I want to create a door lock system that uses the wall outlet. One thing I also want to do, if the power ever turns off, is somehow get the circuit to switch to using a battery instead, so the door can still be unlocked. How would I go about doing this? I spent some time looking for the solution, but couldn't think of or find one.

 

hi bl,
Welcome to AAC.
What voltage is the door lock system.??
E

 

hi bl,
Welcome to AAC.
What voltage is the door lock system.??
E

I haven't planned it out much at all yet. Just enough to power a receiver and servo or dc motor.

 

hi,
A low voltage DC system would be one option, a simple pair of diodes could be used.
E

 

One way to do this is the have the line power a little higher in voltage than the battery. Then you put a diode between each and device. The higher voltage will override the lower one, so when the AC power is on, the battery is not used, when the AC power is off, the battery is used.

Bob

 

hi,
A low voltage DC system would be one option, a simple pair of diodes could be used.
E

I'll definitely look into that. Thank you for such prompt replies. I was honedtly not expecting them to be so fast. How would I configure/wire up the diodes to get that to work?

 

One way to do this is the have the line power a little higher in voltage than the battery. Then you put a diode between each and device. The higher voltage will override the lower one, so when the AC power is on, the battery is not used, when the AC power is off, the battery is used.

Bob

I'm having trouble visualizing the connections. The battery is wired up in series with the wall outlet, but the wall outlet is above the battery, or closer to the load. What would be the configuration of the diodes?

 

hi,
This would be an option.
When you decide on the lock current , choose Wart and diodes to suit.
E

 

hi,
This would be an option.
When you decide on the lock current , choose Wart and diodes to suit.
E
View attachment 185520

Thank you so much for the schematic. I might just use my phone's charger instead of a wall outlet, to get DC indtead of havjng to include an ADC into the configuration. I'll look into everything you've provided.

 

hi,
I would do a search for a suitable low voltage locking unit, then we can finalise the volts/current etc.
Let us now when you have found a lock unit.
E

 

hi,
I would do a search for a suitable low voltage locking unit, then we can finalise the volts/current etc.
Let us now when you have found a lock unit.
E

I want to try and make the locking unit on my own. I plan to buy an ESP 7/8" Thumb Turn Lock (https://www.easykeys.com/ProductSpe...2TsS9aEWiONQUBgf5c6RW41irJEuNEPEaAiO3EALw_wcB) and a 9g micro servo motor using 4.8V (https://www.robotshop.com/en/9g-micro-servo-motor-4-8v.html). Going to try and attach the motor onto the lock, so that it'll turn it when activated.