This is a simple and cheap homemade laser driver.
The LM317 is capable of up to 1.5A,
which makes it possible to use it for >1000mW laser diodes.
Build your own homemade laser driver
- LM317 Voltage Regulator (rs-components)
- 1N4001 Diode (Reverse Voltage Protection)
- 10µF Capacitor
- Resistors (Value depending on diode current)
- Potentiometer (only necessary if you want to change the diode current)
All parts together cost me around 2€. (~2.5$)
The Resistor is to be calculated as follows:
Resistance = 1.25V / max. Current to Diode
The 1.25V is the Reference Voltage of the LM317.
maximum diode current is 250mA:
1.25V/0.25A = 5 Ohm
The Variable Resistor can be used to control the current to the diode.
The Current can be calculated with this formula:
I = 1.25V / Resistor + <Variable Resistor>
Insert the momentary Resistance of the potentiometer here.