200, Ronald wrote:


Hi,

I hope someone can help me into the right direction with the following
project:

-I want to make an overview map (1x2 m) for a certain area in Norway
with
a large number of mines where different minerals were taken out.

-every mine is represented by one LED

-there are 8 push-buttons, each representing a specific mineral
(quartz,
feldspar, mica, beryll, REE-minerals, uranium, scandium and gemstones)

-a push on one of the buttons will light the respective LED's were that
mineral has been taken out, and will reset all other previous states

-a second push at the same button will have no effect

-there are up to 200-300 mines in this area


I suppose it will be pretty basic, each push-button connected to a
flip-flop, which in it's turn connects to the respective LED's, I
suppose
connected through buffers.

If someone can help me with the flip-flop part and the resets, I guess
I
will manage the rest.

Many thanks in advance.

You can do this with SCR's - one for each mineral:


+12 -----+------------------+---------+---{{{-----+
| | | |
| [LED] [LED] [LED]
| | | |
| [1K] [1K] [1K]
| | | |
| Pb1 [SCR1 [SCR2] [SCR8]
| ___ /| /| /|
+---o o---[330]--+ +---------+---{{{-----+---+
| | | | |
| +--->|---------+ | | |
| D1 | | | |
| Pb2 | | | |
| ___ | | | |
+---o o---[330]------------+ | |
| | | | |
| +--->|---------+ | |
| D2 | | |
{{{ {{{ {{{ {{{
| | | |
| Pb8 | | |
| ___ | | |
+---o o---[330]------------------------+ o
| | + |
+--->|---------+---[C1]----+----+ .->| N/C
D8 | | | |
+---[3.3K]--+ [RY1] o
| |
Gnd -------------------------------------------+---+

How it works: pressing any pusbutton biases the respective
SCR gate to turn on, and energizes the relay briefly through
C1, a 100 uF capacitor, as C1 charges. This opens the ground
path to all the SCR's (via the normally closed contact of the
relay), turning off any previously on SCR. The 3.3K resistor
discharges C1 between button presses.

As soon as the relay drops, the SCR corresponding to the
button being pressed turns on. The diodes prevent any other
SCR from turning on. The LEDs connected to the SCR turn on and
stay on until the next time a button is pressed. Each LED
you connect to the SCR needs its own current limiting resistor.
If you use red LEDs, 1K will limit the current to ~10 mA - for
brighter you could use a 470 ohm resistor instead of the 1K.
The C106D SCR works nicely. It is capable of 4 amps, so it
can light a LOT of LEDS. You may need to experiment with
the value of C1, depending on what relay you use. It affects
the timing of how long you need to press a button to turn the
SCR on.

If some mines contain more than 1 mineral, they can be
wired to multiple SCRs through diodes. Small signal diodes
like 1N4148s will be fine for that purpose. 1N4001's should
be used for the diodes connected to the pushbuttons.

Ed
 
B

Ban

Jan 1, 1970
0
Ronald said:
WAUW, I cannot believe my own eyes!!!

Sorry, this is the most horrible piece of calculation I have ever
produced. I blame it on the mice on the attick who kept me up most of
the night!! It wasn't before 3.30 AM before I finally slept, or at
least, that was the last time I consciously saw on the clock.

Forget about it, yes, the 4 A SCR would suffice...

Ronald


(Sorry mice, but now the traps are out of the closet and armed with
fresh, smelly cheese!)

Don't worry lately I was off by 2x10^3 due to wrong conversion of Quads and
BTUs, cazzo!
 
E

ehsjr

Jan 1, 1970
0
Ronald said:
I see, I see, clever. Simple but clever

But are you sure if I hook up 200 LED's (in case of feldspar which has been
mined in almost all of the mines) to one SCR it will hold? The C106D is
rated for 4A, whereas 200 x 0,10 mA =20A. Shouldn't I use one with much
higher amperage?

The idea is worth trying, a test wouldn't cost me much, apart from the SCR's
I would have to buy, don't have so many in stock.

Let me know if I am wrong about the capacity of the SCR!

Thanks!

