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I want to build a simple circuit that will turn off a 120 volt light
for 5 minutes when my bird is too noisy. After that I would like the
light to go back on. Can anyone help or direct me to best newsgroup?
.... or for something in between, the PICAXE might handle this & be fun"gina" <led@bigstring.com> wrote in message
news:e17f3200-7262-41ff-a419-c10453cbad1b@c19g2000prf.googlegroups.com...
I want to build a simple circuit that will turn off a 120 volt light
for 5 minutes when my bird is too noisy. After that I would like the
light to go back on. Can anyone help or direct me to best newsgroup?
how involved can you get? Do you know how to get parts, and solder a
simple circuit? Or, do you want an off-the-shelf solution?
If you can build circuits, you can use a relay, an electret microphone,
a transistor, and a 555 monostable (along with a few resistors and
capacitors) to build something that would work.
If you are interested in a circuit to build, please reply here.
Regards
Bob Monsen
Hotwire one of those clap on clap off things.I want to build a simple circuit that will turn off a 120 volt light
for 5 minutes when my bird is too noisy. After that I would like the
light to go back on. Can anyone help or direct me to best newsgroup?
I can solder but I have never built a circuit. If it's fairly easy I"gina" <l...@bigstring.com> wrote in message
news:e17f3200-7262-41ff-a419-c10453cbad1b@c19g2000prf.googlegroups.com...
I want to build a simple circuit that will turn off a 120 volt light
for 5 minutes when my bird is too noisy. After that I would like the
light to go back on. Can anyone help or direct me to best newsgroup?
how involved can you get? Do you know how to get parts, and solder a simple
circuit? Or, do you want an off-the-shelf solution?
If you can build circuits, you can use a relay, an electret microphone, a
transistor, and a 555 monostable (along with a few resistors and capacitors)
to build something that would work.
If you are interested in a circuit to build, please reply here.
Regards
Bob Monsen
(First, read this message in courier font, because there are ascii diagrams"gina" <led@bigstring.com> wrote in message
news:d6cf05ed-750c-4972-b4f0-4835fb67c408@b64g2000hsa.googlegroups.com...
On Apr 13, 9:07 pm, "Bob Monsen" <rcmon...@gmail.com> wrote:
"gina" <l...@bigstring.com> wrote in message
news:e17f3200-7262-41ff-a419-c10453cbad1b@c19g2000prf.googlegroups.com...
I want to build a simple circuit that will turn off a 120 volt light
for 5 minutes when my bird is too noisy. After that I would like the
light to go back on. Can anyone help or direct me to best newsgroup?
how involved can you get? Do you know how to get parts, and solder a
simple
circuit? Or, do you want an off-the-shelf solution?
If you can build circuits, you can use a relay, an electret microphone,
a
transistor, and a 555 monostable (along with a few resistors and
capacitors)
to build something that would work.
If you are interested in a circuit to build, please reply here.
Regards
Bob Monsen
I can solder but I have never built a circuit. If it's fairly easy I
would love to give it a try. Can you get me started? Thanks gina
Wow, nice work Bob."gina" <l...@bigstring.com> wrote in message
news:d6cf05ed-750c-4972-b4f0-4835fb67c408@b64g2000hsa.googlegroups.com...
On Apr 13, 9:07 pm, "Bob Monsen" <rcmon...@gmail.com> wrote:
"gina" <l...@bigstring.com> wrote in message
news:e17f3200-7262-41ff-a419-c10453cbad1b@c19g2000prf.googlegroups.com...
I want to build a simple circuit that will turn off a 120 volt light
for 5 minutes when my bird is too noisy. After that I would like the
light to go back on. Can anyone help or direct me to best newsgroup?
how involved can you get? Do you know how to get parts, and solder a
simple
circuit? Or, do you want an off-the-shelf solution?
If you can build circuits, you can use a relay, an electret microphone,
a
transistor, and a 555 monostable (along with a few resistors and
capacitors)
to build something that would work.
If you are interested in a circuit to build, please reply here.
Regards
Bob Monsen
I can solder but I have never built a circuit. If it's fairly easy I
would love to give it a try. Can you get me started? Thanks gina
(First, read this message in courier font, because there are ascii diagrams
in it, which will make no sense
unless you are reading them with a fixed width font.)
Here is what you need:
The power supply:
1 12V DC wall adapter. Only needs to support about 100mA (more is fine). The
cheaper, the better.
1 7805 integrated circuit
1 0.1uF (uF stands for microfarad) capacitor (10V minimum rating)
1 0.33uF (25V minimum rating) capacitor.
