Hi, i am currently working on an projects and it consist of a DPDT(NC) mechanical relay, 7404 inverter and C8051F226 microproccessor. This is how it works, a 5VDC was connected to the "Common" of the mechanical relay and pin 1 which is the contact that normally closed with the common pin is connected to the inverter.
In this case, if i didnt toggle the relay, it will send a logic 1 to the inverter to invert into logic 0 and send it to the MP. I was able to detect logic 1 when the relay is in an ON state and subsequent a logic 0 when i toggle it back to OFF state. However, i encountered a problem.
The MP was not able to detect any logic when the relay is from an OFF to an ON state. I happened to discover that when i use an mixed signal oscilloscope probe to merely came in contact with the interver pin that is connect relay pin 1, the MP suddenly able to detect the logic. But that also mean that i have to constantly use the probe to touch the inverter to make it works. Any kind soul or pros out there can help me with it? Thanks inadvance to those who help.
In this case, if i didnt toggle the relay, it will send a logic 1 to the inverter to invert into logic 0 and send it to the MP. I was able to detect logic 1 when the relay is in an ON state and subsequent a logic 0 when i toggle it back to OFF state. However, i encountered a problem.
The MP was not able to detect any logic when the relay is from an OFF to an ON state. I happened to discover that when i use an mixed signal oscilloscope probe to merely came in contact with the interver pin that is connect relay pin 1, the MP suddenly able to detect the logic. But that also mean that i have to constantly use the probe to touch the inverter to make it works. Any kind soul or pros out there can help me with it? Thanks inadvance to those who help.