Stretch 0.5sec pulse to 6sec

amdx · Feb 2, 2013

I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819, probably
a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie and
shorts about 3.5v to ground.

The longer story;
This started with "Have 5v regulator need 9 volts"
That particular problem is solved. everything has good clean power.

I have a Harbor Freight *Driveway sensor.
The sensor triggers a receiver with RF.
The receiver in turn triggers the alert button on a **Walkie Talkie.
After a temporary install, I noted the Talkie alert signaled 10 times.
That is to much, three times is fine.
After trying several things to eliminate the 10 alerts, I finally
wrapped the walkie talkie in aluminum foil. Problem solved. I'll deal
with this later by putting the Harbor Freight receiver inside my boat
and the walkie talkie outside where it's RF can get out. (it's an all
Aluminum boat)
The 0.5 sec pulse causes one alert signal. A six second pulse causes
three alert signals. Perfect!

*
http://www.harborfreight.com/wireless-driveway-alert-system-93068.html

**
http://www.motorola.com/Business/US-EN/Business+Product+and+Services/Two-Way+Radios+-+Consumers/Talkabout+FV300+Two-Way+Radio_B2B_US_EN

Mikek

Jim Thompson · Feb 3, 2013

On Sat, 02 Feb 2013 17:21:40 -0600, amdx <amdx@knologynotthis.net>
wrote:

I have a 4 volt pulse that is 0.5 sec long.

Positive-going?

I need a 6 sec pulse that will switch a 2n3904.

I presume, then, also positive-going?

The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819, probably
a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie and
shorts about 3.5v to ground.

The longer story;
This started with "Have 5v regulator need 9 volts"
That particular problem is solved. everything has good clean power.

I have a Harbor Freight *Driveway sensor.
The sensor triggers a receiver with RF.
The receiver in turn triggers the alert button on a **Walkie Talkie.
After a temporary install, I noted the Talkie alert signaled 10 times.
That is to much, three times is fine.
After trying several things to eliminate the 10 alerts, I finally
wrapped the walkie talkie in aluminum foil. Problem solved. I'll deal
with this later by putting the Harbor Freight receiver inside my boat
and the walkie talkie outside where it's RF can get out. (it's an all
Aluminum boat)
The 0.5 sec pulse causes one alert signal. A six second pulse causes
three alert signals. Perfect!

*
http://www.harborfreight.com/wireless-driveway-alert-system-93068.html

**
http://www.motorola.com/Business/US-EN/Business+Product+and+Services/Two-Way+Radios+-+Consumers/Talkabout+FV300+Two-Way+Radio_B2B_US_EN

Mikek

amdx · Feb 3, 2013

On 2/2/2013 7:10 PM, Jim Thompson wrote:

On Sat, 02 Feb 2013 17:21:40 -0600, amdx <amdx@knologynotthis.net
wrote:

I have a 4 volt pulse that is 0.5 sec long.

Positive-going?

Yes.
I need a 6 sec pulse that will switch a 2n3904.

I presume, then, also positive-going?

You presume correctly.

But you already new that. ;-)
Mikek

amdx · Feb 3, 2013

On 2/2/2013 5:21 PM, amdx wrote:

I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819, probably
a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie and
shorts about 3.5v to ground.

I have breadboarded the two transistor, 555 circuit.
Three alert signals as wanted. I can wire it on a pcb
in the morning, if no one comes up with a simple RC one transistor
pulse stretcher. I couldn't make it work, maybe it can't be done.
Seems the timing would be difficult, but for my circuit 20% fluctuation
would be ok.
Mikek

Jasen Betts · Feb 3, 2013

On 2013-02-02, amdx <amdx@knologynotthis.net> wrote:

I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819, probably
a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie and
shorts about 3.5v to ground.

you can't just use the discharge pin of the 555 instead of the collector of the
2n2904? is 200mA not enough?

