My class project is to build a battery operated light detector circuit using a photodiode and a LED light bar to register the light intensity. The photo diode output is connected to a single-supply 5 volt Op Amp (battery operated). The Op Amp feeds a national semi LM3914 IC light bar driver, which powers the lightbars.
When the photodiode detects light, the light bars illuminate according to the light intensity; and works fine. Unfortunetly, I need the reverse; I need the light bars to illuminate when the photodiode is in the dark and extingush when the photodiode detects light. What can I put between the Op Amp out put and the lightbar driver to inverse the driver signal? The OP Amp is battery operated and is powered by +5v, so inverting the Op amp connection will not work.
The LM3914 LED lightbar driver input single is 0 to 2.5vdc for full off or full on respectfully.
Any help or discussion would be a big help.
Thanks all.
When the photodiode detects light, the light bars illuminate according to the light intensity; and works fine. Unfortunetly, I need the reverse; I need the light bars to illuminate when the photodiode is in the dark and extingush when the photodiode detects light. What can I put between the Op Amp out put and the lightbar driver to inverse the driver signal? The OP Amp is battery operated and is powered by +5v, so inverting the Op amp connection will not work.
The LM3914 LED lightbar driver input single is 0 to 2.5vdc for full off or full on respectfully.
Any help or discussion would be a big help.
Thanks all.