Mongoose AHRS firmware and PC GUI are ready

The first version of the Mongoose AHRS (Attitude and Heading Reference System) firmware and the PC GUI (with VB.net source code) are both working and are available for download on the website. There is still a bit of work that needs to be done to make sure the soft iron compensation is working, but for the most part it is working pretty well.

10 thoughts on “Mongoose AHRS firmware and PC GUI are ready”

  1. I’m about to start building my first quadrotor and Mongoose looks like an awesome component to include. Can you provide some info on how you are connecting it to the PC to run with the software? Do you connect it directly to the Mongoose or via an Arduino? I’m more of a software developer than an electronics engineer so feel free to include pictures. 😉 Thanks!

  2. Mongoose definitely has all the sensors you need for a quadcopter. It can connect to anything with a 3.3v serial (UART) port. The roll, pitch, yaw and other sensor data is sent as an ASCII string of comma separated values over the serial port to whatever you have connected. So to answer your question, in the video I have it connected to the computer through a simple USB to UART converter, no separate Arduino board is needed. The converter I’m using is just a cheap one I picked up on Ebay, but something like this would work.
    We are working on our own USB to UART adapter based on the FTDI FT232RL but it wont be available for another few weeks.
    I’ll be putting up some pictures and connection diagrams in a basic user guide later this week so be sure you check back then.
    -Cory

    1. The TTL-level of the USB-UART cable is 3.3V, but Vcc of most(all?) FTDI cable is 5V. No problem to connect it to the serial port on the mongoose which has a 3.3V pin (it works in your video with just connecting the board to the computer through the USB converter and no additional power)? The 3.3V on the user pins will be 5V then, too?

      1. The Mongoose is operating at 3.3v, so driving an input to 5V will damage the onboard Atmega328.
        In the video, I’m using a USB to UART converter that talks at 3.3v and also supplies 3.3v to power the Mongoose board.
        Most (including the FTDI FT232RL) USB-UART converter chips have a built-in 3.3v regulator so that you can choose to operate their IO at either 3.3v or 5V depending on what you are connecting it to.
        -Cory

  3. Seems to be a small bug in the AHRS firmware during handover of the calculated pressure, which leads to wrong values of the pressure in the serial output:
    “short Read_Pressure()” should actually be “long Read_Pressure()” in BMP085.pde

  4. Hi Cory,

    Mongoose looks great…quick question:

    How hard would it be to hook it up with an xbee to program it wirelessly?

    I’m mainly a software guy so just want to check before I pull the trigger and buy the board 😉

    Also, what’s the shipping to London, UK?

    Cheers //O.

  5. I just received my Mongoose, when running the GUI I had to flip it upside down to get the horizon correct. The sensors were facing down and the Mongoose V1 writing is facing up.
    Is this the correct orientation?

    1. Yes, it is correct. The convention for aircraft is to have the Z axis point down, and the X axis to point forward. While Mongoose doesn’t have to be used in an aircraft, we thought we would stick with that convention just to avoid confusion. If you go into the visualizer code, you can just add 180 to the roll angle if you want “up” to be the component side.
      -Cory

      1. I’m about to start building my first quodrotar and Mongoose looks like an awesome component to include. Can you provide some info on how you are connecting it to the PC to run with the software? Do you connect it directly to the Mongoose or via an Arduino? I’m more of a software developer than an electronics engineer so feel free to include pictures. Thanks!

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