Make a Dumb Air Freshener Smart With Shelly Device

Beautiful design, flawlessly fitting to almost any kind of interior, many different scents not only refreshing the atmosphere but also setting a tone for a good mood, all of which at a reasonable price is what you get from an automatic air-freshener. However, if you, like me are a proud owner of at least one of them, you might also have experienced some of the following disadvantages:

• The maximum spraying time (36 minutes) is way too frequent
• The minimum spray time (9 minutes) is sometimes too long
• The need to spray manually - reaching over for the freshener and pushing the button on the back most often is inconvenient
• There are no any affordable smart air-fresheners
• Daily manual turn-off during the night, to ensure quite and calm atmosphere
• Frequent purchases of the spray refill, because of the predefined spray time
• Disposing of the drained batteries to designated places

The ultimate goal is to modify the air freshener so that the spray time can be modified, which does not work at night and when I would like - set a schedule, individual spraying, and/or a pre-determined pattern, as well as controlling it remotely! So, I was interested in accessing it via Internet and through Alexa.

For that purpose, I has chosen Shelly Uni automation device, since:

• It has two outputs - the first, I am will be using for switching on/off the device, the second one, for accessing the manual spraying button
• Eliminating the two AA (2x1.5V) batteries, since Uni has 3.3V Output designed for external sensors' powering, but it is perfect for powering the freshener
• Uni perfectly fits at the place designed for the batteries

The only sacrifice will be that it will already need power to the mains and will not run on batteries, but we will stop changing the batteries!

You can find more information about Uni here: https://shelly.cloud/products/shelly-uni-smart-home-automation-device/

The best thing is that there will be no need to re-solder or change components, and I will keep all the functions so that the device can work in the standard way, if desired.

I will use Glade, which I chose for the exterior design, but judging by the PCB circuits from the Internet, the principle of operation is similar to Airwick.

We will also need a power supply, as Uni supports AC 12V - 24V and DC 12V - 36V.

Remove the batteries and disassemble the air freshener by unscrewing the bolts.

Inside there is a mechanism with a motor that presses the spray, a button for manual spraying and a PCB with a switch to select the time-plan or switch off.

I have two air-fresheners that look the same (they differ only in that one has holes for hanging on the wall), but with different schemes, motor and buttons. Judging by the inscriptions, one is a newer version. I will use the old version for demonstration, but the principle is the same for all air fresheners with a timer.

I will use one Uni Output for short between Off and 36 min. Thus, when we move the switch of the option for 36 minutes, if the Uni Output is on, then the Glade will not work, and if Uni Output is off it will spray every 36 minutes, by default. The other options - 18 and 9 minutes will work as usual. We will name this output in the "Glade Disable" application.

The other Output will be connected to the button. Then the output, if turned on, will spray once. We will call this output "Glade Spray" and set it to Auto Off timer in the app after 1 second.

We will connect the yellow cable (VCC 3.3V output) to the + of Glade, and the green to the minus of Glade. In principle, the idea of these is to power the external sensor, but they are quite sufficient to power the air freshener.

I prefer to solder the cables to the PCB and run them from to the body of the air freshener, then connect them to Shelly Uni, which will be placed in the place of the batteries.

However, the cables can be connected directly to the buttons by twisting. One can also use the test points on the PCB.

The orange cables are for the "Glade Disable" output and the black for the "Glade Spray".

I screw back the body bolts.

I drill a hole at the bottom to get the power cable from the 12-volt adapter. Alternatively, the holes for hanging to the wall can be used, if any.

I remove the battery plates and the barrier in the middle with a drill and knife.

The routed cables need to be connected to the Uni and with the help of double-sided adhesive tape (or hot silicone) we fasten Shelly Uni in the place of the batteries.

It should be noted that behind the refill-bottle there is a lot of space for cables, for the antenna of Shelly and even for another Shelly

Turning on the adapter and connecting the Shelly to WiFi network, through the Shelly Cloud App for Android or OS.

Here you can find the instructions: https://shelly.cloud/documents/user_guide/shelly_uni_multi_language.pdf

When the power is turned on, my Glade sprays once by default.

The first thing I do after connecting Shelly to the internet is to update the firmware. I name the two outputs - Glade Disable & Glade Spray and then test.

I have prepared some sample scenes that I use at home:

• Spraying every hour and a half during the day, but not at the night - in the Shelly app
• Every 90 minutes from 10:00, until 22:30:
• Turn off "Glade Disable" (power on freshener)
• Push the button after 5 seconds (my Glade needs some time to power up)
• Turn on "Glade Disable" (power off freshener)
• Spraying repeatedly (3-4 times) with manual activation - in the Alexa app, when I say "Alexa, spray" or "Alexa, make Living room fresher"
• On voice command:
• Turn off "Glade Disable" (power on freshener)
• Push the button after 5 seconds (3 times)
• Turn on "Glade Disable" (power off freshener)

And now we have a smart air freshener at home! Believe me, it is very convenient.

P.S. I think there is a way to find out if the bottle is empty with Uni outputs.