astronomerroyal
New Member
Hello,
Does anyone know of a phototransistor design with a surface area approx. that of a dime or nickel or even larger.
Why? I wish to detect a laser beam from some distance i.e. a laser tripwire. Currently I'm using an array of three of those standard 5mm(?) phototransistors, wired in parallel. The laser still has to fall exactly on one of them, but having three helps somewhat. In this case the problem is that the 'packing efficiency' is not very high. In the field it's very difficult to get things lined up so precisely. I considered putting slightly opaque plastic over the phototransistors to diffuse the incoming light, so that it fell more evenly. in this case the problem is light loss.
I took a look on mouser and digikey for large phototransistors - utter failure. I don't really know what to search for.
I actually want to find two types; sensitive to 650nm and 980nm. Finally, I considered CdS cells, but they're too slow.
Any help greatly appreciated.
Does anyone know of a phototransistor design with a surface area approx. that of a dime or nickel or even larger.
Why? I wish to detect a laser beam from some distance i.e. a laser tripwire. Currently I'm using an array of three of those standard 5mm(?) phototransistors, wired in parallel. The laser still has to fall exactly on one of them, but having three helps somewhat. In this case the problem is that the 'packing efficiency' is not very high. In the field it's very difficult to get things lined up so precisely. I considered putting slightly opaque plastic over the phototransistors to diffuse the incoming light, so that it fell more evenly. in this case the problem is light loss.
I took a look on mouser and digikey for large phototransistors - utter failure. I don't really know what to search for.
I actually want to find two types; sensitive to 650nm and 980nm. Finally, I considered CdS cells, but they're too slow.
Any help greatly appreciated.