MB1260 XL-MaxSonar-EZL0 Teardown

[Charles Creations]

Hi Everyone,

I did a teardown of a MB1260 XL-MaxSonar-EZL0 made by MaxBotix, and despite their pictures on the website, the top of the board is encased in a cured silicone compound. This made the teardown very destructive, so I thought I would share my results to prevent others from having to do the messy task of removing the silicone.

Quick Specs:
-10Hz Update
-5V or 3V3 Supply
-Max Range of 10m
-42KHz Ultrasonic Frequency
-1cm Resolution
-4 layer board with power and ground plain internal (all signals on outside)
-46Vpp transmit pulse with 500us pulse length at 42KHz


The unit looks like this:




Explanation of Attachments:

"Capacitor Map"
This shows the location and value of all capacitors. Some were too small to be measured with my meter, so they have a question mark.

"Resistor Map"
This shows the location and value of all resistors. They were measured in circuit, so may have errors.

"ICMap"
This shows the main ICs. Notably, there is a L324A quad opamp, a PIC16F690 microcontroller, and what I believe is a BJT package being used as a diode.

"50%OverlayFlat"
This is an image of each side of the board overlayed with transparency, so you can see where vias connect on the far side.

"Schematic"
This is a crude schematic of the circuit I put together. It is not complete, but it gives the general gist of it. Of note, the sense line for the amplifiers is not switched on after the transmit pulse, so the design relies on the high impedance of the resistor and op amp input to protect it from overvoltage. I measured almost 46Vpp on the output with my oscilloscope. The labels "A#" refer to the pins of the the PIC, so the PIC's pin 1 is A1.