Laser question

[Martin Brown]

On 30/04/2019 19:18, AK wrote:

On Tuesday, April 30, 2019 at 1:12:43 PM UTC-5, Clive Arthur wrote:
On Tuesday, April 30, 2019 at 11:56:27 AM UTC-5, George Herold wrote:

snipped

Ahh.. OK those specs look nothing like you first posted.
I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

George H.

Looks like this is the one the OP meant, though the data sheet doesn't
agree with the specs...

https://www.jameco.com/z/104990022-Seeed-Studios-5mW-Laser-Module-Emitter-Red-Dot-Adjustable-Lens_2217692.html

So the OP posts a link to the wrong device, and the supplier prints
different specs to that device's data sheet. I don't see this ending well.

Cheers
--
Clive

No, this is what I will use as it is much cheaper than the adjustable one.

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

That is a bare laser LED and needs something approximating a constant
current driver and a DC supply applied the right way round. I expect
laser diodes to be more tetchy than LEDs about reverse voltages too.

--
Regards,
Martin Brown

 

[AK]

On Tuesday, April 30, 2019 at 2:32:58 PM UTC-5, George Herold wrote:

On Tuesday, April 30, 2019 at 3:11:37 PM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 1:30:17 PM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 2:02:45 PM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 11:56:27 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 11:21:18 AM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 8:29:22 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.
GH

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

Ahh.. OK those specs look nothing like you first posted.
I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

George H.

Could you give some details on that?

Thanks,
Andy

googles, lm317 current source
http://www.bristolwatch.com/ccs/LM317.htm

GH
Not so good fro small currents but perfect for 10-100mA

+Vcc -------LM 317------10 ohm resistor-----lout
|
.1 uF capacitor

I have a 5 volt power transformer.

Do I get it down to 3 volts first?

Then connect positive to Vcc ?

Does the negative go straight to the laser diode while lout goes to the positive lead of the laser?

Andy

Hmm, well definitely buy more than one laser diode...
'cause I'm guessing you will blow some.
You could put a few 1n4002 in series and use those for a dummy
laser diode.
Read that whole page on LM317 current sources... Make sure
you understand how to choose all the values.
(There is a connection from the output to the adjust pin of lm317)

Maybe read some about how the lm317 works.
10 ohms gives you 120 mA how much current do you want?

George H.

This is becoming quite a complicated project.

I can buy a laser with it's own power supply, but I would prefer building my own.

This is it's specs. Should I be looking at the working current?

Material: Plastic and copper
Operating Voltage: 3V DC
Working current: < 40mA
Input power: 150mW
With red dot
Wavelength: 650nm
Output laser power: < 5mW

 

[Clive Arthur]

On 30/04/2019 19:18, AK wrote:

On Tuesday, April 30, 2019 at 1:12:43 PM UTC-5, Clive Arthur wrote:
On Tuesday, April 30, 2019 at 11:56:27 AM UTC-5, George Herold wrote:

snipped

Ahh.. OK those specs look nothing like you first posted.
I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

George H.

Looks like this is the one the OP meant, though the data sheet doesn't
agree with the specs...

https://www.jameco.com/z/104990022-Seeed-Studios-5mW-Laser-Module-Emitter-Red-Dot-Adjustable-Lens_2217692.html

So the OP posts a link to the wrong device, and the supplier prints
different specs to that device's data sheet. I don't see this ending well.

Cheers
--
Clive

No, this is what I will use as it is much cheaper than the adjustable one.

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

That device doesn't have either the specs or the description you posted.
You made a mistake, we all do.

Cheers
--
Clive

 

[whit3rd]

On Tuesday, April 30, 2019 at 9:56:27 AM UTC-7, George Herold wrote:

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

The LM317 current source will work, but the dropout voltage
is better if you use a TLV431 and NPN transistor for low-side
current limiter.

 

[George Herold]

On Tuesday, April 30, 2019 at 4:18:57 PM UTC-4, AK wrote:

On Tuesday, April 30, 2019 at 2:32:58 PM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 3:11:37 PM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 1:30:17 PM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 2:02:45 PM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 11:56:27 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 11:21:18 AM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 8:29:22 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.
GH

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

Ahh.. OK those specs look nothing like you first posted.
I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

George H.

