CMPS14 Compass

[Stuart]

Thanks. Do I need to clear the nano memory somehow, or will this overwrite whats there?

[Cesar]

It will overwrite it. What version of Ago are you using? I’m not sure if it is v4 compatible

[Stuart]

4.3.1

!!

[Vili]

4.3.10 it’s compatible, V4_Upgrade is alpha of new version 4.6.20

[Math]

Hello,

@PotatoFarmer

Ok, if the are that imprecise open the window up to 10degrees is valid, every time you get back on the straight away the you can re zero their live value to their average. Commercial gps units had something figured out even in 2010, and I do not think their hardware was as good as AOG is now. So they must have figured it out with some post processing of data of some sort.

Don’t understand what you mean.

@PotatoFarmer

If you only have one sensor how do you know its truly drifting? Just like RTK having a base comparison to the rover, the extra receiver and some math allows you to reduce error greatly.

Long term drift of heading is not a problem as AOG use it as relative value and not absolute value.

@torriem

Sure. The problem previously was the BNO055 would drift for heading, although it worked okay as an inclinometer. So most people used a simpler sensor for terrain compensation (MMA something). Basically two axis inclinometer. The heading was determined from GPS. It worked pretty well for a lot of people, but not as well for others. Having a more accurate heading from the sensor is the goal here, as that will improve both the steering algorithms and the terrain compensation that’s already in AOG.

BNO055 3 axis accelero, 3 axis gyro, 3 axis magno, running its ones fusion algorithms to output yaw, pitch, roll angles. But what subject to short term drift. SO it’s why it was use only for heading, not for roll.
MMA : accelerometer, so it can output pitch and roll, but as it’s an accelero, it’s very sensitive to vibration, so output signal was noisy.
BNO08x/CMPS14 : same hardware than BNO055, but with more powerfull algorithm to output really more stable values.

@PotatoFarmer

T2 tech is actually more of a T0.66666. So it completely disregards an axis. Also the accelerometers are single Axis as well. I wish I had a T3 box to open up cause I am pretty sure now T3 is equivalent too one single 3 axis sensor if the pattern continues.

Don’t understand what you mean. As you posted before:
T2 : use 2 axis accelerometer + 2 axis gyroscope, so they can compute only 2 angles, pitch and roll
T3 : use 3 axis accelerometer + 3 axis gyroscope, so they can compute yaw, pitch, roll
Interesting information: Trimble doesn’t use magnetometer so it’s mean that they do not requiered a heading referenced to magnetic north.
It comforts me in the choice to operate the BNO085 in this mode (game rotation vector).
As Brian said before: you combine both of this 2 sensors to compasate each of their disadvantage . Adding magnetometer is for having a yaw referenced to magnetic north.

@PotatoFarmer

The single axis accelerometers AD22037 ADXL203CE are still worth a pile of money $23US each on Ali, the gyros are $135US on Brian’s link. So there is $316 worth of gyros an accelerometers in this box.

Finding gyroscope and accelerometer units it’s not the hardest part. The hardest part is development algorithms to fuse the data of this sensor and output stable and accurate yaw, pitch, roll angle. It’s why we are looking for IMU that are running their own algorithms and can provide rotation angle that “we just have to read”.

Math

[PotatoFarmer]

All I know is I am on to something cause, now i’ve got NDA.

Would love to refute but cannot.

[Mdmcurt]

Does an NDA pay decent money? Or how do they get you to stop looking

[PotatoFarmer]

Its very exciting for farmers, its a chance to work on some new technology.

[Mdmcurt]

That’s good, have fun working on new technology

[torriem]

An NDA is just a signed legal agreement governing the non-disclosure of information (non-disclosure agreement). It may involve monetary compensation, employment, IP, or anything else, really.

[rocket_troy]

I just purchased a CMPS14 for a project and have been playing with it. I thought I’d share some of my initial findings:
The module chews up significant current if set in serial mode - around the 27mA @5V in. That’s 135mW which can be substantial for some small battery applications.
The module needs 5V input to run in serial mode. 3v3 wont be enough to run correctly.
In i2c mode, the module consumes less power (maybe 10mA less IIRC). It can operate in this mode with a 3v3 input but the magnetic heading might be significantly offset from headings produced with higher voltage inputs. There is an onboard 3v3 voltage regulator which will output 3v3 down to say a 3v5 input. Below that, the output might drop 10mV (ish) per every 100mV drop in input voltage below 3.5v which unexpectedly does have a significant effect on the calibrated heading offset.
I’m guessing most people here will be powering it from 5V, but thought I’d provide a heads up in case as the datasheet does specify a 3.3v-5v input range.

BTW: I’m in the southern hemisphere (which might influence my readings, maybe not…)

[BrianTee_Admin]

Maybe you’ll have to turn it upside down!!

[cosmo]

Would it take much to add a second arduino and do the CMPS14 communications over USB so it’s not waiting for the PCB cycle, similar to how the brick brick functions?

[BrianTee_Admin]

The version coming up will allow that, to have an imu module.

[baraki]

I have already tested the CMPS14 and BNO085 on real equipment in the field.
Conclusions:
The BNO085 can be mounted anywhere and gives a stable course.
CMPS is very picky about the location on the tractor.
Roll CMPS14 is significantly faster than Roll BNO080 which has a slight delay, if you hold both in your hand and tilt it, you can see differences in reaction.

[Bada]

When not looking on the costs, what would be the better Hardware Equipment, or what Hardware Configuration promisse an better Autoguidance?
Dual Antenna vs. Single Gps & Cmps14
What are the thoughts?
Maybe the wrong forum, I dont know where to pur it else

[Stuart]

Interesting.

Where have you located your cmps for best results?

[andi]

Thanks a lot for this piece of information! I’m organizing an AOG workshop for 5 farmers in my area and right now I’m ordering all the electronics that we’ll need. I’m about to order the BNO085 for their initial setups. I prefer the BNO085 because,

• as I read we can place it inside the same box as the PCB,
• we don’t need to bother about the location of the box,
• we don’t need PCA9615 extension.

The only thing I’m worried about is the software. Is it only a modified .ino that allows for the use of the BNO085 or are there any other modifications required?

I assume you’re using BNO085 in Game Rotation Vector Mode. Could you provide the .ino that you are using? I’d be really thankful for that. Cheers, Andi

[Edit: I just found the Math’s github page with the .ino file for BNO085: GitHub - Math-51/Autosteer_USB_4.3.10_BN08x: Original AgOpenGPS Autosteer USB 4.3.10 adapted for BNO08x]

[Mechanic]

I just got my adafruit bno085. From what I understand I have to configure and upload Math’s bno08x.ino . But how to calibrate the bno085? I read the hillcrest sensor calibration procedure, but don’t understand what program to use to get there.
Can anyone explain how to set it up for AGopen in game rotation vector mode (so magnetic fields in cab won’t affect readings)

[CommonRail]

At the top of Maths ino he has all the settings, I just set 1 for roll, heading, and game rotation.

Personally I have put 3 Adafruit sensors in and never calibrate and don’t have any background calibration on. They just work out of the box for me.