X,Y,Z IMU (accelerometer, gyro and compass)

Timmoore

This is a 9DoF IMU, it uses a tri-axis accelerometer, 3x single axis gyro and tri-axis compass.
The accelerometer is the ADXL335, the gyros LISY300AL and the compass the HMC5843. You can build this the breakout boards from sparkfun
http://www.sparkfun.com/commerce/product_info.php?products_id=9372
http://www.sparkfun.com/commerce/product_info.php?products_id=9373
http://www.sparkfun.com/commerce/product_info.php?products_id=9371
though I dont use this LISY300AL board.
It has also used with an ADXL330 accelerometer, 2x dual IDG300 gyros, CMPS03 compass with no code change to the IMU code
It uses a cutdown version of cessna's fixed point maths library, tuned for the IMU.
It has a I2C object for the HMC5843.
It uses a TLV2553 for the A2D, this is a faster version of the TLV2543. This A2D will work with the obex tlv2543 library but the object here is tuned for the tlv2553/tlv2556 and runs much faster - it samples at ~9000 samples/sec for each of the 11 channels
The IMU started from Jason Wood 5DoF IMU but runs an additional kalman filter for the Z axis. I have also moved the A2D access external to the object so other A2D/accelerometers/gyros/Compass can be used without changing the IMU code - also the midpoint and gyro gains are passed in during initialization.
The IMU updates at ~48 times/sec and uses 1 Cog for imu(imu, kalman filters and maths) + 1 cog for the A2D

simonl

WOW! Great work! I'll have to try this when I can get the parts

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Cheers,
Simon

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Timmoore

One comment that I didn't mention above though its in the hmc5843 spin file. I used the Sparkfun breakboard but I had to mod the board to make it work. There is a 10uF cap on the board (C3 on the schematic). I added in parallel a 100uF cap before it would work. I think I saw this mod on the diydrones forum, it seems others have had this problem. I2C sometimes responses but the magnetic values are garbage. Adding this cap made it work immeditely.

Burk

You say C3 on the schematic is 10uF, don't you mean 0.1uF? I seem to have issues with my HMC5843, on the honeywell product page some people talk about the big(ger) black cap but that is C1 on the schematic. Adding a cap parallel to it doesn't do a thing but make the HMC5843 hang on some attempts. Where's C3 on the board anyway? Looks like it aint there at all...

Cluso99

@Timmoore: This will be a great start for the pcb I am doing with the new ITG-3200 3axis gyro plus the ADXL345 & HMC5843. I must check the diff of the ADXL335 to 345.

What are you controlling? Do you have a pic?

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Links to other interesting threads:

· Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
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My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz

Timmoore

@Burk, This maybe fixed in the latest breakouts from sparkfun, I have seen reports on their website say that. If not on the picture on http://www.sparkfun.com/commerce/product_info.php?products_id=9371
The black SMT cap oppersite side of the board from the connector is the cap I put another one in parallel with. In terms of C1/C3 which schematic were you looking at, on the honeywell datasheet its C1, I think it was C3 on the sparkfun schematic.

@Cluso99, I had to put it on one side for a while due to work and other stuff. I have started picking up my bot stuff again though I haven't got to that yet. I dont have a picture of it but I can take one and post it. The code is setup so the sensors and kalman filters are separate and link through hub varables, so its easy to change the sensors without changing the filters. There is some configuration tables that·specify the gains of the sensors so if you change the sensors, you can change the config table and the filters will work unchanged.
Its currently an overkill for what I use it for - bot navigation but most of my bots use one set of code and are configured for H-bridge, sensors etc. so the idea was to integrate it into by code framework and its easy to use on any of my bots. I dont see any major issue changing it for the different accelerometer and gyros.

Burk

OK thanks. Just to be sure, 100uF electrolytical right? (otherwise it would be the size of a beer-can probably)... and when viewing the board from the component-side, connections to the left, cap on the right, the lower contact is the ground right?

Timmoore

@Burk, I would have to check the board to be sure but it looks that way from the photo. I used a 100uF electrical because I had it to handle even though it was a bit big. There is a report on sparkfun some people used

Digikey PN PCC2395CT-ND / ECJ-1VB0J106M
Panasonic ECG Ceramic 10uF 6.3V X5R 0603.
Small, lowESR

with success

Burk

Thanks, i'll try later. Did you get any data from it before that cap? I do but it's kinda random and not responding to rotating the sensor like:

x:4128 y:256 z:8192
x:5119 y:-1 z:-1
x:4128 y:256 z:8192
x:4128 y:256 z:8192

Timmoore

That sounds familar, it was reading teh sensor but the values didn't make sense.

