I am attempting to build a PIC16F676 based voltmeter using 3 multiplexed common-anode seven segment displays. Is it possible to add a light activated dimmer to control brightness of the displays through the PIC or control the current externally against the displays them selves? It would result in a bright display in bright conditions and dimmer in dark conditions to not be blindingly bright or distracting. Most standard seven segment displays are not usually that bright but this is a large display using bright leds.
Edit: I am adding the schematic that I'm working off of. Guess I should have added in the beginning. Sorry folks.
In the display, each segment contains 5x leds in parallel. As a result, the BC557's will need to be changed to something larger as 5x parallel leds may draw >100ma. The problem of the leds is that I'm using 01005 SMD leds in a small form factor but I am only finding them in stoopid bright instead of standard bright. :( When I thought of posing this question, I had difficulty figuring how to title it and I'm trying not to draw the question in that direction.