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Sudden APM.1 failure - help !

Started this discussion. Last reply by Simon Jan 23, 2012. 3 Replies

The latest IMU (for now)

Started this discussion. Last reply by Curt Olson Aug 24, 2010. 3 Replies


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Simon replied to Guaifi's discussion The problem IS NOT the 3.3 regulator, it is the dataflash level shifter
"The data lines PG0, PA6, PJ2, PJ1 from the AT2560 link to the A port of the TXB0104 level converter. This is the LOW voltage side. THe output lines from this chip - the HIGH voltage side B port - go to the AT45DB161 dataflash chip which is powered…"
Mar 10, 2014
Simon commented on Jérome Mathey's blog post Front mount brushless gimbal for Discovery like frames
"@Steve - yes, in my opinion that's the wrong way to use those dampers. As it happens I'm just mounting my design to a 450 frame. Looks good so far. Parts 3D printed, uses RC-Timer motor for roll axis and a self-wound motor for pitch…"
Feb 14, 2014
Simon replied to Jean-Philippe's discussion how do I select the optimized wire gauge to connect motors for my Octa V copter ?
"38 inches from motor to main platform - that's one big machine ! As far as your choice of wiring goes I suggest that you read through the attached file. You'll find lots of similar advice around the web - and on this forum. With regard to…"
Jan 3, 2014
Simon replied to Randy's discussion ArduCopter-3.0.1 released!
"@ MHA Re. TBS Discovery geometry - take a look at the Discovery manual. The angles you want (55 deg and 125 deg) are the angles between the centre line and the motor axis to CoT point. Max Levine did an earlier post re the set-up. Hope this…"
Oct 2, 2013
Simon commented on Jani Hirvinen's blog post Adding more features to IOBoard
"LTMNO - so which one is the DHT-U display exactly ?"
Jul 28, 2013
Simon commented on Jani Hirvinen's blog post Adding more features to IOBoard
"Richard, I do like that degrees symbol used by OpenTX, very neat. However the minutes section - 97.8676 - is clearly not correctly displayed. I should have mentioned earlier that the FrSky protocol expects data in the form dddmm.mmmm. I  went a…"
Jul 28, 2013
Simon commented on Jani Hirvinen's blog post Adding more features to IOBoard
"@ LTMNO No, of course the numbers don't 'match' - they're not in the same units are they. Take another look at my post. MAVLINK sends data in degrees.decimal degrees The latest FrSky_Mavlink program will transmit the data as…"
Jul 27, 2013
Simon commented on Jani Hirvinen's blog post Adding more features to IOBoard
"@ LTMNO Please explain why you think that Lat/Lon are incorrect."
Jul 27, 2013

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Gyros for ArduPilot

Posted on January 15, 2009 at 6:53am 7 Comments

I understand the issues about using simple rate gyros with an autopilot - i.e. you can't unless teamed with accelerometers etc - but could one use a head-lock gyro for stabilisation via aileron control ?
Max flight time would be about 10 - 15 mins.


Comment Wall (3 comments)

At 11:58am on February 13, 2010, Mark Whitehorn said…
What kind of problems were you seeing related to use of a 4.7uF cap for C21? The datasheet calls for a low ESR 4.7uF. My Razor 9DOF seems to be working OK on the bench, but perhaps I don't know what problems to look for.
At 4:47pm on February 13, 2010, Simon said…
If it's working then you're fortunate ! With the HMC5843 board (same device/circuit) I found that the 10uF cap - as fitted by Sparkfun - did not allow any data to be collected. Nathan at SF said that this was known to be a recurrent problem but that they had had working units using either the 4.7 uF cap (as recommended by HP) or the 10 uF cap and were unable to replicate the problem.
If you look for info on the web about using the HMC5843 you will see that many other users have reported that these lower value caps just aren't suitable but that increasing it to e.g.100 uF gives a working result. Jordi has had the same problem and uses a 33uF cap in the DIYD mag board.
I was frankly surprised that SF chose to stick with the low value cap for the 9DOF board.
I wondered whether the cause of the problem might be the strength of the local field components but NW UK and Denver are pretty similar.
At 10:16am on February 14, 2010, Mark Whitehorn said…
Thanks for the info. After websurfing for a while, my guess is that the problems are due to high ESR (equivalent series resistance) which depends on both layout and capacitor type. I'd hope the engineers at Honeywell would specify a conservative datasheet value for the capacitance, and that only leaves ESR as a variable.

I'll post a comment if I run into any problems with my 9DOF board.

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