--
ââ 100% natural

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

Jamie · Feb 3, 2013

amdx wrote:

I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819, probably
a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie and
shorts about 3.5v to ground.

The longer story;
This started with "Have 5v regulator need 9 volts"
That particular problem is solved. everything has good clean power.

I have a Harbor Freight *Driveway sensor.
The sensor triggers a receiver with RF.
The receiver in turn triggers the alert button on a **Walkie Talkie.
After a temporary install, I noted the Talkie alert signaled 10 times.
That is to much, three times is fine.
After trying several things to eliminate the 10 alerts, I finally
wrapped the walkie talkie in aluminum foil. Problem solved. I'll deal
with this later by putting the Harbor Freight receiver inside my boat
and the walkie talkie outside where it's RF can get out. (it's an all
Aluminum boat)
The 0.5 sec pulse causes one alert signal. A six second pulse causes
three alert signals. Perfect!

*
http://www.harborfreight.com/wireless-driveway-alert-system-93068.html

**
http://www.motorola.com/Business/US-EN/Business+Product+and+Services/Two-Way+Radios+-+Consumers/Talkabout+FV300+Two-Way+Radio_B2B_US_EN

Mikek

|
===
GND
.-.
| |1MEG PTT load (Radio)
| | |
0.5s Pulse 1k '-' ||-+
___ | ||<-
-|___|-->|+-------+-+-----------+-||-+
+ |
1N914 + |
--- 10uf ===
--- GND
+
| Power NMOS or what ever
|
===
GND
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)

Depending on your Vgs(th) spec you use for the NMOS will determine
the time off delay, which is what I think you're after.

This is one should be ~ 5 to 6 secs.

I didn't do a sim on this, just used a calculator but it should be
close.
THe pulse should pull the output down fast and the off delay
will give you a slight ramp due to the way fets are biased and behave
when the drain starts to get higher in voltage than the gate. This
should work out.

The diode is there to prevent back drain from the pulse source.

Jamie

amdx · Feb 3, 2013

On 2/2/2013 7:38 PM, Jasen Betts wrote:

On 2013-02-02, amdx <amdx@knologynotthis.net> wrote:
I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819, probably
a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie and
shorts about 3.5v to ground.

you can't just use the discharge pin of the 555 instead of the collector of the
2n2904? is 200mA not enough?

Do you mean the discharge (pin 2) or output (pin 3).

The pin from the walkie talkie already has a voltage on
it, pin 3 will source current to the walkie talkie before
it sinks current. I need an open collector to pull the Walkie talkie
low. That's my understanding for now.
Mikek

Jamie · Feb 3, 2013

amdx wrote:

On 2/2/2013 7:38 PM, Jasen Betts wrote:

On 2013-02-02, amdx <amdx@knologynotthis.net> wrote:

I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819, probably
a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie and
shorts about 3.5v to ground.

you can't just use the discharge pin of the 555 instead of the
collector of the
2n2904? is 200mA not enough?

Do you mean the discharge (pin 2) or output (pin 3).
The pin from the walkie talkie already has a voltage on
it, pin 3 will source current to the walkie talkie before
it sinks current. I need an open collector to pull the Walkie talkie
low. That's my understanding for now.
Mikek

if you drive the trigger input via the output of the timer through a
R of lets say 100k for example. Connect a 50uf cap from the trigger
input pin to common and then use a diode in parallel with the 100k R
to quickly recharge the cap when the output is high. The anode of the
diode will be on the output while the cathode is on the trigger input.

WIth this configuration, you can drive the threshold pin from your 4
volt source for the TX PTT signal. This will force both the output pin
to go low along with the discharge pin also going low. Take your pick
which one you want to use. I would use the discharge pin since it is a
open collector and not yet in use. The output pin will be busy
discharging the cap so the trigger input will reset the output when it
reaches 1/3 of the Vcc voltage.

And that is another issue. Since you only have 4 volts to drive the
threshold pin for the TX signal, your Vcc can not exceed 6 volts abs which
is on the edge, I would use a common 5 volt post reg to be sure for the
vcc.

