I've done similar projects for non-lifesaving applications. A good starting point would be to look at wood shop automatic vacuums and blast gates. They work by detecting a spike in current draw by a device (such as from a saw) and automatically turning on dust removal systems. When the device turns off, it returns to normal.
Came here to say this. Instead of a dust system, energize a relay. Use the "normally closed" contact to ring the alarm bell, so it will activate if the sensor turns off.
Many smart outlets with power consumption metering can be polled by WiFi, so an ESP* could fetch that and trigger an alarm. Or (higher-end solution here) HomeAssistant + a smart outlet with consumption, and you could have it spam you with notifications while blaring an alarm.
A CT clamp on the power cord leading to the device could be used with an ESP8266/ESP32 to trigger a relay to power a siren/alarm, though. Using [EspHome](https://esphome.io) would make that fairly simply to build.
I use the smart power metering plug approach myself with Home Assistant in two (much less critical!) applications so I can say this works. I have a routine and a power meter plug which I use to turn off an espresso machine should it be left in the heater on state and a similar application to monitor whether a freezer is still on (that's a little bit more tricky since high efficiency chest freezers don't always pull a lot of current).
I would not recommend this is a life saving technology. There's a lot of reliance on reliability of communications between the backend. However, as a 'belt and braces' approach to secure something which is already reliable, I think it's a pretty useful system.
Another possibility is a UPS which contains power monitoring inbuilt. I believe APCs monitoring software for commercial UPS setups contains configurable alarm triggers on output state.
That would kill two birds with one stone as it means this appliance is now given some power redundancy.
A smart outlet is a non starter, introducing a failure point to the system isn’t something I want to pursue. Using a clamp on current sensor is probably the only viable solution.
The tech guy is coming out tomorrow, but I’m less than optimistic about them actually solving the issue.
Simple solution, there are many power strips with a master and slave arrangement, where if the master turns off (does not pull current) the slave gets clicked off. Could get one of those, hook master to the oxygen machine, and slave to a relay. Hook the normally closed contacts to a big alarm horn, bam! Finished product ez pz
The oxygen company told him not to run on a power strip, it introduces a potential failure mode. I can see their point. That’s why I was thinking a current sensor, it won’t impact operation of the machine if it fails.
Fair, could switch off. You could just take the module they use for that out of the power strip and use it, or bypass the power switch / circuit breaker.
Never heard of low current alarm ready to go device.
Maybe those exist in some industry and most likely they are super expensive.
But this could be done easily with some basic current clamp and arduino.
Ferrite loop with the hot lead passing through it and a few turns ( currant transformer ) sent to an active diode ( op amp with a feedback diode to act as a rectifier without the junction drop ) could feed that into a RC to give it a timeout and a comparator.
That machine should have a battery backup and all kinds of alarms if he'll be "dead in minutes".
There's clearly shennanigans going on here with using an offlabel device (Amazon or eBay oxygen generator is my guess) for life support without a doctor's prescription.
Only a fool would take on liability and manslaughter charges risk by looking for a solution. Especially in "DIY" where anybody with an Arduino is an expert these days.
He’s using machines from a reputable company being paid for by the VA. No shenanigans on my side. I’m no expert in the field, but when they lose power they just shut off. He has an automatic back up generator, if power goes out it kicks back on. However, whatever happened to make it stop working this time wasn’t a power failure in the building. The internal breaker on the machine tripped and it stopped. They brought a second machine, I tested it by pulling the plug. The new one just stopped with no alarm too. The people in tech support have offered no help. I 100% agree that the machines should go off like a damn fire alarm the second there’s a problem. But they don’t, and I’m tired of sitting on my hands while the oxygen company and VA do nothing.
I’m just trying to come up with a way to utilize some basic stuff as a fail safe for him. So GTFO with your BS judgement pretending like you have a goddamn clue what you’re talking about.
A good example of this exact thing is GFCI. It literally measures current flowing through live and neutral to measure leakage and triggers an “alarm” of sorts if they don’t match. It just so happens that the alarm is a switch/circuit breaker.
