sorry but I cannot open the attachment with the circuit diagram, I cannot open docx-files. Could you please attach a common file format, you attached a doc-file in another posting.
sorry but this attachment does not work either, I tried to open it with Word but it does not show up correctly.
Anyhow, you should check the voltage on the digital input with the LDR under light and in darkness (covered). The voltage for a high input should be above 2.8V and the voltage for a low input shcould be less than 0.8V.
At first glance there is nothing wrong with your setup.
What happens when you short (connect) the two output terminals? Since you (hopefully) use an open collector configuration this will just simulate an activated output transistor.
Hi, Thanks a lot for your effort, its true there is nothing wrong with the circuit, it's just how the connection between the transistor output to the digital input.