The diode that is placed there for quick reset can be tailored with
adding a R in series with it if you don't want it respond to another
input pulse too early.. THat is up to you.

THis is just my opinion of course... others most likely have other ideas.

Jamie

amdx · Feb 3, 2013

On 2/2/2013 8:42 PM, Jamie wrote:

amdx wrote:

I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

|
===
GND
.-.
| |1MEG PTT load (Radio)
| | |
0.5s Pulse 1k '-' ||-+
___ | ||<-
-|___|-->|+-------+-+-----------+-||-+
+ |
1N914 + |
--- 10uf ===
--- GND
+
| Power NMOS or what ever
|
===
GND
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)

Depending on your Vgs(th) spec you use for the NMOS will determine
the time off delay, which is what I think you're after.

This is one should be ~ 5 to 6 secs.

I didn't do a sim on this, just used a calculator but it should be
close.
THe pulse should pull the output down fast and the off delay
will give you a slight ramp due to the way fets are biased and behave
when the drain starts to get higher in voltage than the gate. This
should work out.

The diode is there to prevent back drain from the pulse source.

Jamie

Thanks Jamie,

That seems to be working well. I have it breadboarded using 500k and
47uf with an IRFBE30* MOSFET, because that's what I have.
I'll work with it a bit more to get me centered between 2 alerts and 4
alerts. Right now it is alerting 3 times but I don't know if it is
centered between 2 and 4 alerts.
This will fit better in the case.
Thanks again, Mikek

Went back to the bench with a 1 meg pot, Found two alerts at 344k and 4
at 513k, centered at 428k and it consistently alerts 3 times. (47uf)

* IRFBE30 800V 30amp 3 ohm on resistance. Overkill but I have it.

Jim Thompson · Feb 3, 2013

On Sun, 03 Feb 2013 11:02:01 -0600, amdx <amdx@knologynotthis.net>
wrote:

On 2/2/2013 8:42 PM, Jamie wrote:
amdx wrote:

I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

|
===
GND
.-.
| |1MEG PTT load (Radio)
| | |
0.5s Pulse 1k '-' ||-+
___ | ||<-
-|___|-->|+-------+-+-----------+-||-+
+ |
1N914 + |
--- 10uf ===
--- GND
+
| Power NMOS or what ever
|
===
GND
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)

Depending on your Vgs(th) spec you use for the NMOS will determine
the time off delay, which is what I think you're after.

This is one should be ~ 5 to 6 secs.

I didn't do a sim on this, just used a calculator but it should be
close.
THe pulse should pull the output down fast and the off delay
will give you a slight ramp due to the way fets are biased and behave
when the drain starts to get higher in voltage than the gate. This
should work out.

The diode is there to prevent back drain from the pulse source.

Jamie

Thanks Jamie,
That seems to be working well. I have it breadboarded using 500k and
47uf with an IRFBE30* MOSFET, because that's what I have.
I'll work with it a bit more to get me centered between 2 alerts and 4
alerts. Right now it is alerting 3 times but I don't know if it is
centered between 2 and 4 alerts.
This will fit better in the case.
Thanks again, Mikek

Went back to the bench with a 1 meg pot, Found two alerts at 344k and 4
at 513k, centered at 428k and it consistently alerts 3 times. (47uf)

* IRFBE30 800V 30amp 3 ohm on resistance. Overkill but I have it.

Isn't a "Lert" some kind of bird ?>:-}

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice

Tim Wescott · Feb 4, 2013

On Sat, 02 Feb 2013 17:21:40 -0600, amdx wrote:

I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819, probably
a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie and
shorts about 3.5v to ground.

The longer story;
This started with "Have 5v regulator need 9 volts"
That particular problem is solved. everything has good clean power.

