From various sources in the internet, the voltage of the red 16x DVD burner led is found to be 3.2V and it's said (in various sources in the 'net) to withstand 250mA current. The laser output power is said to be 250mW. That is the power of the light coming out of the diode. It's not needed for these calculations.
The circuit, like this one, is using two 10 ohm resistors in parallel for the limiting resistor. So the total resistance is 5 ohms, and the resulting wattage is 2x the wattage of the resistors. 5 ohms results in a maximum output current of 250mA.
The two capacitors in the input and in the output can be for example 10 microfarads both. They are there to flatten any voltage spikes coming from the input. The bigger the caps, the flatter the voltages. 10 microfarads should be more than enough.
According to this Davshomepage article, the optimum input voltage is: LD voltage 3.2V + 3V needed by LM317 + 1V reserve = 7.2 V.
However, I'm planning to use this one with a 9V power supply. That means the LM317 will have to dissipate some extra power. Thus, I calculated some power dissipation figures. These are not necessary - if you use the same parts, the circuit will work just the same.
The maximum power dissipation in the whole circuit (including LD) is 9V*0.25A = 2.25 W.
Maximum power dissipation in the driver circuitry is 9V-3.2V*0.25A = 1.45 W.
Maximum power dissipation in the limiting resistor 1.25V * 0.25A = 0.3 W
(the LM317 makes sure there's always 1.25V over the limiting resistor. 0.25A is the maximum current)
Maximum power dissipation in the laser diode is going to be 3.2V * 0.25A = 0.8 W.
(3.2V is the laser diode voltage and 0.25A is the maximum current)
The main thing to look at here is the maximum power dissipation in the limiting resistor. So if I use two 1/4 W resistors, I get about 1/2 W rating for the parallel connection and that's more than 0.3W, so the resistors shouldn't burn out even with maximum output.
I will probably use some salvaged heat sink, at least for the LM317. For the LD (laser diode), the Aixiz module works as a heat sink and should be enough.
Laser diode from a 16x DVD burner drive
LM317 adjustable regulator (preferably in TO-220 package)
2 x 10 ohm 1/4 W resistors
100 ohm potentiometer
2 x capacitors, for example 10uF (microfarads)
A piece of metal as a heat sink for the LM317.
650nm 5.0mW 12x30mm Aixiz module (to house the laser diode)
Stay tuned for part II, where I'll build this circuit.
Davshomepage - Constant current source - A good page that helped me with the power calculations.
Laser Pointer Forums - Daedalus' DIY Homemade laser diode driver - The classic DIY Laser driver.
It can be done - Laser driver - Another page on the laser driver circuit.
LM317 on Wikipedia
National Semiconductor LM317 regulator datasheet
Resistors: color codes, wattages... - A great tutorial page for dummies.