This post is a part of the Hiding Hardware Initiative. Feel free to check out that post for more guides to come on hiding hardware, or to add your own contribution.
As part of this initiative I decided to paint my contact sensors the same color of the window and door frames of our house. Windows and doors are expensive and so I didn’t want a white plastic ‘pimple’ ruining the look of the (in our case black) window and door trim.
Below is the process I’ve gone through to disassemble and paint them.
Disassembly is for the Aqara E1 contact sensors, so yours will be different depending on the sensors you have, but painting should be the same for everyone.
– You’ll need: –
- Plastic or metal opening tools (I suggest getting an iFixit kit or similar). In a pinch, you can probably use a small knife.
- A pair of tweezers
- Painters tape
- Sharp knife
- Fine sandpaper (600 grid or higher)
- Spray primer
- Spray paint to match the sensor location (window trim color, …)
- Optionally
- Respirator RECOMMENDED (paint fumes and overspray are NOT healthy)
- Heat gun
– End result: –
A painted sensor versus a new one.
As you can see, the sensor doesn’t stand out as much anymore. from a distance you can barely see it on the trim.
– Disassembly (Aqara E1 contact sensor) : –
The smallest of the two parts is the magnet in its housing. Since this is a passive part, we will not be dismantling it before paint. You are also not obligated to use the magnet that comes with the sensor. Any magnet will do and stronger ones will even extend the range over which the sensor will be ‘closed’.
Step 1:
Remove the blue battery tab. You can throw this in the trash.
Also remove any stickers as they will prevent paint from sticking later on.
Step 2:
Lift the bottom part off the sensor by inserting your finger in the provided cutout. You can also use a plastic opening tool or small knife.
Step 3:
Remove the coin-cell battery.
Step 4:
Insert a thin opening tool or small knife on the opposite side of the battery, between the grey plastic insert and the housing. Lift up GENTLY until the insert pops loose.
Step 5:
Insert the tool on the long side of the sensor, between the grey plastic insert and the sensor housing. Lift GENTLY until the insert side pops loose. Repeat on the opposite side.
Step 6:
The grey insert will still be held in place by 2 locating pins. We’ll remove that later.
For now, bend it upwards gently and remove the electronics with some tweezers or small pliers.
Set the electronics safely aside.
Step 7:
Loosen the locating pins on the front by inserting your opening tool underneath and leveraging upwards.
Step 8:
Using tweezers, remove the clear LED pillar and set it aside.
Do not lose this part. I recommend taping it to the electronics with some painters tape until you need to reassemble everything.
Reassembly after painting:
Follow the disassembly steps in reverse.
After you reinsert the LED pillar, you can drop in the electronics. They have 2 locating pins to help you.
– Painting: –
Step 1:
Tape the button in place, so it does not move during sanding and painting.
Alternatively, you can remove and paint it by itself, but I found that not necessary and since it’s a small part, you just run more risk of losing it.
Step 2:
Reassemble the sensor housing without the electronics inside. This will negate the need for taping off the insides.
Step 3:
Mask off the underside of the sensor and magnet, where the mounting tape will be placed. You don’t want paint here as it can cause problems with adhesion of the mounting tape.
The easiest way is to put a piece of painters tape over the entire bottom piece and then cut out the shape with a sharp knife.
We want to paint the outer rim as well, to make sure none of the original color is showing on the sides.
Step 4:
Use your sandpaper to rough up all surfaces. Be careful with sandpaper as it’s aggressive so you could round over the sharp edges of the sensor (only an aesthetic concern though).
Step 5:
Clean off all the sanding dust with a lint free cloth. The goal is to get all the dust off since any remaining will prevent good adhesion of the paint.
Step 6:
You’re ready for paint!
We’ll start with a primer basecoat. Depending on the primer, you’ll need two coats.
The first coat is on the bottom side. For subsequent coats, put the part right side up. This way you make sure not to leave a gap around the bottom of the sensor where the original color can show up.
Spray from all sides to get even coverage.
TIP: for better results you want to put on light coats. Don’t spray directly at the part, but rather: start spraying just next to the part and move the can in a line perpendicular to the part. Release the nozzle once you’re past the part. Repeat as needed.
Step 7:
When the primer is dry, we can add our paint.
Spray in the same way as you put on the primer. Multiple light coats give the best finish. I needed 3 coats for full coverage.
My windows are aluminium frame, powder coated in a matte RAL9005 finish, so I’ve gotten the matching spray paint for that. Of course, change this to suit the environment where you’ll be placing the sensors.
TIP: depending on the paint, drying between coats can take a couple of hours. You can speed this up by using a heat gun. Be VERY careful here, we’re dealing with plastics, so be careful not to melt your parts.
– Finishing –
Leave the last coat to dry for at least 24 hours. This way the layers will harden fully and will give you less risk of chipping when reassembling the sensor.
Don’t forget to remove the masking tape on the bottom.
After this, you can reassemble following the steps in the first part in revers and voila: you have a working contact sensor in the color of your choice!