I have a Harbor Freight *Driveway sensor.
The sensor triggers a receiver with RF.
The receiver in turn triggers the alert button on a **Walkie Talkie.
After a temporary install, I noted the Talkie alert signaled 10 times.
That is to much, three times is fine.
After trying several things to eliminate the 10 alerts, I finally
wrapped the walkie talkie in aluminum foil. Problem solved. I'll deal
with this later by putting the Harbor Freight receiver inside my boat
and the walkie talkie outside where it's RF can get out. (it's an all
Aluminum boat)
The 0.5 sec pulse causes one alert signal. A six second pulse causes
three alert signals. Perfect!

74<your choice>123

Nice chip. You choose between positive- and negative-going pulses in and
out.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

amdx · Feb 4, 2013

On 2/3/2013 6:35 PM, Tim Wescott wrote:

On Sat, 02 Feb 2013 17:21:40 -0600, amdx wrote:

I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819, probably
a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie and
shorts about 3.5v to ground.

The longer story;
This started with "Have 5v regulator need 9 volts"
That particular problem is solved. everything has good clean power.

I have a Harbor Freight *Driveway sensor.
The sensor triggers a receiver with RF.
The receiver in turn triggers the alert button on a **Walkie Talkie.
After a temporary install, I noted the Talkie alert signaled 10 times.
That is to much, three times is fine.
After trying several things to eliminate the 10 alerts, I finally
wrapped the walkie talkie in aluminum foil. Problem solved. I'll deal
with this later by putting the Harbor Freight receiver inside my boat
and the walkie talkie outside where it's RF can get out. (it's an all
Aluminum boat)
The 0.5 sec pulse causes one alert signal. A six second pulse causes
three alert signals. Perfect!

74<your choice>123

Nice chip. You choose between positive- and negative-going pulses in and
out.

Jamie's RC, power FET circuit worked good and fit easily, no power
supply needed, only 5 parts.

Bonus, I had all the parts.
I'm in Panama City Fl. The highway doesn't make it here. We are at
the end of the line. Nothing goes past us to get somewhere. I have a
radio Shack and a one man audio repair shop, that sells some parts.
Thanks, Mikek

Feb 4, 2013

On Sun, 03 Feb 2013 19:25:55 -0600, amdx <amdx@knologynotthis.net>
wrote:

On 2/3/2013 6:35 PM, Tim Wescott wrote:
On Sat, 02 Feb 2013 17:21:40 -0600, amdx wrote:

I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819, probably
a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie and
shorts about 3.5v to ground.

The longer story;
This started with "Have 5v regulator need 9 volts"
That particular problem is solved. everything has good clean power.

I have a Harbor Freight *Driveway sensor.
The sensor triggers a receiver with RF.
The receiver in turn triggers the alert button on a **Walkie Talkie.
After a temporary install, I noted the Talkie alert signaled 10 times.
That is to much, three times is fine.
After trying several things to eliminate the 10 alerts, I finally
wrapped the walkie talkie in aluminum foil. Problem solved. I'll deal
with this later by putting the Harbor Freight receiver inside my boat
and the walkie talkie outside where it's RF can get out. (it's an all
Aluminum boat)
The 0.5 sec pulse causes one alert signal. A six second pulse causes
three alert signals. Perfect!

74<your choice>123

Nice chip. You choose between positive- and negative-going pulses in and
out.

Not so great with that kind of delay.

Jamie's RC, power FET circuit worked good and fit easily, no power
supply needed, only 5 parts.

Bonus, I had all the parts.
I'm in Panama City Fl. The highway doesn't make it here. We are at
the end of the line. Nothing goes past us to get somewhere. I have a
radio Shack and a one man audio repair shop, that sells some parts.

I'll bet even DigiKey (via UPS) ships to that end of the line. ;-)

amdx · Feb 4, 2013

On 2/3/2013 7:32 PM, krw@attt.bizz wrote:

On Sun, 03 Feb 2013 19:25:55 -0600, amdx <amdx@knologynotthis.net
wrote:

On 2/3/2013 6:35 PM, Tim Wescott wrote:
On Sat, 02 Feb 2013 17:21:40 -0600, amdx wrote:

I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819, probably
a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie and
shorts about 3.5v to ground.