1 1N4148 diode (or any old diode, it does not matter much)
The sound detector:
1 electret microphone
1 15k Ohm resistor
1 2N3904 NPN transistor (or equivalent, small signal transistor, three
terminals)
1 1Meg Ohm resistor
1 10k Ohm resistor (10,000 ohms)
1 0.1uF capacitor
The timing element:
1 cmos 555 integrated circuit (see here for more info:http://en.wikipedia.org/wiki/555_timer_IC)
1 220uF electrolytic capacitor (6.8V or higher voltage rating)
1 1Meg Ohm resistor
1 0.1uF capacitor (6.8V or higher voltage rating)
Connecting the detector to the timing element:
1 1uF capacitor
1 220k variable resistor trimmer you can set with a screwdriver
The light switch:
1 12V 'normally closed' relay that can handle the
current for your light bulb. A 220V/1A
capable relay should do it easily.
1 2N3904 NPN transistor (or equivalent)
1 1k resistor
1 1N4001 diode (or equivalent)
The circuit board:
1 prototyping board you can solder everything to. I like 'stripboard' for
this kind of thing.
http://www.futurlec.com/ProtoBoards.shtml
Tools:
wire cutters
a digital multimeter
a soldering iron + solder
1 1k resistor
1 cheapo red LED
a tool to trim leads (wire cutters, but must be able to cut things very
short)
-------------------------------------------------
Step 1: the power supply
Diode
.------|<-------.
| |
| |
| ____ |
12V | | | |
voltage + o----o----|7805|-----o----------------- 5V
| |____| |
| | |
0.33uF --- | --- 0.1uF
cap --- | --- cap
| | |
| | |
voltage -------o------o--------o----------------- ground
0V
.---------.
| 0 |
| |
|---------|
| |
| LM7805 |
| |
| |
'---------'
| | |
| | |
| | |
| | |
| | |
in g out
(created by AACircuit v1.28.6 beta 04/19/05www.tech-chat.de)
Take the wall transformer. There is a wall plug of some kind coming out of
it, and another wire coming out of it. That other wire gives you the 12V (or
more).
Note that the voltage coming out of the thing is not dangerous, but you
should respect it, and not short circuit the output while the thing is
plugged in, since they often have internal fuses which will blow if you do
this, and you'll need to get another one.
Cut off the 12V plug (not the two pronged plug, but the other one that you
would normally plug into a device to power it) coming out of the
transformer, and strip the wires about 1/2 inch with the wirecutters. Solder
the wires to the prototype board on different pads. The pads should be
isolated from one another, so if you use a stripboard, use a different strip
for this.
Now, determine which wire is + and which is - by carefully plugging in the
transformer, and using your multimeter to measure the voltage. If it reads
0, either the transformer is defective, or it is an AC transformer. In
either case, you need another one.
One way you measure it the multimeter will read something like 12V. The
other way, it'll read -12V. For the +12V case, the black probe is now
touching the - output, and the red probe is now touching the + output. Mark
these on the top of the board somehow so you don't get them confused.
Solder the 0.33uF capacitor between these leads. (If you got one that looks
like a little can with two leads, and has a little + and - on it, that is
called an electrolytic capcitor.) Make sure it can handle at least 25V, as
stated above. Solder the - lead (or one of the leads if there isn't a + or -
on it) to the prototboard so it will connect to the minus power input from
the transformer. Solder the other lead to the +12V input.
Now, connect up the 7805. If you hold it by the silver tab, so the writing
is visible, the leads are left = input, middle = ground, right = output. So,
connect up the left to the +12V, and the ground to the - input. Now, connect
the 0.1uF capacitor between the center and right lead. Connect the diode
from the right lead to the left lead, so that the line painted on the diode
is nearer to the left side.
The -|<- is a diode, which lets current flow from right to left if right is
higher than left. This is there to protect the LM7805, which will fail if
you put voltage across it the wrong way.
So, now you've built a power supply. You should test it. Use the 1k resistor
as a test part, and connect it between the Right and Center leads of the
LM7805. Power it up by plugging it in. Keep you finger on the diode. If it
starts to heat up, unplug it immediately, and figure out how you screwed up.
If it does not heat up, measure the voltage between the left and center pin
with your multimeter. If it is 5V, you are a winner! You now have a
combination 12V unregulated, 5V regulated power supply.
Unplug the adapter.
Step 2: the sound detector
5V -----------o------------------.
| |
.-. .-. .-------.
| | 22k | | 10k | |
| | | | | 2N |
'-' '-' | 3904 |
| || ___ | | |
o--||---o--|___|---o- to 555 '-------'
| || | 1 MEG |c | | |
| 0.1uF | |/ | | |
| '------b-| | | |
| |> e | | |
|---. | | | | |
| |--' | | | |
| |--. | | | |
|---' | | | | |
GND ----------o------------------' e b c
(created by AACircuit v1.28.6 beta 04/19/05www.tech-chat.de)
Take the electret microphone, and look at it. One of the leads is visibly
electrically connected (shorted) to the case, and one is isolated from the
case. The one that is shorted to the case is the 'ground' lead. The other
lead is the 'output' lead.
