Electronic – Using a solar panel for laser light detection

laserphotodiodesolar cell

I've been planning on putting together a laser tag system and one of the big concerns I have is that photoresistors/phototransistors have relatively small surface areas w/r/t a human body. On the other hand, solar panels have lots of surface area and the scrap ones are cheap enough to slap on a vest.

I've been doing some digging and I found this video where some students at a university manage to detect a modulated laser with a solar panel. They don't mention much in the way of parameters however. I don't know if it was a consumer grade laser pointer or if it was a commercial grade laser, for example. Neither do I know if the panel was extremely sensitive or if it was just any cheap panel they had around.

So I've come with questions. What are the basics of working with solar panels in terms of output characteristics? What equations do I need to know?

Second, does anyone have experience with either lasers or panels (preferably both) who might be able to point out any obvious pitfalls I've overlooked.

Best Answer

In general, you can detect laser with solar panels. There is intensive research on possibilities of employing lasers in wireless power transmission (Laser Power Beaming). Laser Power Beaming have already been used in order to provide energy for remotely controlled machines (example).

It is my belief that we are 20-30 years from the point when Laser Power Beaming from orbital based photovoltaic power collectors (satellites) will be possible (remember SimCity?).

That said, it seems like you are not that into wireless power transmission. I guess you want to use laser as means of transmitting some information to an electrical circuits which get attached to humans clothes, right?

Well, I've seen (and used) few military combat simulation systems which employ lasers in order to allow soldiers to shoot at each other (without killing each other). Even those systems which are vehicle mounted did not use photovoltaic cells in order to detect laser radiation.

We could provide you with a bunch of information about photovoltaics and lasers, but I believe that your initial direction is incorrect. You can use several photodiodes scattered over the body in order to increase the coverage of your system - it will be cheaper, simpler and much more durable approach.

If sensitivity is your concern, you might want to check out for photomultiplier. These devices have very high sensitivity, but are more complex and more expensive than photodiodes. They are also much more prone to mechanical damage.