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Exposed: LEGO Ultrasonic Sensor

This one was a request by one my readers and what a great suggestion! Taking this sensor apart proved a little bit of a challenge.  It wasn’t as eager to give ups secrets as readily as some of the other ones I’ve opened up in the past.  I also didn’t have a replacement cap for this, so I had to be careful.

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The plastic frame to the left actually sits inside the main part with the “eyes” and looks like it would be for holding in the receiver and transmitter but it’s not.  I have no idea why this thing is in there. Edit: It has small tabs on it that click into the piece on the right. You can see the two transducers, one’s a receiver and the other’s the transmitter.  Can you guess which is which?  They’re super stuck in there.  I tried to pry them out to no avail.  The two little holes in the middle are for holding the screws for the small plastic frame on the image on the left.


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The top side of the PCB.  The connector is on the left and there seems to be a cloaked processor or  other device under that blob.  I am guessing it’s alien technology and the government (and LEGO) don’t want us to know. The reverse side of the PCB.  You can see the wires going to the transducers and what appears to be a crystal and another processor.  They really stuffed this side with components.


So now you know what the LEGO Ultrasonic Sensor looks like on the inside.  If there’s another sensor you’d like me to take apart so you can see what’s inside, let me know and I’ll see what I can do.

About Xander

Xander Soldaat is a Software Engineer and former Infrastructure Architect. He loves building and programming robots. He recently had the opportunity to turn his robotics hobby into his profession and has started working for Robomatter, the makers of ROBOTC and Robot Virtual Words.