VectorNav VN-100 AHRS use with arduino?

Hello,

Has anyone used the VN-100 Rugged (or SMD) with their project successfully? Does VectorNav support using this AHRS with Arduino or other microcontrollers?

Thanks,

Jack

It should be no problem at all to interface the VN-100 with any Arduino, as it offers standard RS232 serial or SPI serial output.

Remington,

How would you go about using the RS232 Serial communication method?

Have you tried this? First link in google.

If the voltage levels are true RS232 (inverted, +/- 12V) you will need an RS232 to TTL serial adapter, like this one. Check the VN-100 data sheet or user manual.

dyso, yes I did see that page. It seemed limited to me.

Remington, thanks for the tip, I'll keep it in mind moving forward.

Remington, see pin 8 and 9

vn-100 screenshot.PNG

vn-100 screenshot.PNG

Since it inputs and outpust at the TTL voltage level, does this mean that no adapter is needed Remington?

Well, the adapter wont fit anyway. It is a 9 pin connector. You would have to make a conversion. To me, it looks like you are correct. I would just test those 2 pins, they are 3.3V so it shouldn't be a problem.

Btw, where can you buy this IMU? I would like to have one myself.

Since it inputs and outpust at the TTL voltage level

No, it doesn't. The specification is misleading. "TTL" is 0 to 5V.

TX1/RX1 outputs and inputs "RS232" levels, which means -5 to -20V and +5 to +20V. For this you need an adapter like this one.

TX2/RX2 outputs and inputs 0 and 3V, which is marginal for inputs on a 5V Arduino (3.6V is guaranteed to be HIGH), but it often works. Better to use a 3.3V Arduino.

dyso,

Thanks for your input, according to Mr. Gamagedar (the person's repository that you suggested) we are right. Although his code seems limited, my second thought is that it is merely nice and simple. Although it may be hard to figure out how to get quaternions out of the IMU. Here is his response to my asking how he did his connections:

"We use the rugged version too, and you can directly connect pins 8 and 9 to any 3.3V Arduino board like Due or Zero. In case you are not familiar, Arduino boards come with microcontrollers with different operating voltages (this is different from the Arduino board's input voltage), and the RX/TX pins on the Arduino board must be 3.3V as VN100 RX/TX pins are 3.3V pins. Here is a complete list of Arduino boards and their operating voltages.

If you have a 3.3V board, directly connect the RX/TX pins. If you have a 5V board, you have to use a bi-directional level shifter like this in between the IMU and the Arduino board for RX/TX. All together you need 4 connections:

  1. IMU Pin 1 (VCC) to Arduino 5V output pin
  2. IMU Pin 8 (TX2_TTL) to Arduino 3.3V RX pin
  3. IMU Pin 9 (RX2_TTL) to Arduino 3.3V TX pin
  4. IMU Pin 5 (GND) to Arduino GND pin"

Remington, it appears no adapter is needed if pins 8 and 9 are used from the rugged version, but indeed, the board must use 3V logic, I think my teensy 4.0 should be a good substitute since it uses 3.3V. But sparkfuns logic level converter could always be used to use it with any 5V arduino according to Mr. Gamagedar.

jremington:
TX2/RX2 outputs and inputs 0 and 3V, which is marginal for inputs on a 5V Arduino (3.6V is guaranteed to be HIGH), but it often works. Better to use a 3.3V Arduino.

@jack732, If you're using a 5V arduino, you could just make a voltage divider by using resistors. But you probably already know that.

I think my teensy 4.0 should be a good substitute since it uses 3.3V.

Excellent choice!

dyso,

I believe I read that somewhere as a workaround to the logic converter, although I wonder if it's really that simple as the converter from sparkfun seems a tad bit more complicated than a few resistors. I know little about logic conversion so I'll just make a note of your suggestion in case what I have doesn't work. Thanks.

Remington,

Glad you agree!

I'll update this thread if I get any more useful info. Have a good night you two.

If you are sticking to the Teensy, then I would ignore what I wrote. You can connect it directly.

It's only important if you switch to a 5V Arduino. I assure you, it is that simple.
Here is an example:

Also, FYI, if you are deciding to power up the teensy on an external power source. Be careful. Follow the instructions:
https://www.pjrc.com/teensy/external_power.html

dyso,

Thank you very much for this diagram, I'm not exactly the most electrically oriented person so it helps a lot. And it's reassuring to know that it is that simple, I wonder why sparkfun decided they needed such a complicated looking chip for something so simple.

haha, I spent like an hour and half trying to figure out the best (lightest) way to power the teensy 4.0. I actually settled on a super small phone charger so I can power it directly through the micro usb while saving as much as possible on weight. A little lipo battery could probably power it for much less weight but 30 grams doesn't hurt the design too much so I'll just leave it at that.

By the way dyso, the VN-100 rugged with temperature calibration (so you can use it in freezing weather I suppose) actually costs $1100 not 500. I saw a list of the official prices. It's the surface mount version (which ain't plug an play) that costs $500 without temperature calibration. bro it probably cost them $20 to make it xD

Oh wow. That's very expensive. I hope it's worth it.

jack732:
I actually settled on a super small phone charger so I can power it directly through the micro usb while saving as much as possible on weight.

As a matter of fact, that is how I power my teensy 4.1. I was considering cutting the pad, but I can't be bothered.

"I hope it's worth it"

yeah I hope so too, there is a 30-day money back return policy so if it ain't all it's cracked up to be guess who I'm sending it back to.

"As a matter of fact, that is how I power my teensy 4.1..."

good deal.

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