Re: DIY digital compass: electronics experts needed!
 

I've just read back through the thread, and I saw the mention of SDIO. It does apparently work, have a chat to Crashanddie who happened to have a suitable card and it was recognised.

Re: DIY digital compass: electronics experts needed!
 

And while I'm waffling, though slightly OT now, has anyone actually tried forcing the USB chipset to host mode using the same trick that was necessary for the N800 and N810 (if you used a gender changer as you didn't want to buy an extra usb cable with the right wire crossed over in it)?

Re: DIY digital compass: electronics experts needed!
 

One of the things I'm working on involves adding a magnetometer (HMC5843 - http://talk.maemo.org/showthread.php...739#post450739) to my stack with a Venus 10Hz GPS (with WAAS and AGPS!), reading J1850 from my harley, my radar detector. I'm also adding baro and temp (and maybe humidity if I can find the right sensor).

The HMC is more than sensitive enough to give a heading reading - I was surprised. It is I2C so just needs to be turned into serial for bluetooth.

Re: DIY digital compass: electronics experts needed!
 

Good find, apparently it does spit out the compass reading along with the barometric data in a proprietary sentence.

http://www.gpspassion.com/forumsen/t...OPIC_ID=117303

Re: DIY digital compass: electronics experts needed!
 

Looks like there's another product in the category of GPS logger + compass + bluetooth: the MN500 from "Themap", a Korean company. Can't find any pricing info yet though, not even on their home page... the product was only recently launched.

http://www.ceatec.com/2009/en/news/e...press_id=00041

specs - Touch_Panel, 3.5"Transflective LCD, Bluetooth, Compass, Altimetric Barometer, 2.4GHz Bike_Sensor(ANT+), CPU ARM9_2442 @ 400 Mhz - you could probably run Linux on this thing, if it's not running Linux already.

I suspect again though it will be rather pricey.

edit: added specs link

Re: DIY digital compass: electronics experts needed!
 

Yeah, if we're going to go that large and pricey it would make more sense to just buy one of the Android devices which comes with GPS + compass and do VR work on there.

That Wintec device isn't available in the UK afaict, so it looks like it will unfortunately be a case of doing some soldering and making up a BT link for the 3-axis i2c accelerometer *grumble*.

Re: DIY digital compass: electronics experts needed!
 

Re: DIY digital compass: electronics experts needed!
 

I've been lurking following the progress of this thread. I have a question. What height (thickness) of chip can the microSD card slot accommodate? Would it be possible to custom fab a magnetometer microSDIO card. The 3 axis magnetometer chip from Honeywell are a bit thicker (1.3mm) than the official microSD card spec (1mm), but they are substantially smaller in the other dimensions (3x3mm vs 11x15mm) so there should be ample real estate for whatever other electronics (i.e. flexPCB). Just wondering!

Re: DIY digital compass: electronics experts needed!
 

I don't think it would fit on an SD card without sticking out (at least on the 900). You might be able to do something via bluetooth (or even flash an IR LED at the camera).

I don't think the Honeywells do SPI (which would make it easy), but do I2C - I have the HMC5843 talking to various Atmel chips (the new attiny45 in tssop might fit in the uSD slot though). It could go via bluetooth as well though it would probably be a bit big.

Re: DIY digital compass: electronics experts needed!
 

I wanted to ask... i thought the N900 does have a digital compass actually? When i use Ovi Maps and the A-GPS, and set a route and drive by car... the map is turning by itself as i drive, targeting always north. For ex. when i turn right, the map turns with me. I though that can be done only with a digital compass? Or am i wrong?