Could you give some details on that?

Thanks,
Andy

googles, lm317 current source
http://www.bristolwatch.com/ccs/LM317.htm

GH
Not so good fro small currents but perfect for 10-100mA

+Vcc -------LM 317------10 ohm resistor-----lout
|
.1 uF capacitor

I have a 5 volt power transformer.

Do I get it down to 3 volts first?

Then connect positive to Vcc ?

Does the negative go straight to the laser diode while lout goes to the positive lead of the laser?

Andy

Hmm, well definitely buy more than one laser diode...
'cause I'm guessing you will blow some.
You could put a few 1n4002 in series and use those for a dummy
laser diode.
Read that whole page on LM317 current sources... Make sure
you understand how to choose all the values.
(There is a connection from the output to the adjust pin of lm317)

Maybe read some about how the lm317 works.
10 ohms gives you 120 mA how much current do you want?

George H.

This is becoming quite a complicated project.

I can buy a laser with it's own power supply, but I would prefer building my own.

Well as others have said upstream, the simplest current source is a
voltage source and the right resistor. I think you should start there.
Do you have a DMM voltmeter?
Get a 12V (or other) wall wart, and calculate how big
a resistor you need, say start at 5mA and work your way to 30-40 mA.
You can assume the laser diode voltage stays constant with current.
(As a first approx., you can set the diode voltage equal to zero,
with V>12 V.)

George H.

This is it's specs. Should I be looking at the working current?

Material: Plastic and copper
Operating Voltage: 3V DC
Working current: < 40mA
Input power: 150mW
With red dot
Wavelength: 650nm
Output laser power: < 5mW

 

[AK]

On Tuesday, April 30, 2019 at 6:02:59 PM UTC-5, George Herold wrote:

On Tuesday, April 30, 2019 at 4:18:57 PM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 2:32:58 PM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 3:11:37 PM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 1:30:17 PM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 2:02:45 PM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 11:56:27 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 11:21:18 AM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 8:29:22 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.
GH

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

Ahh.. OK those specs look nothing like you first posted.
I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

George H.

Could you give some details on that?

Thanks,
Andy

googles, lm317 current source
http://www.bristolwatch.com/ccs/LM317.htm

GH
Not so good fro small currents but perfect for 10-100mA

+Vcc -------LM 317------10 ohm resistor-----lout
|
.1 uF capacitor

I have a 5 volt power transformer.

Do I get it down to 3 volts first?

Then connect positive to Vcc ?

Does the negative go straight to the laser diode while lout goes to the positive lead of the laser?

Andy

Hmm, well definitely buy more than one laser diode...
'cause I'm guessing you will blow some.
You could put a few 1n4002 in series and use those for a dummy
laser diode.
Read that whole page on LM317 current sources... Make sure
you understand how to choose all the values.
(There is a connection from the output to the adjust pin of lm317)

Maybe read some about how the lm317 works.
10 ohms gives you 120 mA how much current do you want?

George H.

This is becoming quite a complicated project.

I can buy a laser with it's own power supply, but I would prefer building my own.
Well as others have said upstream, the simplest current source is a
voltage source and the right resistor. I think you should start there.
Do you have a DMM voltmeter?
Get a 12V (or other) wall wart, and calculate how big
a resistor you need, say start at 5mA and work your way to 30-40 mA.
You can assume the laser diode voltage stays constant with current.
(As a first approx., you can set the diode voltage equal to zero,
with V>12 V.)

George H.

This is it's specs. Should I be looking at the working current?

Material: Plastic and copper
Operating Voltage: 3V DC
Working current: < 40mA
Input power: 150mW
With red dot
Wavelength: 650nm
Output laser power: < 5mW

Thanks.

I have both DMM and RMS meters.

I decided to order 2 laser diode with a builtin Red Dot Module Diode driver.