(NOTE: In our system, we are using the minus side of the wall adapter as
ground. I'll refer to in as ground from now on. Nearly everything will
somehow connect to ground, which forms a return for the electricity flowing
out of the adapter and through the circuit.)
The electret microphone is really both a microphone and an amplifier put
together. When the other lead of the microphone (the one NOT shorted to the
case) is powered with a current, the microphone turns sound into a variable
current draw. So, take the 15k resistor, and attach it to the right lead of
the LM7805. Lets call this "5V" from now on. Solder the other side of the
resistor to a pad on the protoboard, and connect that pad somehow to the
non-ground lead of the electret microphone. Connect the ground lead to
ground (ie, the center pin of the LM7805, which is also connected to the -
input of the wall adapter).
At this point, you have the microphone connected, and if you plugged it in,
it should be powered properly. Plug in the adapter, and measure the voltage
between the microphone and the 15k resistor. It should be between 2 and 3
volts. If not, there may be a problem. Electret microphones are not all that
consistent in how much current they take. If the microphone to resistor
junction is below 1V, then it is taking too much current. If it is above 4
voltages, it is taking too little. In either case, it won't work very well.
Try changing the value of the resistor by swapping out 4.7k, 10k, 15k, 22k,
etc, until it is near 2.5V. That is where you want it to be.
When it is powered and your multimeter is measuring the voltage from ground
to the microphone-resistor junction, try tapping on the electret. It should
just register a tiny bit.
Now, connect the + side of the electret microphone to one side of the 0.1uF
capacitor. Connect the other side of the 0.1uF capacitor to the base lead of
the NPN 2N3904. If you really have a 2N3904 and not another transistor, then
if you hold it so the pins are down, and you can read the writing on the
front, the pins are left = emitter, middle = base, right = collector. I'll
call them emitter, base, collector. So, connect the base to the other side
of the 0.1uF capacitor. Also connect the base to one side of the 1MEG
resistor. Connect the other side of that resistor to the collector. Now,
connect the collector to one side of the 10k resistor, and the other side of
the 10k resistor to 5V. Connect the emitter lead of the transistor to ground
(the - input, and middle pin of the LM7805).
NOTE: not all transistors have the same pin assignments. So, when you get
the transistor, read the number off the front, and then do a search on the
internet for that number. It is usually 2Nxxxx, where the x can be any
digit. Look at the datasheet for the transistor, and it'll tell you which
lead is the base, which is the emitter, and which is the collector.
Now, you have a microphone and an amplifier to amplify it. You should plug
it in again, and feel the parts to make sure none of them are getting hot.
If anything gets hot, unplug it now, because something is wrong. You should
analyze the circuit, and make sure you don't have things connected
improperly. One way to do this is to use the 'resistance' mode on your
multimeter to make sure the resistances in the circuit are as you expect
them to be. Another is to measure the voltages at various points, and ensure
that they are reasonable when it is plugged in. For example, the collector
of the NPN should be about 2.5V. If it is less than 1, or greater than 4,
something is wrong.
If everything seems ok, then connect the red probe of the multimeter to the
collector of the NPN, and the black probe to ground. The voltage should be
between 1 and 4 volts. Now, tap the microphone. You should see bigger
movements on the output of the multimeter than before when you do that. If
you don't see these, something is wrong. Go back and look it over.
Step 3: the timing element
5V
--------o-------------o------------------o------.
| | | |
| | | |
| | | .-.
| | | | | 1MEG
| | | | |
| | | '-'
From | | 555 | |
Detector | | __ | |
|| | .--)----o| |o--------' |
---||----)----o-----)--)----o| |o----------o----o
|| | | | | .--o| |o----------' |
0.1uF | | | '-)--o|__|o- |
.-. | | | |
220k | |<--' | | | +
variable| | '---------- to relay --- 220uF
'-' | section ---
| | |
| | |
| | |
---------o----------o----------------------------'
GND
(created by AACircuit v1.28.6 beta 04/19/05www.tech-chat.de)
You have the 555 in your hand, and you are looking at it. It looks like
somebody's idea of a joke bug, with its little metal legs. However, there
are literally billions of these little bugs in the world today, calmly
ticking away time. I believe it is the best selling integrated circuit every
built. If you are looking down on it, you'll notice there is a little area
cut out of the top of one side. If you hold it so that little cut is up, and
the pins are on the sides, then the top left pin is pin 1, and they
increase, going around the device till they get to pin 9 on the top right.
The diagram above is set up so it is arranged in the same way.
The circuit above will give you a long pulse (ie, a long 'high' value out of
pin 3) given a short downward pulse on pin 2 which is below 1.66 volts.
Most protoboards are designed to hold these. If you are using a stripboard
prototype board, then you'll need to cut the traces between the pins on the
right and the left. I use a dremel tool with a drill bit, but there are
other ways.