The longer story;
This started with "Have 5v regulator need 9 volts"
That particular problem is solved. everything has good clean power.

I have a Harbor Freight *Driveway sensor.
The sensor triggers a receiver with RF.
The receiver in turn triggers the alert button on a **Walkie Talkie.
After a temporary install, I noted the Talkie alert signaled 10 times.
That is to much, three times is fine.
After trying several things to eliminate the 10 alerts, I finally
wrapped the walkie talkie in aluminum foil. Problem solved. I'll deal
with this later by putting the Harbor Freight receiver inside my boat
and the walkie talkie outside where it's RF can get out. (it's an all
Aluminum boat)
The 0.5 sec pulse causes one alert signal. A six second pulse causes
three alert signals. Perfect!

74<your choice>123

Nice chip. You choose between positive- and negative-going pulses in and
out.

Not so great with that kind of delay.

Jamie's RC, power FET circuit worked good and fit easily, no power
supply needed, only 5 parts.

Bonus, I had all the parts.
I'm in Panama City Fl. The highway doesn't make it here. We are at
the end of the line. Nothing goes past us to get somewhere. I have a
radio Shack and a one man audio repair shop, that sells some parts.

I'll bet even DigiKey (via UPS) ships to that end of the line. ;-)

Sure.

But I want it now!

Mikek

Tim Wescott · Feb 4, 2013

On Sun, 03 Feb 2013 20:32:05 -0500, krw wrote:

On Sun, 03 Feb 2013 19:25:55 -0600, amdx <amdx@knologynotthis.net
wrote:

On 2/3/2013 6:35 PM, Tim Wescott wrote:
On Sat, 02 Feb 2013 17:21:40 -0600, amdx wrote:

I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819,
probably a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie
and
shorts about 3.5v to ground.

The longer story;
This started with "Have 5v regulator need 9 volts"
That particular problem is solved. everything has good clean power.

I have a Harbor Freight *Driveway sensor.
The sensor triggers a receiver with RF.
The receiver in turn triggers the alert button on a **Walkie Talkie.
After a temporary install, I noted the Talkie alert signaled 10
times.
That is to much, three times is fine.
After trying several things to eliminate the 10 alerts, I finally
wrapped the walkie talkie in aluminum foil. Problem solved. I'll deal
with this later by putting the Harbor Freight receiver inside my boat
and the walkie talkie outside where it's RF can get out. (it's an all
Aluminum boat)
The 0.5 sec pulse causes one alert signal. A six second pulse causes
three alert signals. Perfect!

74<your choice>123

Nice chip. You choose between positive- and negative-going pulses in
and out.

Not so great with that kind of delay.

Jamie's RC, power FET circuit worked good and fit easily, no power
supply needed, only 5 parts.

Bonus, I had all the parts.
I'm in Panama City Fl. The highway doesn't make it here. We are at
the end of the line. Nothing goes past us to get somewhere. I have a
radio Shack and a one man audio repair shop, that sells some parts.

I'll bet even DigiKey (via UPS) ships to that end of the line. ;-)

Six seconds. Hmm. Good point. Of course, nothing that's RC-based is
going to really be solid at that delay. For what he wants, though, any
halfway decent approximation to six seconds ought to be OK.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

Michael A. Terrell · Feb 4, 2013

amdx wrote:

krw@attt.bizz wrote:

I'll bet even DigiKey (via UPS) ships to that end of the line. ;-)

Sure.
But I want it now!

Move to Thief River Falls.

Jasen Betts · Feb 4, 2013

On 2013-02-03, amdx <amdx@knology.net> wrote:

On 2/2/2013 7:38 PM, Jasen Betts wrote:
On 2013-02-02, amdx <amdx@knologynotthis.net> wrote:
I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819, probably
a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie and
shorts about 3.5v to ground.

you can't just use the discharge pin of the 555 instead of the collector of the
2n2904? is 200mA not enough?

