The title doesn't do this much justice but cant think what else to title it.
My current project to create a comprehensive set of sensors keeps running into the same snag, primarily due to the fact that a single wire is doing 2 way coms and each sensor has to be able to through pass instructions.
The problem that keeps coming up is the fact that there is often a need to be able to listen to a signal while also sending a signal. The attached circuit is the one in use with the exception that C.2 is tied low with a 10K.
C.4 goes to the previous sensor (or main controller) and C.2 goes to the next sensor (is there is one there). there could in theory be a max of 255 sensors in a chain, this will never happen as I do not need that many, nor do I have the energy to make that many.
C.2 has to listen to signals from the next sensor, as well as send them. this is fine for the fact it will spend it time listening while briefly sending "all clear" type signals.
C.4 on the other hand has to send a high or low signal depending on the state of the sensor, but as it currently stands also has to listen for a "all clear" type signal back.
The all clear is normally as simple has pulling the line high. After initialisation and instructions, there is currently only high low signals on the line.
I am thinking that if I connect C.4 and C.5 together and only listen for a high/low on C.5 when C.4 is set as an output and set low (care would need to be used to ensure this is done) but am unsure if this would cause an issue or what protection could or should be used to avoid catastrophe.
there is a part of me that I toying with moving the system to 14M2s and increasing the wire count. it would be the simplest route but have 2 sensors made up on strip board, and sourcing 4 wire connectors and cables. granted they can be repurposed as slightly less intelligent sensors that can be used with me timer or something.
My current project to create a comprehensive set of sensors keeps running into the same snag, primarily due to the fact that a single wire is doing 2 way coms and each sensor has to be able to through pass instructions.
The problem that keeps coming up is the fact that there is often a need to be able to listen to a signal while also sending a signal. The attached circuit is the one in use with the exception that C.2 is tied low with a 10K.
C.4 goes to the previous sensor (or main controller) and C.2 goes to the next sensor (is there is one there). there could in theory be a max of 255 sensors in a chain, this will never happen as I do not need that many, nor do I have the energy to make that many.
C.2 has to listen to signals from the next sensor, as well as send them. this is fine for the fact it will spend it time listening while briefly sending "all clear" type signals.
C.4 on the other hand has to send a high or low signal depending on the state of the sensor, but as it currently stands also has to listen for a "all clear" type signal back.
The all clear is normally as simple has pulling the line high. After initialisation and instructions, there is currently only high low signals on the line.
I am thinking that if I connect C.4 and C.5 together and only listen for a high/low on C.5 when C.4 is set as an output and set low (care would need to be used to ensure this is done) but am unsure if this would cause an issue or what protection could or should be used to avoid catastrophe.
there is a part of me that I toying with moving the system to 14M2s and increasing the wire count. it would be the simplest route but have 2 sensors made up on strip board, and sourcing 4 wire connectors and cables. granted they can be repurposed as slightly less intelligent sensors that can be used with me timer or something.
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