Structure principle of micro ball vibration switch with chip

tb I saw a shop called jingyixin selling this kind of miniature ball vibration switch , Space is limited , I don't want to use MEMS In the case of gyroscope, it can be used to replace the ordinary cylindrical ball switch . It looks a little like 1206 Self recovery insurance , Just thicker . I tried it after I got it , It feels a little more sensitive than an ordinary ball switch , Not bad .

Structure principle

The action principle in the specification book doesn't mention the specific structure , Since it is a mechanical switch based on ball , It must have the same limit of switching angle as ordinary ball switch , So I took the electric mill and opened it to have a look at the structure .

In the middle of the caliper is the vibration switch , This picture is only worn off the surface . You can see , There's a downward stretch of something in it , It should be copper foil , Or copper strip . It is connected to the electrode on one side , It's the semicircular depression above . Keep grinding ：

You can roughly see the principle . There is an opening where the arrow points , In the hole is the body of the ball . The metal ball is placed in a metallized hole , The hole walls are all conductive copper , Connect with the electrode below . There should be an insulating layer between the conductive part of the hole wall and the copper strip in the first figure , The copper strips on both sides are connected to the upper electrode , So the metal ball can connect the upper and lower electrodes . When the ball moves due to vibration , The connection of electrodes on both sides will also be intermittent , This realizes the effect of detecting vibration . The whole is actually similar to a small piece of four layers PCB, The material is also similar to PCB equally . The schematic diagram is as follows ：

This is the section cut vertically , The orange part is copper foil , The upper and lower sides are electrodes at both ends , Purple is metal ball , The part without a slash in the middle is an opening . Because of this structure , When lying flat, the switch is always on , But it may be because the ball is in point contact with the middle hole wall , It is easy to be in bad contact due to disturbance , It also detects the vibration . When the switch stands vertically as shown in the figure , The actual measurement shows that the switch is almost always disconnected , It will also become very slow to vibration . Guess it may be in the vertical state , The friction between the hole wall and the metal ball is relatively large . Or when the orientation of the hole is horizontal , Encounter vibration , The metal ball will bounce off immediately if it is hit at both ends , Then stop in the middle because of friction , So it seems that there is no response to vibration by visual inspection .