The detector and other components of the laser alarm project uses

LDR (Light Dependant Diode)
L.E.D (Light Emitting Diode)
BC547 Transistor (1)
100 ohm or 330 ohm resistor (1)
Buzzer (1)
9v Battery with holder

 

[George Herold]

On Tuesday, April 30, 2019 at 8:49:19 PM UTC-4, AK wrote:

<snip>
said upstream, the simplest current source is a

voltage source and the right resistor. I think you should start there.
Do you have a DMM voltmeter?
Get a 12V (or other) wall wart, and calculate how big
a resistor you need, say start at 5mA and work your way to 30-40 mA.
You can assume the laser diode voltage stays constant with current.
(As a first approx., you can set the diode voltage equal to zero,
with V>12 V.)

George H.

This is it's specs. Should I be looking at the working current?

Material: Plastic and copper
Operating Voltage: 3V DC
Working current: < 40mA
Input power: 150mW
With red dot
Wavelength: 650nm
Output laser power: < 5mW

Thanks.

I have both DMM and RMS meters.

I decided to order 2 laser diode with a builtin Red Dot Module Diode driver.

The detector and other components of the laser alarm project uses

LDR (Light Dependant Diode)
L.E.D (Light Emitting Diode)
BC547 Transistor (1)
100 ohm or 330 ohm resistor (1)
Buzzer (1)
9v Battery with holder

That sounds like it should get you started.
You can use led's to test your circuits..
Cheaper than laser diodes. 30 - 50 mA may
let the 'magic smoke' out of some but lower currents
should be OK.

George H.

 

[AK]

On Tuesday, April 30, 2019 at 8:36:32 PM UTC-5, George Herold wrote:

On Tuesday, April 30, 2019 at 8:49:19 PM UTC-4, AK wrote:

snip
said upstream, the simplest current source is a
voltage source and the right resistor. I think you should start there.
Do you have a DMM voltmeter?
Get a 12V (or other) wall wart, and calculate how big
a resistor you need, say start at 5mA and work your way to 30-40 mA.
You can assume the laser diode voltage stays constant with current.
(As a first approx., you can set the diode voltage equal to zero,
with V>12 V.)

George H.

This is it's specs. Should I be looking at the working current?

Material: Plastic and copper
Operating Voltage: 3V DC
Working current: < 40mA
Input power: 150mW
With red dot
Wavelength: 650nm
Output laser power: < 5mW

Thanks.

I have both DMM and RMS meters.

I decided to order 2 laser diode with a builtin Red Dot Module Diode driver.

The detector and other components of the laser alarm project uses

LDR (Light Dependant Diode)
L.E.D (Light Emitting Diode)
BC547 Transistor (1)
100 ohm or 330 ohm resistor (1)
Buzzer (1)
9v Battery with holder

That sounds like it should get you started.
You can use led's to test your circuits..
Cheaper than laser diodes. 30 - 50 mA may
let the 'magic smoke' out of some but lower currents
should be OK.

George H.

I did some experimenting with the resistance of the photo cell.

Photocell 400mW 350V pack 8K ohm Max Light 1M ohm in. Dark

At about 6 inches from the laser, it's about 165 ohms.

At 18 feet, it is around 160 ohms.
(I turned on a 60 watt light, but it did not appreciably change the resistance.)

In darkness, it is about 24,600 ohms.

 

[AK]

On Saturday, May 4, 2019 at 11:22:52 PM UTC-5, AK wrote:

On Tuesday, April 30, 2019 at 8:36:32 PM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 8:49:19 PM UTC-4, AK wrote:

snip
said upstream, the simplest current source is a
voltage source and the right resistor. I think you should start there.
Do you have a DMM voltmeter?
Get a 12V (or other) wall wart, and calculate how big
a resistor you need, say start at 5mA and work your way to 30-40 mA..
You can assume the laser diode voltage stays constant with current.
(As a first approx., you can set the diode voltage equal to zero,
with V>12 V.)

George H.

This is it's specs. Should I be looking at the working current?

Material: Plastic and copper
Operating Voltage: 3V DC
Working current: < 40mA
Input power: 150mW
With red dot
Wavelength: 650nm
Output laser power: < 5mW

Thanks.

I have both DMM and RMS meters.

I decided to order 2 laser diode with a builtin Red Dot Module Diode driver.

