BEA MS08U "Magic Switch": sensor won't stay clipped in

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asavage
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BEA MS08U "Magic Switch": sensor won't stay clipped in

#1

Post by asavage » 10 months ago

The BEA MS08U is a presense-detecting sensor that uses microwave technology to sense an object in its field of view. It's range is adjustable between 4-24". It's typically used to trigger a door operator (automatic door).

A problem I've run into is that people will be in the habit of slapping the shit out of a physical switch, and even though this switch clearly states, "Wave to Open", some people will still beat on it out of habit.

The wall plate is plastic. The sensor clips into it. If you flex the wall plate, the sensor can become unclipped. I've been fielding a lot of service calls for the sensor sitting in the wall box instead of clipped to the wall plate. I tried the fix below on three of them today; time will tell if it is effective.
BEA_MS08U_18b.jpg
BEA MS08U "Magic Switch" microwave presence detector.
BEA_MS08U_18b.jpg (287.73 KiB) Viewed 735 times
BEA_MS08U_03b.jpg
The bare wall plate & sensor.
BEA_MS08U_03b.jpg (529.46 KiB) Viewed 735 times
BEA_MS08U_04b.jpg
Sensor module un-clipped from wall plate.
BEA_MS08U_04b.jpg (539.86 KiB) Viewed 735 times
BEA_MS08U_05b.jpg
Sensor module snapped to wall plate.
BEA_MS08U_05b.jpg (622.15 KiB) Viewed 735 times
BEA_MS08U_06b.jpg
Detail of sensor module mount.
BEA_MS08U_06b.jpg (762.19 KiB) Viewed 735 times
BEA_MS08U_07b.jpg
Wall plate clip detail for sensor mount.
BEA_MS08U_07b.jpg (614.46 KiB) Viewed 735 times
BEA_MS08U_08b.jpg
Spool of copper wire (Nissan LD28 solenoid).
BEA_MS08U_08b.jpg (444.58 KiB) Viewed 735 times
BEA_MS08U_01b.jpg
3/8" hex nut, bandsaw.
BEA_MS08U_01b.jpg (846.05 KiB) Viewed 735 times
BEA_MS08U_02b.jpg
3/8" hex nut after bandsaw treatment: offset slot.
BEA_MS08U_02b.jpg (226.02 KiB) Viewed 735 times
BEA_MS08U_10b.jpg
Slotted nuts on copper wire.
BEA_MS08U_10b.jpg (777.36 KiB) Viewed 735 times
BEA_MS08U_15b.jpg
Copper wire fitted to top slotted nut, wrapped around wall plate plastic clips that retain solenoid module.
BEA_MS08U_15b.jpg (418.44 KiB) Viewed 735 times
BEA_MS08U_16b.jpg
View of lower nut.
BEA_MS08U_16b.jpg (664.89 KiB) Viewed 735 times
BEA_MS08U_13b.jpg
BEA_MS08U_13b.jpg (438.9 KiB) Viewed 735 times
Attachments
BEA_MS08U_11b.jpg
Assembled view.
BEA_MS08U_11b.jpg (189.57 KiB) Viewed 735 times
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

Carimbo
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Re: BEA MS08U "Magic Switch": sensor won't stay clipped in

#2

Post by Carimbo » 10 months ago

That seems like it should work. Even if the wall plate flexes, the wire still holds tension on the snap brackets against the sensor body.

I am most impressed by your camera's ability to finely focus on such close up shots. Which camera is it and what is your method?

waynosworld
Posts: 442
Joined: 6 years ago
Location: Vancouver Washington USA

Re: BEA MS08U "Magic Switch": sensor won't stay clipped in

#3

Post by waynosworld » 10 months ago

A quick fix that does the same thing without any prep is to use the 2 nuts and a zip tie thru the nuts, but your way will likely be more solid.
I know the voices are not real,
but they have some really good ideas.

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asavage
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Re: BEA MS08U "Magic Switch": sensor won't stay clipped in

#4

Post by asavage » 9 months ago

Caxambu: yes, I'm hoping that when folks smack the front of the wall plate, even though the center of the wall plate flexes in, and the tension on the molded-in tabs holding the sensor module clipped in is diminished, the copper wire wrap will retain the sensor module.

In the past, I just used the copper wire, but it didn't work because there was no tension on the black molded clip arms; they weren't getting any tension from wire, since the clips are narrower than the sensor module. That's what the 3/8" nuts are for: to get the tension to the back of the clips.

I took those pictures with an iPhone SE, which is like a iPhone 6Plus except it's got the physical form factor of a iPhone 4 (smaller, that is). It's a fairly poor camera, in my opinion, with the macro focus only fair, but if you stay out at least one foot or more, it works OK. I post-process in software, which helps.

The built-in flash is especially bad on shiny surfaces, but that's the nature of one-size-fits-all LED flash units. However, the phone is always on me, so I tend to use it for low-importance tech shots. If I'd doing anything important, I use my Nikon Coolpix or my older Samsung TL110, which does quite good macro shots.

These pics are helped by the color contrast of the parts being photographed.


Wayne: nope, the sensor is wide enough that the added width of even small nylon wire ties will prevent it from installing in the wall box. Same problem if I turned the nuts sideways: too tall, won't clear the metal sides of the wall box.

Commercial wall boxes are metal and have folded-over aperture design, so the opening is smaller than, say, a metal rework box or a residential plastic box.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

User avatar
asavage
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Posts: 5331
Joined: 14 years ago
Location: Duvall, Wash.
Contact:

Re: BEA MS08U "Magic Switch": sensor won't stay clipped in

#5

Post by asavage » 7 months ago

I had another one today, same problem: they hit the face plate hard enough to flex the paint off the back. The clear plastic is painted on the inside, and the paint is not as flexible as the plastic.

Despite the appearance, the plastic is not cracked, only the paint.
BEA_MS08U_19b.jpg
Hit hard.
BEA_MS08U_19b.jpg (363.86 KiB) Viewed 624 times
BEA_MS08U_20b.jpg
Paint came off the back, due to flexing of the plastic.
BEA_MS08U_20b.jpg (340.65 KiB) Viewed 624 times

I used the same method to repair, though I replaced this wall plate with a spare. And I cut the slots in the nuts wider (two passes with the bandsaw), so the wire isn't as tight to fit in the slots.

The pics I took above were very helpful in reminding me what I'd done the last time. As you get older, notes to self become more important.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

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