SparkFun Forums

[Oberon]

I'm looking for an economical collimated light source, preferably with a relatively long life, and to work in the 2 - 5m range. While the diameter is not absolutely critical, I'm hoping for something under 6 - 8mm or so.

While a laser fits most of these criteria, they (typically) are not cheap, and seem to be around 5,000 hours MTBF.
I'm looking to use this for alignment monitoring, probably 24x7 over a long period of time.

Would appreciate feedback on if/what technologies/products are out there - expect there should be some, but I haven't found much (other than laser) - though perhaps I haven't been searching right. Thanks in advance for any/all feedback

[Oberon]

I notice a number of views, but no replies .. perhaps I'm asking for something that is too hard ? Perhaps virtually all collimated (i.e. pencil beam) light is in fact laser ?

If so, perhaps some advice regarding laser beams .. I don't fully understand the different colours, but wonder if some are more economical than others ? or are likely to have a longer life ?

What I'm planning to do is to use the beam as an alignment beam, sensing displacement either via direct or indirect method, e.g. photo diode for the former, or optical monitoring for the latter. One way to extend equipment life would be to pulse & read intermittently, e.g. every 25 mins, but (a) would need to be able to remotely turn the system on then off, and (b) ensure that 'warm up time' was relatively small in case of an 'event' requiring immediate monitoring.

Thanks

[haedon]

Something like this
https://www.sparkfun.com/products/10982

[distro inferno]

haedon I'm not sure if that's what Oberon means.

Putting an LED inside a reflective tube that extends out an inch or so from the LED may collimate the beam enough for you.

[guardsmanblue]

Hi Oberon,

I have used the LED laser from a cheap pointer as an alignment device on a set of servos that I needed to align to horizontal. These pointer led lasers are very low power but will excite a photo detector. I connected the terminals of the led coming from the led and collimator lens to a voltage source like a PWM or digital out from an Arduino board. You may have to experiment a little with which lead is the positive and which is the negative. The mean time between failure should be quite long, and considerably cheaper than a true gas laser.

The colors of the laser have to do with the wavelength of light that is emitted. Red lasers are ~600-650 nanometer wavelength and are probably the most common cheap led laser wavelength.

The warm up time for a pointer led laser is very short. You probably would not notice any lag or delay unless using an oscilloscope or other specialized measurement device.

The beam diameter of a pointer led laser is typically small within a distance of 1-2 m. At a range of 5m it should still be smaller than 8mm. The quality of collimation and collimating lens will vary from manufacturer to manufacturer.

Hope this helps.

Guardsmanblue