Ronald

The SCRs will handle the current with 1K resistors as
the limiters. With 2A current a possibility, you want
to mount the SCRs on heat sinks. Also, make sure your
relay contacts can handle at least 2 amps.

Ed
 
P

Peter Heitzer

Jan 1, 1970
0
Ronald said:
I hope someone can help me into the right direction with the following
project:
-I want to make an overview map (1x2 m) for a certain area in Norway with a
large number of mines where different minerals were taken out.
-every mine is represented by one LED
-there are 8 push-buttons, each representing a specific mineral (quartz,
feldspar, mica, beryll, REE-minerals, uranium, scandium and gemstones)
-a push on one of the buttons will light the respective LED's were that
mineral has been taken out, and will reset all other previous states
-a second push at the same button will have no effect
-there are up to 200-300 mines in this area
The simplest solution is to use an array of 8 radio buttons or a tap changer.
If you want an electronic solution I'd propose using an 8 input priority
encoder like 74hc148, a 4bit latch and a 3 to 8 decoder like 74hc138.
The 74hc148 has an output that changes if any of the inputs is active.
This output latches the 3 bit address of the highest active input.
These 3bit are decoded by the 74hc138.
Of course you will need buffers to driver the leds.

I suppose it will be pretty basic, each push-button connected to a
flip-flop, which in it's turn connects to the respective LED's, I suppose
connected through buffers.
 
R

Rich Grise

Jan 1, 1970
0
I see, I see, clever. Simple but clever

But are you sure if I hook up 200 LED's (in case of feldspar which has
been mined in almost all of the mines) to one SCR it will hold? The C106D
is rated for 4A, whereas 200 x 0,10 mA =20A. Shouldn't I use one with much
higher amperage?

You should probably run them in series strings. You'd need more volts, but
that shouldn't be a problem, since you very probably are using the mains
supply anyway. If you use series strings of, say, 10 LEDs, that'd be a Vf
of 12 volts or so (depending on the VF of the leds, of course), at only
20 ma, for a total of 4 A, if my arithmetic is correct. Or, you could use
even longer strings, depending on how many mines you have per set.

Good Luck!
Rich
 
R

Rich Grise

Jan 1, 1970
0
(Sorry mice, but now the traps are out of the closet and armed with fresh,
smelly cheese!)


Use peanut butter. Mice don't really like cheese, they just eat it because
they're starving, which makes the bait pretty ineffective if there's other
mouse food around.

Or capture them live and take them to the pet shop to be sold for snake
food. ;-)

Peanut butter is also good bait for a live trap. :)

Good Luck!
Rich
 
R

Rich Grise

Jan 1, 1970
0
Why not just use push buttons which switch off when you lift your finger?
That way you can look at more than one mineral at once. Push the buttons
in pairs and you might just be surprised at the mineral associations which
come to light.

Or, better yet, push-on, push-off buttons. ;-)

Cheers!
Rich
 
J

jasen

Jan 1, 1970
0
Ronald wrote:


+12 -----+------------------+---------+---{{{-----+
| | | |
| [LED] [LED] [LED]
| | | |
| [1K] [1K] [1K]
| | | |
| Pb1 [SCR1 [SCR2] [SCR8]
| ___ /| /| /|
+---o o---[330]--+ +---------+---{{{-----+---+
| | | | |
| +--->|---------+ | | |
| D1 | | | |
| Pb2 | | | |
| ___ | | | |
+---o o---[330]------------+ | |
| | | | |
| +--->|---------+ | |
| D2 | | |
{{{ {{{ {{{ {{{
| | | |
| Pb8 | | |
| ___ | | |
+---o o---[330]------------------------+ o
| | + |
+--->|---------+---[C1]----+----+ .->| N/C
D8 | | | |
+---[3.3K]--+ [RY1] o
| |
Gnd -------------------------------------------+---+

hey that's neat!


have you considered this.


