PV Cell application with an iverter op-amp.

[Ari Kelenson]

Hello guys,

I am trying to connect a PV cell from a calculator to a TL074CN op-amp.
My goal is to emit light on the PV cell, and thus get some small value of current in the input pin and then amplify it so that I can get a range of voltages values 0-5V in the Vout pin by changing the value of RF.

I dont really have experience with PV cells nor op-amps, but after some reading I tried to implement the "Virtual ground" op-amp(See attached schematics) :

so to the Vin pin I connected the + probe of the PV cell

my questions are:

1) is my schematics o.k in order to obtain a range of 0-5V in the Vout pin?

2) what kind of PV cell is good enough to botain this goal?

any comments/advices will be greatly appreciated.

Thank you!

 

[(*steve*)]

A LED will do what you want, a PV cell, almost certainly not.

 

[Ari Kelenson]

Thank you Steve,

the application I want is to be used outdoors and obtain position of a qaudcopter based on the angle the light hits the PV cell is there no other way to obtain it using a PV cell?

 

[(*steve*)]

Perhaps you can describe the problem in a way that a person not familiar with it can understand (i.e. Dumb it down for me )

 

[davenn]

Thank you Steve,

the application I want is to be used outdoors and obtain position of a qaudrotor based on the angle the light hits the PV cell is there no other way to obtain it using a PV cell?

I seriously doubt that you will get a wide variation of current generated by the PV cell for anything but the widest of angle changes ...
that is its not likely to give you the sort of angle change resolution you are expecting/hoping for

Dave

 

[Ari Kelenson]

Perhaps you can describe the problem in a way that a person not familiar with it can understand (i.e. Dumb it down for me )

Hi again Steve,
OK, so the main idea goes as follows:
Usually Quadcopters ( unmanned flying vehicle with 4 rotors) fly around a closed room with the help of cameras and image processing.
I want to implement a pair of photovoltaics glued together with a 90 degree angle between them. This set of PV cells is to be placed on top of the quadcopter.
Now, the total induced current coming form both PV cells are directly proportional to the total angle of incidence on the surface of the cells.
Thus, the output of the Op-amp that I attached previously, for both PV cells, will depend on the induced currents from the cells.
Finally, feeding the output to a micro-controller, I can then program it to use some math and determine the angel of incidence and eventually the coordinates of the quadcopter in a 2D plane.
The height of the quadcopter would be determined using another sensor, but for now that's not my goal.
So, that's the general scope of the project I'm working on.
Any ideas or tips is appreciated.
Thanks again.

 

[(*steve*)]

The current is going to be roughly proportional to the incident light.

If you have a single light source, the current will be proportional to the cosine of the angle and inversely proportional to the square of the distance.

Ignoring that PV cells are not particularly suited to this, there are still a number of problems. A quadcopter can move and rotate in any axis. I can't see how a single light source will allow you to get fix on a position.

At best it will allow you to orient yourself so that you know you're pointing in a particular direction relative to the light source.

TO do this you'd probably need a differential amplifier to determine which sensor is seeing the most light.

 

[BobK]

And do paint the room matte black so that it is not confused by reflected light.

Bob