Now, connect the 5V to pin 8 and pin 4. Also, connect one side of the
variable resistor (the trimmer) to the 5V, and one side of the 1MEG
resistor. Connect the other side of the variabel resistor to ground, and the
middle pin, what is called the wiper, to the 0.1uF cap and pin 2. Connect
pin 1 to ground.
Solder the other side of the 1MEG resistor to pin 7, and short pin 7 and pin
6 together. Connect the positive side of the 220uF capacitor to that, and
the other side to ground.
The pulse will last for 1.1 * R * C, where R = 1,000,000, and C = 0.000220.
So, the result is about 242 seconds.
The variable resistor is there to control the sensitivity.
The output comes out on pin 3. That goes to the next section.
Step 4: The light switch
NOTE: This is the part that can kill you, so please be careful.
12V (NOTE)
---------o------.
| | --------------- to lamp
| | \
| |_ o o
diode - ' )|
^ )|
| _)|
'----.--- --------------- to lamp
|
|
1k | c
___ b |/
555--|___|----|
|
| e
|
|
GND -----------'
Not a good picture of a relay
You want a normally open relay, with two inputs and three outputs.
(created by AACircuit v1.28.6 beta 04/19/05www.tech-chat.de)
A relay is a switch, which is turned on or off with a little electromagnet.
They have two leads for the electromagnet, and two or three leads (or more)
for the switch leads. Your circuit is trying to turn off a light for a while
when it hears a loud sound, so it wants to be connected unless you power it.
So, find a relay that has a 12V coil, and that has three output leads.
Get an extension cord with two prongs, and split it apart a bit near the
wall plug end. Cut one of the wires. I'd suggest cutting the one attached to
the big prong, not the one attached to the small prong. However, it doesn't
really matter all that much.
Take your relay, and connect one side of the coil to the 12V input from the
wall adapter. Do not connect it to the 5V supply you built above, use the
input to that supply. Also, connect a diode in parallel across the coil,
with the line nearest to the 12V side. You can determine which are the coil
using your multimeter on resistance setting. It should have more than 100
but less than 1000 ohms of resistance between the two coil leads. The other
leads will have either very small or very large resistances.
Connect the other side of the coil to the collector of the NPN (which is the
same as the NPN above)
Connect the emitter of the npn to ground, and the base of the NPN through a
1k resistor to pin 3 on the 555.
Now, use your multimeter on the resistance setting to see which leads to
connect your extension cord to. It'll be the leads with almost 0 resistance
when the circuit is off.
Solder these to the relay. MAKE SURE that this part of the circuit is
electrically isolated from the rest. Wrap electricians tape around the
exposed wires, etc. Make sure it is not in a position to shake free and kill
you. Etc etc.
Step 5: test it out
Now, plug in the lamp to the extension cord. Plug in the adapter. Plug in
the extension cord. It should start out as being off. After about 4 minutes,
it should come on.
Now, bring over the parrot, and make it squawk near the thing. It'll turn
off if you are lucky.
You can adjust the sensitivity to parrot noise using the variable resistor
you soldered in in step 3. If it is too sensitive, it'll always be off. If
it isn't sensitive enough, it'll never turn off.
Have fun. Be careful.
Regards,
Bob Monsen
<snip>On Apr 21, 10:33 am, "Bob Monsen" <rcmon...@gmail.com> wrote:
Thanks. Seems like lots of people ask these kinds of questions, but haven'tHave fun. Be careful.
Regards,
Bob Monsen
Wow, nice work Bob.
That gets my vote for the comprehensive reply of the week!
Dave.
Holy Moly,"David L. Jones" <altz...@gmail.com> wrote in messagenews:0e05df19-a8dc-457f-9ae1-57b93dc740fc@y22g2000prd.googlegroups.com...
On Apr 21, 10:33 am, "Bob Monsen" <rcmon...@gmail.com> wrote:
snip
Have fun. Be careful.
Regards,
Bob Monsen
Wow, nice work Bob.
That gets my vote for the comprehensive reply of the week!
Dave.
Thanks. Seems like lots of people ask these kinds of questions, but haven't
a clue about where to start once they get the 'answer', which is mostly an
indecipherable ascii circuit diagram. So, I thought I'd try making it
easier. It took way longer than I expected to anticipate all the details and
type them in. I actually had to breadboard it as I was writing it.
Anyway, I hope it helps somebody get into the groove of hobbying with
electronics.
One thing I forgot was where to get the parts. I was assuming radio shack,
but I don't think they have a really good selection anymore. So, unless I've
scared off the OP, here is a list of mail-order places:
http://www.digikey.comhttp://www.mouser.comhttp://www.allelectronics.comhttp://www.jameco.comhttp://www.goldmine-elec.comhttp://www.futurlec.com