Do you mean the discharge (pin 2) or output (pin 3).
The pin from the walkie talkie already has a voltage on
it, pin 3 will source current to the walkie talkie before
it sinks current. I need an open collector to pull the Walkie talkie
low. That's my understanding for now.
Mikek

pin 2 is trigger one of the main inputs.

Discharge is an open collector output it's on pin 7

--
ââ 100% natural

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

Feb 4, 2013

On Sun, 03 Feb 2013 22:08:20 -0600, Tim Wescott
<tim@seemywebsite.please> wrote:

On Sun, 03 Feb 2013 20:32:05 -0500, krw wrote:

On Sun, 03 Feb 2013 19:25:55 -0600, amdx <amdx@knologynotthis.net
wrote:

On 2/3/2013 6:35 PM, Tim Wescott wrote:
On Sat, 02 Feb 2013 17:21:40 -0600, amdx wrote:

I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819,
probably a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie
and
shorts about 3.5v to ground.

The longer story;
This started with "Have 5v regulator need 9 volts"
That particular problem is solved. everything has good clean power.

I have a Harbor Freight *Driveway sensor.
The sensor triggers a receiver with RF.
The receiver in turn triggers the alert button on a **Walkie Talkie.
After a temporary install, I noted the Talkie alert signaled 10
times.
That is to much, three times is fine.
After trying several things to eliminate the 10 alerts, I finally
wrapped the walkie talkie in aluminum foil. Problem solved. I'll deal
with this later by putting the Harbor Freight receiver inside my boat
and the walkie talkie outside where it's RF can get out. (it's an all
Aluminum boat)
The 0.5 sec pulse causes one alert signal. A six second pulse causes
three alert signals. Perfect!

74<your choice>123

Nice chip. You choose between positive- and negative-going pulses in
and out.

Not so great with that kind of delay.

Jamie's RC, power FET circuit worked good and fit easily, no power
supply needed, only 5 parts.

Bonus, I had all the parts.
I'm in Panama City Fl. The highway doesn't make it here. We are at
the end of the line. Nothing goes past us to get somewhere. I have a
radio Shack and a one man audio repair shop, that sells some parts.

I'll bet even DigiKey (via UPS) ships to that end of the line. ;-)

Six seconds. Hmm. Good point. Of course, nothing that's RC-based is
going to really be solid at that delay. For what he wants, though, any
halfway decent approximation to six seconds ought to be OK.

It's way off (three orders of magnitude off) the chart for the HC
types, at least according to TI. This sort of thing is right up the
alley for a 555, though.

Jim Thompson · Feb 4, 2013

On Sat, 02 Feb 2013 17:21:40 -0600, amdx <amdx@knologynotthis.net>
wrote:

I have a 4 volt pulse that is 0.5 sec long.
I need a 6 sec pulse that will switch a 2n3904.
The 4 volts has about a 400 ohm source impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555, so
maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819, probably
a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie and
shorts about 3.5v to ground.

The longer story;
This started with "Have 5v regulator need 9 volts"
That particular problem is solved. everything has good clean power.

I have a Harbor Freight *Driveway sensor.
The sensor triggers a receiver with RF.
The receiver in turn triggers the alert button on a **Walkie Talkie.
After a temporary install, I noted the Talkie alert signaled 10 times.
That is to much, three times is fine.
After trying several things to eliminate the 10 alerts, I finally
wrapped the walkie talkie in aluminum foil. Problem solved. I'll deal
with this later by putting the Harbor Freight receiver inside my boat
and the walkie talkie outside where it's RF can get out. (it's an all
Aluminum boat)
The 0.5 sec pulse causes one alert signal. A six second pulse causes
three alert signals. Perfect!

