Hi there,
I'm looking for some help in designing a PCB that houses multiple inline ST Microelectronics VL6180X sensors. I've tried several iterations in an attempt to reduce the footprint to the smallest size possible:
1. The first version was based off of the Adafruit VL6180X breakout board. This iteration was broken into two boards. The top board only houses the sensors on top with a set of male header pins on the bottom. The bottom board houses all of the components from the Adafruit breakout board in which the board is double-sided. When attached to an Arduino, the software always fails to initialize the last sensor in the string, regarless of how many sensors I am attempting to initialize (the software works for an array of Adafruit breakout boards).
2. The second version was based off of this project that I found on the Hackaday website ([https://hackaday.io/project/163920-a-halo-for-lucy/log/162154-the-second-pass-prototype](https://hackaday.io/project/163920-a-halo-for-lucy/log/162154-the-second-pass-prototype)) in which the author used the VL53L0X sensor (similar to the VL6180X). This is the schematic that was used in the author's project vs. the schmatic that I used for my own project.![](https://cdn.hackaday.io/images/2986291555791899093.jpg)![image.png](//image.easyeda.com/pullimage/NshXC1RxsW3U9su7VdCSsbHNdMnXVeq3kKY4Aeqh.png)
I've found an application note from ST Microelectronics ([https://www.st.com/resource/en/application_note/an4478-using-multiple-vl6180xs-in-a-single-design-stmicroelectronics.pdf](https://www.st.com/resource/en/application_note/an4478-using-multiple-vl6180xs-in-a-single-design-stmicroelectronics.pdf)) that offers this schematic detailing how to add more than one sensor to the same board:
![image.png](//image.easyeda.com/pullimage/zbtDi6JcJ3SFBhcaGoQsOUpJoDts61fVcBwIv2Sn.png)
Note: The GPIO pins referenced in figure 3 are the same as the XSHUT pins in my schematic. Instead of the GPIO expander, the sensors are connected directly to an arduino Mega 2560.
Could anyone tell me how far off I am in my design/point me in the right direction? Any help would be much appreciated - thank you!