+12 -+--. .--------[1K]--------+---------+---{{{-----+
| \| / | | |
| ~~T~~ [LED] [LED] [LED]
| | | | |
| | [SCR1] [SCR2] [SCR8]
| | Pb1 /| /| /|
| | ___ | | | | | |
`-----------+--o o---[330]--+ +---------+---{{{-----+---+
| | | | | |
| | +--->|---------+ | | |
| | D1 | | | |
| | Pb2 | | | |
| | ___ | | | |
| +--o o---[330]------------+ | |
| | | | | |
| | +--->|---------+ | |
| | D2 | | |
((( {{{ {{{ {{{ {{{
| | | | |
| | Pb8 | | |
| | ___ | | |
| +--o o---[330]------------------{{{---+ |
| | | |
| +--->|---------+ |
| D8 | |
| | |
| || | |
`-->|--+--||--------------+ |
| ||100pF | |
| | |
[1K] [10K] |
| | |
Gnd --------------+------------------+-----------{{{---------+

I think the original poster wanted to control more than one LED
they could be wired in series and a higher voltage used.
If some mines contain more than 1 mineral, they can be
wired to multiple SCRs through diodes. Small signal diodes
like 1N4148s will be fine for that purpose. 1N4001's should
be used for the diodes connected to the pushbuttons.

4148's are ok for upto 200mA, they'd probably work everywhere


Bye.
Jasen
 
E

ehsjr

Jan 1, 1970
0
jasen said:
Ronald wrote:


+12 -----+------------------+---------+---{{{-----+
| | | |
| [LED] [LED] [LED]
| | | |
| [1K] [1K] [1K]
| | | |
| Pb1 [SCR1 [SCR2] [SCR8]
| ___ /| /| /|
+---o o---[330]--+ +---------+---{{{-----+---+
| | | | |
| +--->|---------+ | | |
| D1 | | | |
| Pb2 | | | |
| ___ | | | |
+---o o---[330]------------+ | |
| | | | |
| +--->|---------+ | |
| D2 | | |
{{{ {{{ {{{ {{{
| | | |
| Pb8 | | |
| ___ | | |
+---o o---[330]------------------------+ o
| | + |
+--->|---------+---[C1]----+----+ .->| N/C
D8 | | | |
+---[3.3K]--+ [RY1] o
| |
Gnd -------------------------------------------+---+


hey that's neat!


have you considered this.


+12 -+--. .--------[1K]--------+---------+---{{{-----+
| \| / | | |
| ~~T~~ [LED] [LED] [LED]
| | | | |
| | [SCR1] [SCR2] [SCR8]
| | Pb1 /| /| /|
| | ___ | | | | | |
`-----------+--o o---[330]--+ +---------+---{{{-----+---+
| | | | | |
| | +--->|---------+ | | |
| | D1 | | | |
| | Pb2 | | | |
| | ___ | | | |
| +--o o---[330]------------+ | |
| | | | | |
| | +--->|---------+ | |
| | D2 | | |
((( {{{ {{{ {{{ {{{
| | | | |
| | Pb8 | | |
| | ___ | | |
| +--o o---[330]------------------{{{---+ |
| | | |
| +--->|---------+ |
| D8 | |
| | |
| || | |
`-->|--+--||--------------+ |
| ||100pF | |
| | |
[1K] [10K] |
| | |
Gnd --------------+------------------+-----------{{{---------+

I like your idea.
I think the original poster wanted to control more than one LED
they could be wired in series and a higher voltage used.

Yes, multiple LEDs. Each SCR can control 4 amps, so he can
wire as many LEDs as he needs to each. The schematic didn't
show multiples, for simplicity in drawing, but it was mentioned
in the text. The problem with going in series is not electronic -
it's logic. Only those mines that have the exact same minerals
can be in the series string, and if you make a mistake, you have
to re-design the LED circuit for that string and for some other
string. When you make a mistake with the single LED, it is a
simple fix - just connect it & its resistor to a different spot
through a steering diode. It doesn't affect other LEDs.
4148's are ok for upto 200mA, they'd probably work everywhere

Good point - makes more sense to use the same diode throughout.
Somehow I had it (erroneously) in mind that the 1N4148 was
good for 75 mA.

Ed
 
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