*
http://www.harborfreight.com/wireless-driveway-alert-system-93068.html

**
http://www.motorola.com/Business/US-EN/Business+Product+and+Services/Two-Way+Radios+-+Consumers/Talkabout+FV300+Two-Way+Radio_B2B_US_EN

Mikek

Sort of an off-the-wall thought...

Count the 'lerts >:-}

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice

Tim Wescott · Feb 4, 2013

On Mon, 04 Feb 2013 12:36:38 -0500, krw wrote:

On Sun, 03 Feb 2013 22:08:20 -0600, Tim Wescott
tim@seemywebsite.please> wrote:

On Sun, 03 Feb 2013 20:32:05 -0500, krw wrote:

On Sun, 03 Feb 2013 19:25:55 -0600, amdx <amdx@knologynotthis.net
wrote:

On 2/3/2013 6:35 PM, Tim Wescott wrote:
On Sat, 02 Feb 2013 17:21:40 -0600, amdx wrote:

I have a 4 volt pulse that is 0.5 sec long. I need a 6 sec pulse
that will switch a 2n3904. The 4 volts has about a 400 ohm source
impedance.

I could use a 555, but first I need to invert the signal then
drive my 2n3904 switch, so I have 2 transistors and a 555. Oh yes I
could probably differentiate the 0.5 sec pulse to trigger the 555,
so maybe only 1 transistor and a 555.

Could someone help with a pulse stretcher circuit.
Maybe an RC, transistor, or, I have some FETs, J301 or 2N3819,
probably a diode. That will drive my final 2N3904 switch.
The 2N3904 switch is across the alert button on a Walkie Talkie
and
shorts about 3.5v to ground.

The longer story;
This started with "Have 5v regulator need 9 volts"
That particular problem is solved. everything has good clean power.

I have a Harbor Freight *Driveway sensor. The sensor triggers a
receiver with RF. The receiver in turn triggers the alert button on
a **Walkie Talkie. After a temporary install, I noted the Talkie
alert signaled 10 times.
That is to much, three times is fine. After trying several
things to eliminate the 10 alerts, I finally
wrapped the walkie talkie in aluminum foil. Problem solved. I'll
deal with this later by putting the Harbor Freight receiver inside
my boat and the walkie talkie outside where it's RF can get out.
(it's an all Aluminum boat)
The 0.5 sec pulse causes one alert signal. A six second pulse
causes three alert signals. Perfect!

74<your choice>123

Nice chip. You choose between positive- and negative-going pulses
in and out.

Not so great with that kind of delay.

Jamie's RC, power FET circuit worked good and fit easily, no power
supply needed, only 5 parts.

Bonus, I had all the parts.
I'm in Panama City Fl. The highway doesn't make it here. We are at
the end of the line. Nothing goes past us to get somewhere. I have a
radio Shack and a one man audio repair shop, that sells some parts.

I'll bet even DigiKey (via UPS) ships to that end of the line. ;-)

Six seconds. Hmm. Good point. Of course, nothing that's RC-based is
going to really be solid at that delay. For what he wants, though, any
halfway decent approximation to six seconds ought to be OK.

It's way off (three orders of magnitude off) the chart for the HC types,
at least according to TI. This sort of thing is right up the alley for
a 555, though.

So extend the charts!!

The delay time of a 74HC123 is roughly one RC time constant, you don't
want the resistance to be too low and if it gets too high then you have
to contend with board or capacitor leakage. The delay time of a 555 is
roughly the same, but you don't have the flexibility of input and output.

Either chip demands that you select a big, low-leakage cap, and a high
resistance, and accept the fact that your leakage is going to vary with
temperature and humidity. Understand that you'll wish that you had done
something with a counter from the git-go, and build your circuit.

I _think_ you could do this more reliably with a CD4060 and a dual J-K
flip-flop, or a 555, a CD4040, and that same J-K flip-flop, but I'd have
to toy with it to be sure and I don't think I care enough to try.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

Stretch 0.5sec pulse to 6sec

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