# Interfacing Arduino to Fathom S Topside

**URL:** <https://discuss.bluerobotics.com/t/interfacing-arduino-to-fathom-s-topside/1939>\
**Category:** Communication Interfaces\
**Tags:** fathom-s\
**Created:** [January 2, 2018, 8:45pm UTC](https://discuss.bluerobotics.com/t/interfacing-arduino-to-fathom-s-topside/1939 "2018-01-02T20:45:58Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Mewtwo](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/mewtwo/32/2029_2.png) [@Mewtwo](https://discuss.bluerobotics.com/u/Mewtwo)\
**Post date:** [January 2, 2018, 8:45pm UTC](https://discuss.bluerobotics.com/t/interfacing-arduino-to-fathom-s-topside/1939/1 "2018-01-02T20:45:58Z")

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I am trying to use the Fathom S for an ROV I am building. I would like to use an arduino to interface to the topside board instead of a computer. I tried to use the arduino usb host example code for ftdi, but it did not seem to produce an output signal on the tx. When I use my computer to interface to the topside board, I can get a signal on the tx pin. Does anyone have experience using the topside board with an arduino and is using a usb host shield the preferred interface method?

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**Author:** ![jwalser](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/jwalser/32/2234_2.png) [@jwalser](https://discuss.bluerobotics.com/u/jwalser)\
**Post date:** [January 2, 2018, 10:04pm UTC](https://discuss.bluerobotics.com/t/interfacing-arduino-to-fathom-s-topside/1939/2 "2018-01-02T22:04:55Z")

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Can you share the shield you are using, your code, and how you have things wired?

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**Author:** ![Mewtwo](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/mewtwo/32/2029_2.png) [@Mewtwo](https://discuss.bluerobotics.com/u/Mewtwo)\
**Post date:** [January 2, 2018, 10:59pm UTC](https://discuss.bluerobotics.com/t/interfacing-arduino-to-fathom-s-topside/1939/3 "2018-01-02T22:59:20Z")

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This is the link for the USB host shield running on a mega 2560:  
[https://store.arduino.cc/usa/arduino-usb-host-shield](https://store.arduino.cc/usa/arduino-usb-host-shield)  
This is the code:

> **[GitHub - felis/USB\_Host\_Shield\_2.0: Revision 2.0 of USB Host Library for...](https://github.com/felis/USB_Host_Shield_2.0)**
>
> Revision 2.0 of USB Host Library for Arduino. Contribute to felis/USB\_Host\_Shield\_2.0 development by creating an account on GitHub.

We used the library manager in arduino to add the USB host code.  
We used the USBFTDILoopback example.  
We used a scope probe to check activity on the tx pin of the header.  
We have screw shields providing optionally 12V, but that does not seem to effect the result.