Electronic compound eye

I have been experimenting with a current to voltage converter to use with a device like the above to convert the current output of the photo resistors to a voltage level that the arduino analog pins can read.

A BC558 with a 100R resistor on its collector to GND seems about right and produces a wide variation in voltage for a fairly narrow range of base output currents.

What if I wanted to pulse the IR LEDs, like TV remotes, so that a device like this would work in daylight.

What is the best way to filter out the DC component of the IR phototransistor output from sunlight?

Is this relatively easy to do in the same way as the TV IR receivers? Or is it impractical?

Normally running a signal thru a cap takes out the DC component of a signal.

Normally you would use a tuned amplifier, that is an active band pass filter with gain centered on your modulation frequency.
You can not work under all external daylight conditions as the receiver can become saturated and no ammount of extra modulated light will get any more signal out of it.

Interesting.....

With a standard IR receiver from a TV, the only 'filter' that I have found so far that diminishes the signal from a remote it 5 layers of news paper. And you have to hold the paper right over the IR LED to prevent reflected signals.

I tried several glass microscope slides and that did not stop the signal. Although it may be due to reflections from the glass surface since you cannot wrap microscope slides over the end of the remote.

Stick - wrong end of - you hold.
Filter:-

This circuit works brilliantly. I added a BC559 to invert the signal from a drop in voltage to a rise in voltage with increasing IR intensity.

What if you were to replace either the 10k or the 1M with an LDR so that the 'eye' has some ability to adjust its sensitivity to different ambient light levels? Are there IR sensitive LDRs?

What if you were to replace either the 10k or the 1M with an LDR so that the 'eye' has some ability to adjust its sensitivity to different ambient light levels?

I don't think that would work. It would not adjust the sensitivity of the sensor, simply change the output. You might tend to think that is the same thing but it isn't.
The IR sensor can become saturated, that is no amount of extra light will produce any extra signal, that is the limiting factor with interfering light. The amplification applied to the sensor's output simply sets the voltage you get when this saturation occurs it will not affect the point at which the sensor becomes saturated.

Grumpy_Mike:

What if you were to replace either the 10k or the 1M with an LDR so that the 'eye' has some ability to adjust its sensitivity to different ambient light levels?

I don't think that would work. It would not adjust the sensitivity of the sensor, simply change the output. You might tend to think that is the same thing but it isn't.
The IR sensor can become saturated, that is no amount of extra light will produce any extra signal, that is the limiting factor with interfering light. The amplification applied to the sensor's output simply sets the voltage you get when this saturation occurs it will not affect the point at which the sensor becomes saturated.

What about if you were to put some sort IR translucent filter over the top of the phototransistors for outdoor usage?

With respect to the RC differentiator on this page: http://www.electronics-tutorials.ws/filter/filter_3.html, what is considered as high, low and medium frequency?

boylesg:
With respect to the RC differentiator on this page: http://www.electronics-tutorials.ws/filter/filter_3.html, what is considered as high, low and medium frequency?

It can be absoloutly anything. It is just a low pass lets everything through up to a specific frequency and a huge pass lets everything through after a certain frequency. A band pass as the name says let's only a band off frequencies through.

With regard to the optical filter to get an improvement you have to have a narrow band width. These are normall implemented as interference filters and can be quite expensive. I have one for astronomy that just cuts out yellow light and let's all other colours through.