Hi,
To cut to the chase:
I need to control the brightness of a Red Laser Diode from a Microcontroller.
What is the best frequency and duty cycle range to drive a Red Laser Diode from a Microcontroller?
Has anyone got any circuit diagrams for PWM driving? Can I get away with PWM from Micro and a 47uf Cap?
Can you PWM drive a red laser diode at 6v+ with a lower duty cycle (normally run off 3v)? (ie. using two CR2032's or two CR2016's)
Has anyone run a laser diode of a Joule Thief?
(I have some cheap $2 Red laser pointers I can smoke test before I use the $40 Laser sight.)
Background Info:
I've been playing with ATMEL ATTINY13 programmable microcontrollers and I had a ?great? idea last night.
I play Airsoft and I use Red Dot Sights on my guns that work by reflecting a low power laser off a specially coated lens.
They usually have 10-12 "brightness" settings for various ambient lighting conditions.
The big problem is that they are REALLY easy to
a) leave the power on
b) knock the power on
This results in a lot of dead CR2032 and LR44 batteries which are also difficult/annoying to change :'(
High end Commercial models aimed at military tend to have nice features like 50,000 hours battery life, run off AA's and auto shut-off.
Obviously they have high end optics and components to achieve that kind of efficiently, this comes with a nice price tag ($300us+)
I have three main idea's to replicate these features to upgrade an existing cheap $30US Red dot sight:
a) Add a micro controller to implement PWM brightness control and Auto shut off ...
(Micro uses <0.1uAH in power down mode, thats 200years on a CR2032 batt.)
b) Use Photo detector (X to micro) to auto adjust the brightness level.
c1) Look at using a Joule Thief to run the whole thing off low voltage source, ie. A single AA or AAA battery.
or
c2) Use two CR2032's or CR2016's and run the thing off 5v with Voltage Regulator.
Final note: I want to try and keep the part count as low as possible.
Ie.
Batteries.
2x push buttons
2x pull up resistors
1x ATTINY micro (Using DIP8 but may go SMD )
1x Transistor ? SMD ? (for PWM the LD)
1x 47uf Cap (Voltage smoothing)
1x Laser Diode
Joule thief would obviously require more parts.....
To cut to the chase:
I need to control the brightness of a Red Laser Diode from a Microcontroller.
What is the best frequency and duty cycle range to drive a Red Laser Diode from a Microcontroller?
Has anyone got any circuit diagrams for PWM driving? Can I get away with PWM from Micro and a 47uf Cap?
Can you PWM drive a red laser diode at 6v+ with a lower duty cycle (normally run off 3v)? (ie. using two CR2032's or two CR2016's)
Has anyone run a laser diode of a Joule Thief?
(I have some cheap $2 Red laser pointers I can smoke test before I use the $40 Laser sight.)
Background Info:
I've been playing with ATMEL ATTINY13 programmable microcontrollers and I had a ?great? idea last night.
I play Airsoft and I use Red Dot Sights on my guns that work by reflecting a low power laser off a specially coated lens.
They usually have 10-12 "brightness" settings for various ambient lighting conditions.
The big problem is that they are REALLY easy to
a) leave the power on
b) knock the power on
This results in a lot of dead CR2032 and LR44 batteries which are also difficult/annoying to change :'(
High end Commercial models aimed at military tend to have nice features like 50,000 hours battery life, run off AA's and auto shut-off.
Obviously they have high end optics and components to achieve that kind of efficiently, this comes with a nice price tag ($300us+)
I have three main idea's to replicate these features to upgrade an existing cheap $30US Red dot sight:
a) Add a micro controller to implement PWM brightness control and Auto shut off ...
(Micro uses <0.1uAH in power down mode, thats 200years on a CR2032 batt.)
b) Use Photo detector (X to micro) to auto adjust the brightness level.
c1) Look at using a Joule Thief to run the whole thing off low voltage source, ie. A single AA or AAA battery.
or
c2) Use two CR2032's or CR2016's and run the thing off 5v with Voltage Regulator.
Final note: I want to try and keep the part count as low as possible.
Ie.
Batteries.
2x push buttons
2x pull up resistors
1x ATTINY micro (Using DIP8 but may go SMD )
1x Transistor ? SMD ? (for PWM the LD)
1x 47uf Cap (Voltage smoothing)
1x Laser Diode
Joule thief would obviously require more parts.....