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By Userxyz
#191955
Hi,

I just have received the SparkFun IR sensor board quoted above. But it is not suitable for the concept I have on a 'digital ambient light filter'.

I suggest a decimal counter with 10 decoded outputs, like the CMOS 4017. On its zero stage, the IR diode is off. On the further stages, it will be on. The IR transistor, however, is adressable from 0 to 9.

Ambient light may be assumed if the transistor is addressed also during counter stage # 0. In this case, the counter had to be stopped, cutting the output (e.g. to a LED) off. Output condition if reflexion detected: Diode AND transistor ON during stages 1 to 9 (or better less, e.g. from 1 to 3, with #4 for counter reset).

For this application, the diode as well as the transistor could be kept connected to common Vdd, but the Vss terminals of the diode and the transistor had to be separated. This as my proposal to the SparkFun engineers: One more output on the break-out, jumper to connect the diode and transistor Vss outputs if requested.

Kind regards,

Bertold Langer