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Last edited by OneAndOnlyOdin on 12 Jan 2022, 13:25, edited 1 time in total.
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Re: Electromagnet WiFi Release - Arduino like device
just a quick safety warning
make sure the key WILL detach from the electromagnet when the power is off. Electromagnets can have "remanent" magnetism - that is, the core of the magnet retains weak magnetism when not powered, so use a weight of some kind to overcome this, to guarantee the key falls.
make sure the key WILL detach from the electromagnet when the power is off. Electromagnets can have "remanent" magnetism - that is, the core of the magnet retains weak magnetism when not powered, so use a weight of some kind to overcome this, to guarantee the key falls.
be a switch, double the fun
Re: Electromagnet WiFi Release - Arduino like device
Hmm..
That may have a failure mode where a client connects but never sends data. Now the loop() function won't move on and so won't test the tickOccured.
Also not sure how accurate your timing is; multiple ticks could occur in the "read from client" part, but it'll only count as 1 second.
Do you want a persistent connection, or should there be a client.stop() call to force close the connection?
I would recommend putting a secondary backup of having the power supply on a time switch, so if the ESP crashes internally with the relay locked then eventually you'll get to "powerfail" state... even if it's an hour later!
And also don't put the electromagnet above your head; you don't want it falling on you when the release happens!
Code: Select all
while(!client.available()){
delay(1);
}
Also not sure how accurate your timing is; multiple ticks could occur in the "read from client" part, but it'll only count as 1 second.
Do you want a persistent connection, or should there be a client.stop() call to force close the connection?
I would recommend putting a secondary backup of having the power supply on a time switch, so if the ESP crashes internally with the relay locked then eventually you'll get to "powerfail" state... even if it's an hour later!
And also don't put the electromagnet above your head; you don't want it falling on you when the release happens!
Re: Electromagnet WiFi Release - Arduino like device
excellent advice from sweh!sweh wrote:Hmm..And also don't put the electromagnet above your head; you don't want it falling on you when the release happens!Code: Select all
while(!client.available()){ delay(1); }
and why don't you put the electromagnet above you ?
because if your arms are above your head for a surprisingly short time (minutes) they will go numb and the muscles will simply "flop" when the release occurs
be a switch, double the fun
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Last edited by OneAndOnlyOdin on 12 Jan 2022, 13:26, edited 1 time in total.
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Re: Electromagnet WiFi Release - Arduino like device
Just as a suggestion, I would like to mention that if you can control a magnet to release a key, you can also control a magnet to release a limb
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Last edited by OneAndOnlyOdin on 12 Jan 2022, 13:27, edited 1 time in total.
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Re: Electromagnet WiFi Release - Arduino like device
The 12V electromagnet in my picture uses only between 100 and 150 mA, which practically any relay will be able to handle. That said, I use a MOSFET, not a relay to switch the magnet.OneAndOnlyOdin wrote:@onwrikbaar I agree that would be an interesting use case however I would suggest to use a different relais* . I assume the one used on the picture over at github might not be strong enough and could cause the ESP to burn out if the blind current gets to high. This might in turn result in you/someone to be locked up forever. I strongly suggest you talk to someone who understands electricity better than me to avoid that.
* The thing separating the circuit of the ESP from the circuit of the electro magnet to prevent the blind current of the electromagnet from destroying the ESP.
And of course there's always a backup timer to eventually cut the power to the magnet in case of hardware or software failure.