The detector and other components of the laser alarm project uses

LDR (Light Dependant Diode)
L.E.D (Light Emitting Diode)
BC547 Transistor (1)
100 ohm or 330 ohm resistor (1)
Buzzer (1)
9v Battery with holder

That sounds like it should get you started.
You can use led's to test your circuits..
Cheaper than laser diodes. 30 - 50 mA may
let the 'magic smoke' out of some but lower currents
should be OK.

George H.

I did some experimenting with the resistance of the photo cell.

Photocell 400mW 350V pack 8K ohm Max Light 1M ohm in. Dark

At about 6 inches from the laser, it's about 165 ohms.

At 18 feet, it is around 160 ohms.
(I turned on a 60 watt light, but it did not appreciably change the resistance.)

In darkness, it is about 24,600 ohms.

I got my NE 555P chip in. I need some help.

How do I hook up my switch as shown in this diagram?

To turn off the alarm and reset the system, a (single pole double throw) switch disconnects the speaker and sends the LOW signal from the output pin 3 to the trigger pin 2. The system is now deactivated. To reactivate it, flip the switch back to the original position. The alarm will remain off until the next time that the light beam is interrupted.

"https://www.dropbox.com/s/s6s4d93f1wioqpe/Laser_Alarm_Circuit.jpg?dl=0"

"https://www.dropbox.com/s/vbht8ucvjp6qtu2/SinglePoleDoubleThrow.jpg?dl=0"

 

[AK]

On Monday, May 6, 2019 at 4:11:37 PM UTC-5, AK wrote:

On Saturday, May 4, 2019 at 11:22:52 PM UTC-5, AK wrote:
On Tuesday, April 30, 2019 at 8:36:32 PM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 8:49:19 PM UTC-4, AK wrote:

snip
said upstream, the simplest current source is a
voltage source and the right resistor. I think you should start there.
Do you have a DMM voltmeter?
Get a 12V (or other) wall wart, and calculate how big
a resistor you need, say start at 5mA and work your way to 30-40 mA.
You can assume the laser diode voltage stays constant with current.
(As a first approx., you can set the diode voltage equal to zero,
with V>12 V.)

George H.

This is it's specs. Should I be looking at the working current?

Material: Plastic and copper
Operating Voltage: 3V DC
Working current: < 40mA
Input power: 150mW
With red dot
Wavelength: 650nm
Output laser power: < 5mW

Thanks.

I have both DMM and RMS meters.

I decided to order 2 laser diode with a builtin Red Dot Module Diode driver.

The detector and other components of the laser alarm project uses

LDR (Light Dependant Diode)
L.E.D (Light Emitting Diode)
BC547 Transistor (1)
100 ohm or 330 ohm resistor (1)
Buzzer (1)
9v Battery with holder

That sounds like it should get you started.
You can use led's to test your circuits..
Cheaper than laser diodes. 30 - 50 mA may
let the 'magic smoke' out of some but lower currents
should be OK.

George H.

I did some experimenting with the resistance of the photo cell.

Photocell 400mW 350V pack 8K ohm Max Light 1M ohm in. Dark

At about 6 inches from the laser, it's about 165 ohms.

At 18 feet, it is around 160 ohms.
(I turned on a 60 watt light, but it did not appreciably change the resistance.)

In darkness, it is about 24,600 ohms.

I got my NE 555P chip in. I need some help.

How do I hook up my switch as shown in this diagram?

To turn off the alarm and reset the system, a (single pole double throw) switch disconnects the speaker and sends the LOW signal from the output pin 3 to the trigger pin 2. The system is now deactivated. To reactivate it, flip the switch back to the original position. The alarm will remain off until the next time that the light beam is interrupted.

"https://www.dropbox.com/s/s6s4d93f1wioqpe/Laser_Alarm_Circuit.jpg?dl=0"

"https://www.dropbox.com/s/vbht8ucvjp6qtu2/SinglePoleDoubleThrow.jpg?dl=0"

Looks like I need a 8 Pin DIP IC Socket Adaptor Solder Type.

Is this the kind of board I need?

"https://www.dropbox.com/s/2dadbk3dfhkakus/PowerRailBoard.jpg?dl=0 "