Cluso99

Re the capacitor problem. Are you sure the problem isn't really bring in 3v3 from an external connector and this requires more than a 100nF cap?

Thanks Tim. Yes the prop rocks for these apps because the code can be segmented easily with multiple cores.

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Links to other interesting threads:

· Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
· Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz

Timmoore

@Cluso99, there is a comment in the HMC5843 datasheet that the caps needs to be low ESR. There were several issues across different implementations using hte HMC5843 - sparkfun, diydrones and Surveyor that found that this was critical for C1 (datasheet). If the cap wasn't low enough ESR puttting a large value cap in parallal to it helped.

Cluso99

@Timmoore: That is really only commonsense to professional designers. The datasheets point this out. It is a note to the unwary though.

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Links to other interesting threads:

· Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
· Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz

mctrivia

Timmoore this is a great design. I am planning a 4 layer pcb panel maybe we can design a good 9DOF breakout with everything together in one board.

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Lots of propeller based products in stock at affordable prices.

Cluso99

mctrivia: see the quadcopter thread. I am doing a 10+dof and prop on a pcb already.

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Links to other interesting threads:

· Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
· Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz

mctrivia

ok. no reason to reinvent the wheel.

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Lots of propeller based products in stock at affordable prices.

Cluso99

Yes. Sorry I didn't mean to sound harsh :-(

I have the newly released gyro chips ITG-3200 too - arrived in Australia today so I will have them tomorrow/Monday
I am including a pressure sensor as well so hopefully we can sense ground level when returning. And a GPS can be added plus ultrasonic sensor (parallax) to do ground sensing.

Here is the link http://forums.parallax.com/forums/default.aspx?f=25&m=436063

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Links to other interesting threads:

· Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
· Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz

mctrivia

no. it is good you point this out. this is something i have been wanting to do but at $80/project I add I want to add only good projects

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Lots of propeller based products in stock at affordable prices.

Timmoore

I assume the 10th is pressure? I noticed the quad thread mentioned the SCP1000, is that the sensor you plan? I have used the hp03 and mapped to altitude and its very senstive when averaged correctly though you have to be careful using it over a long time period since the weather affects the altitude then but if you used the pressure sensor in the short term and gps in the long term it should work.

Cluso99

Is there a problem with the forum??? Lost·2 posts now.

Yes, the 10th is Pressure. I did not count Temperature. GPS and Ultrasonics will add another 4.

The SCP1000 apparently is going obsolete so I will use the BMP085. It is a little less sensitive but cheaper.·The Ultrasonic Sensor from Parallax for ground proximity for·when close to the ground can be added simply, as can the cheapie GPS from Parallax for $25 including inbuilt antenna.

My parts are now in Australia - Gyro, accelerometer, compass, pressure, GPS. I already have props.

The pcb design is well underway. It also has the RC inputs and ESC outputs on the pcb. The prop should do a really great job at this with it's multiple cores.

Tim, you are quite a bit more advanced than we (on the quadcopter thread) are, so your work will be a great advantage to us. Hanno has also done quite a bit of work in this area, and so has Jason Dorie. I am really excited with this project.



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Links to other interesting threads:

· Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
· Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz

Timmoore

@Cluso99, An update: I got hold of a ITG3200 and have a driver that works, I also have a driver for the I2C version of the SCP1000, i haven't integrated them into the IMU code yet. I dont know how far you have got with your board but if you want the drivers and the test code I can post them.

Cluso99

timmoore: Great news. I have not completed the pcb yet - a few other things with higher priority but I should be back on track shortly.

16 prop pins will have 0805 smt resistors for protection. These are intended for up to 8 RC Rx channels and up to 8 Tx (ESC) or servo channels. They are brought out to 2 sets of 8x3 0.1" pin stakes (or holes if not fitted).

All my parts have arrived including the ITG3200's and BMP085 and SCP100-D11. I also have the Parallax GPS module.

I have a new microSD slide socket which locks the card in. However it is a little flimsy so I an unsure if I will use this or the one I use with RamBlade/TriBlade which is a more secure socket. I can probably find the space to put a hole (for a cable tie) on the edge of the pcb just past the uSD card to prevent it from popping out under flight.

I have verified driving the motor esc via the prop - works nicely. I have yet to order all my mechanicals.

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Links to other interesting threads:

· Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
· Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz