DIY Smart(ish) door closer for about 30USD - battery operated, USB rechargeable, RF controlled

[Mahko_Mahko]

DIY(ish) Smart(ish) door closer for about 30USD - battery operated, USB rechargeable, RF controlled

Sick of your wifi leaking out of the open doors? Hate closing doors but don’t mind opening them? Then this is the perfect gadget for you!

Video of it operating:

Door closer

Functionality summary:

• Spring loaded door is released by battery operated mechanism that is controlled via RF/433mhz.
• No power cables and recharge via powerbank etc

My main use case:

• Close some doors when heater/air con kicks in.
• Also close door if sunlight is shining on my guitars.

Door closing mechanism

Cabinet lock

Replace motor controller and power supply

The 9V battery USB recharging port is (relatively) accesible post assembly

How the internal mechanisms look when you crack open the cabinent lock.

Materials List:

• Latching mechanism and main enclosure (10USD): https://www.aliexpress.com/item/32995736248.html?spm=a2g0s.9042311.0.0.27424c4dEfC96v
• Door closing mechanism (10 USD) https://www.aliexpress.com/item/33014229079.html?spm=a2g0o.productlist.0.0.75324e32270RQD&algo_pvid=045c6b3b-4dd7-45a8-8407-983fe1ebe543&algo_expid=045c6b3b-4dd7-45a8-8407-983fe1ebe543-4&btsid=0ab6f82215878673063833513e377e&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_
• RF 433mhz motor controller (4USD): https://www.aliexpress.com/item/32982568818.html?spm=a2g0s.9042311.0.0.27424c4dD6pZVR
• 9V usb rechargeable battery (4USD): https://www.aliexpress.com/item/4000121654682.html?spm=a2g0s.9042311.0.0.27424c4d8lEfhn
• 9v connector (0.25USD) https://www.aliexpress.com/item/32828564174.html?spm=a2g0s.9042311.0.0.27424c4d8lEfhn
• If you don’t have a Sonoff RF bridge or Broadlink RM pro, you’ll need that for RF 433mhz control. I think they’re great and you really should get one anyway.

Outline of approach:

• Replace RFID motor control board with RF control board
• Replace 2 x AA power supply with 9V USB rechargeable power supply.

Con’s:

• Door may not fully latch close (but this doesn’t necessarily really matter)
• No open sesame, only close sesame.
• A fair bit of hardware mods and plastic cutting etc.
• I 3d printed a holder for the clasp thingo that attaches to the door.

Reliability:

• Will report back on general reliability
• I’m a little suspicious of 9V battery capacity and RF control power usage, but if they do what they say on the tin, I might get say 3 to 6 months between recharges.

Other failed prototypes:

• Use a small latch solenoid. Wouldn’t move - too much side force
• Use a bigger latch solenoid (15N) . Wouldn’t move - too much side force
• Use electro magnets somehow like fire safety doors – too much power consumption.

Will post up a vid of it in operation shortly.

Can provide more detail if there is interest.

[samburner3 (Sam)]

Great, looking to do something similar.

@Mahko_Mahko
looks like the link to the AliExpress “Latching mechanism and main enclosure” is dead, can you link a new one or let me know what to type in search to find it?

Cheers

[Mahko_Mahko]

Try “rfid cabinet lock”. See below.

It’s still going pretty strong. But this was one of my earlier diy endeavours and I’d probably rethink it if I did it again. I moved to powering the lock with 2 x 18650 batteries and I get maybe 3 months between charges

[samburner3 (Sam)]

Ah great thanks found it!

Ah nice what do you use to control battery charging?
Maybe I should use an esp or similar and use wi-fi so then I can monitor battery levels maybe.

I’ll also need to weather proof this as it’s for a balcony door.

Thanks for the links and I’ll see what I can come up with

[Mahko_Mahko]

@samburner3

Maybe I should use an esp or similar and use wi-fi so then I can monitor battery levels maybe.

If you can power it from a cord then that opens up a lot of options.

If you can solar charge a battery in place that would be great too.

With the two above options you could use an ESP which opens up a lot.

You probably can’t use esp deep sleep for the project.

You can look at ESPlanty for solar battery ideas (including a waterproof enclosure).

ESPlanty | Self-watering Solar Powered Plant | No plumbing & no powerpoints | # Irrigation , # Deep Sleep , # Battery

[image] I kill plants so I decided to have my own crack at a self-watering plant. I call it ESPlanty. Key features: Solar/battery powered No plumbing required - Concealed water tank Moisture and light monitoring (light is handy for solar tracking too) Water tank and battery level monitoring More details: Photo’s of the base Irrigation rings I designed and printed Enclosure details (version 2, version 1 is in post above it) The jade plant cuttings seem to be going well! ESPHome config Des…

[Lend]

What would you change if you were to do this again now? I need something similar and this design seems really clever

[Mahko_Mahko]

Amazingly it’s still holding up quite well!

I swapped the 9v battery for 2 x 18650’s for better battery life. That gets it about 2months life. I’d think about what I could do to extend that life (or options to run power to it, which is tricky for my door).

If you could run power to it you might build a ESPHome solution.

The door generally doesn’t latch when closed, which is ok for me but not ideal. You might need a proper door closer to achieve that. Some of them you can configure to have a soft close but can have an extra little push for the last latching part.

I’d be keen to see what you end up with!

[antonio1475 (Antonio)]

Hi!
Any ideas to also open it? (slightly, about 20cm).

Explanation: I want to be able to let the cat in & out a balcony door that never actually latches and operates very smoothly, but its weight and wall design doesn’t make it easy to open for the cat.

So I kinda want to “push it slightly open” and then “push it mostly closed”.

Thank you!