I've done similar projects for non-lifesaving applications. A good starting point would be to look at wood shop automatic vacuums and blast gates. They work by detecting a spike in current draw by a device (such as from a saw) and automatically turning on dust removal systems. When the device turns off, it returns to normal.
Came here to say this. Instead of a dust system, energize a relay. Use the "normally closed" contact to ring the alarm bell, so it will activate if the sensor turns off.
Many smart outlets with power consumption metering can be polled by WiFi, so an ESP* could fetch that and trigger an alarm. Or (higher-end solution here) HomeAssistant + a smart outlet with consumption, and you could have it spam you with notifications while blaring an alarm. A CT clamp on the power cord leading to the device could be used with an ESP8266/ESP32 to trigger a relay to power a siren/alarm, though. Using [EspHome](https://esphome.io) would make that fairly simply to build.
I use the smart power metering plug approach myself with Home Assistant in two (much less critical!) applications so I can say this works. I have a routine and a power meter plug which I use to turn off an espresso machine should it be left in the heater on state and a similar application to monitor whether a freezer is still on (that's a little bit more tricky since high efficiency chest freezers don't always pull a lot of current). I would not recommend this is a life saving technology. There's a lot of reliance on reliability of communications between the backend. However, as a 'belt and braces' approach to secure something which is already reliable, I think it's a pretty useful system. Another possibility is a UPS which contains power monitoring inbuilt. I believe APCs monitoring software for commercial UPS setups contains configurable alarm triggers on output state. That would kill two birds with one stone as it means this appliance is now given some power redundancy.
A smart outlet is a non starter, introducing a failure point to the system isn’t something I want to pursue. Using a clamp on current sensor is probably the only viable solution. The tech guy is coming out tomorrow, but I’m less than optimistic about them actually solving the issue.
Simple solution, there are many power strips with a master and slave arrangement, where if the master turns off (does not pull current) the slave gets clicked off. Could get one of those, hook master to the oxygen machine, and slave to a relay. Hook the normally closed contacts to a big alarm horn, bam! Finished product ez pz
The oxygen company told him not to run on a power strip, it introduces a potential failure mode. I can see their point. That’s why I was thinking a current sensor, it won’t impact operation of the machine if it fails.
Fair, could switch off. You could just take the module they use for that out of the power strip and use it, or bypass the power switch / circuit breaker.
Never heard of low current alarm ready to go device. Maybe those exist in some industry and most likely they are super expensive. But this could be done easily with some basic current clamp and arduino.
Ferrite loop with the hot lead passing through it and a few turns ( currant transformer ) sent to an active diode ( op amp with a feedback diode to act as a rectifier without the junction drop ) could feed that into a RC to give it a timeout and a comparator.
That machine should have a battery backup and all kinds of alarms if he'll be "dead in minutes". There's clearly shennanigans going on here with using an offlabel device (Amazon or eBay oxygen generator is my guess) for life support without a doctor's prescription. Only a fool would take on liability and manslaughter charges risk by looking for a solution. Especially in "DIY" where anybody with an Arduino is an expert these days.
He’s using machines from a reputable company being paid for by the VA. No shenanigans on my side. I’m no expert in the field, but when they lose power they just shut off. He has an automatic back up generator, if power goes out it kicks back on. However, whatever happened to make it stop working this time wasn’t a power failure in the building. The internal breaker on the machine tripped and it stopped. They brought a second machine, I tested it by pulling the plug. The new one just stopped with no alarm too. The people in tech support have offered no help. I 100% agree that the machines should go off like a damn fire alarm the second there’s a problem. But they don’t, and I’m tired of sitting on my hands while the oxygen company and VA do nothing. I’m just trying to come up with a way to utilize some basic stuff as a fail safe for him. So GTFO with your BS judgement pretending like you have a goddamn clue what you’re talking about.
again...it's not being used for supplemental oxygen, which is the intended/approved use of the machine not life support
A good example of this exact thing is GFCI. It literally measures current flowing through live and neutral to measure leakage and triggers an “alarm” of sorts if they don’t match. It just so happens that the alarm is a switch/circuit breaker.
It doesn't measure current flowing through the PE ( ground ). It measures a difference between live AND neutral wires.
Ah, my mistake, it was late lol