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!)
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