Hi,
I'm trying to build a motion failure alarm to go inside an already complete electro-mechanical system.
Basically there's a piece of metal moving back and forth (linearly at about 70rpm) and I want to sound an alarm if it stops.
I'm working on this idea (see attached). It simply uses an RC network to control some analogue switches.
I imagine the sensor to be a photo-electric one where the output goes high when it senses a presence. This trips SW2 and resets the RC network and starts the cap re-energizing. If it doesn't get this by the time SW1 reaches it's switching voltage, then it trips and sounds the alarm. If it gets a subsequent pulse, it will re-energize and start again.
The supply doesn't have to be 12V, I'm using it currently to fit with a possible sounder, but it'll need to be transformed from mains, so it could be anything really.
Firstly: is this a good system to use? (and will it work)
Secondly, the analogue switches (i'm imagining using a 4066 IC). When do they switch to closed with a rising voltage at the control pin?
Thridly, is this likely to be reliable - ideally, i'd like to leave it running for a few years, non-stop (!!)
Now i haven't finalised R1 and C1, i need to fine tune the timings. I'd like it to start tripping at just less than 60rpm (1hz). Any suggestions, and which kind of cap should i use - i can't get my head around them.
Thanks in advance and I hope you're all well
xephias
I'm trying to build a motion failure alarm to go inside an already complete electro-mechanical system.
Basically there's a piece of metal moving back and forth (linearly at about 70rpm) and I want to sound an alarm if it stops.
I'm working on this idea (see attached). It simply uses an RC network to control some analogue switches.
I imagine the sensor to be a photo-electric one where the output goes high when it senses a presence. This trips SW2 and resets the RC network and starts the cap re-energizing. If it doesn't get this by the time SW1 reaches it's switching voltage, then it trips and sounds the alarm. If it gets a subsequent pulse, it will re-energize and start again.
The supply doesn't have to be 12V, I'm using it currently to fit with a possible sounder, but it'll need to be transformed from mains, so it could be anything really.
Firstly: is this a good system to use? (and will it work)
Secondly, the analogue switches (i'm imagining using a 4066 IC). When do they switch to closed with a rising voltage at the control pin?
Thridly, is this likely to be reliable - ideally, i'd like to leave it running for a few years, non-stop (!!)
Now i haven't finalised R1 and C1, i need to fine tune the timings. I'd like it to start tripping at just less than 60rpm (1hz). Any suggestions, and which kind of cap should i use - i can't get my head around them.
Thanks in advance and I hope you're all well
xephias
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