MultiWii

edsimmons3

Hi Cleanflight folk I'm getting a big sky-camera-tractor going with the latest cleanflight release and would like to know if it is possible to get PPM sum *output* from a servo pin on my flight controller? I would like this to simplify the connections to my multi-axis gimbal and camera controls. Man...

edsimmons3

Hi Matt,

You may find some success in using a tool like meld (graphical diff & merge tool) to merge your changes from 2.3. Are these changes likely to help others? If so could we start collecting useful things for possible future inclusion? I have a few local versions with edits too...

Ed

edsimmons3

Have you properly shielded the baro from light and wind? Is your altitude hold working and the PID tuned for your quad? GPS hold is 2D position hold and is tuned by the two PIDs PosR and NavR. If the quad is falling when you are trying to use position hold, can you tune just the altitude hold on it'...

edsimmons3

The jerking problem you mention is PID tuning of NavR and PosR. These PIDs control the attitude adjustments made to the craft to navigate (back) to, and hold in the hold position. I found the default settings made regular pulses on the motors on my large quad and have re tuned the PIDs by starting w...

edsimmons3

By the way, have you tried the later verison of multiwii, I think I started out with 2.3 and then chose the release that was current on github a couple of months back. Sorry to be vague but I had much more success with the newer code and the I2C board. I found initially that I was greedy with the op...

edsimmons3

Do you have sufficient ram on your controller for the setup you have chosen? Please could you share your config.h file? Perhaps via pastebin or similar to prevent filling up the forum thread...

Thanks,
Ed

edsimmons3

Uncomment #define USE_MSP_WP then the EZgui etc will be able to communicate mission info to the flight controller.

edsimmons3

I had a look at cleanflight's PID for alt hold. See m for cleanflight vs m I think the discussion surrounding the PID in the other forum thread http://www.multiwii.com/forum/viewtopic.php?f=8&t=6738 is heading in the right direction - I would like to see this improved... I hope to get a chance t...

edsimmons3

How long can parsing 16 bytes take? Checksums can be costly if not implemented really efficiently... I think the nice thing about the complimentary filter working with the integrated distance (calculated only for the current cycle's data) being added to the filter total means we haven't got a runawa...

edsimmons3

I'm surprised you didn't find a short! I would suggest that you got another board at this point... Sorry!

edsimmons3

Looks very cool... If you ever plan to use GPS navigation, heading hold or headfree modes, get that power distribution board as far away as possible from the flight controller. The magnetic fields around the PCB power distribution boards are strong and will mess up magnetometer heading really easily...

edsimmons3

Just out of interest what rate are you sending packets and how long does it take to parse it? Can't you round-robin schedule responding to the packet in smaller steps similar to GPS data so it takes a few iterations of the loop and doesn't wreck the cycle time? The Z accel is already being integrate...

edsimmons3

I have to think about this more, it feels late here and I should sleep really.... but... I think that the input altitude value being improved like this negates the need for the D term complimentary filter and a velocity obtained from thisVal - lastVal could be used. This probably brings the loop tim...

edsimmons3

On the subject of altitude control, have you seen Lidar Lite? I *really* want one of these!

edsimmons3

Why not just post snippets here? I can unofficially integrate things into my own forks on github which I'm hoping can be reviewed and included at some point. I just coded this in the existing uint8_t getEstimatedAltitude() method... static float edAlt = 0.0f; // added for testing uint8_t getEstimate...

edsimmons3

Also, the Z accel varies with the cosine of the pitch/roll. So if you feel particularly fancy, de-tilt your accel value with pitch & roll.

edsimmons3

Hi Matt, I think you're right, the alt.EstAlt is derived only from the baro. I have noticed the altitude reported in the GUI is very noisy (slow sinusoidal movement) but generally quite accurate on a scale of several meters. I think complimentary filtering would be good... The same approach used for...

edsimmons3

Hi Multiwii users, We have a piece of 3M self-adhesive backed Mumetal foil/sheet for screening magnetic fields from power wiring. We have some leftover sections that are approx 10*10cm and are the ideal size for larger quad/hex/octocopters that have a central power distribution board that causes pro...

edsimmons3

Which software are you using? Do you want map rotation in EZgui?

edsimmons3

I had a look... Searching through all the files for LAND_SPEED I found this: #if GPS if (f.LAND_IN_PROGRESS) { //If autoland is in progress then take over and decrease alt slowly AltHoldCorr -= GPS_conf.land_speed; if(abs(AltHoldCorr) > 512) { AltHold += AltHoldCorr/512; AltHoldCorr %= 512; } } #end...

edsimmons3

The PTC fuse is the very reflective thing in the middle of the photo. The two black things either side of it are diodes, the left one has a track that joins the pad to the ground fill of the board, the other end is connected to the 5v on the PTC fuse. The yellow/orange thing on the very far left by ...

edsimmons3

To find out for sure I searched the multiwii code for WAIT_FOR_RTH_ALT. It is only used for RTH in the code: case NAV_STATE_RTH_START: if ((alt_change_flag == REACHED_ALT) || (!GPS_conf.wait_for_rth_alt)) { //Wait until we reach RTH altitude GPS_set_next_wp(&GPS_home[LAT],&GPS_home[LON], &am...

edsimmons3

If your meter is really sensitive on the low ohms range, you can probe round everything that looks like it's connected between 5v and gnd until you find the lowest resistance. I'd guess you'd have settled on a diode that's fairly chunky in comparison to the rest of the small SMT parts. Since it seem...

edsimmons3

You have probably got a short circuit somewhere... Use a multimeter set to measure resistance and check what the reading is when you measure between 5v and gnd. You have probably damaged a reverse polarity protection diode or something that has gone dead-short. You can find which board this is on by...

edsimmons3

I know this thread is old but there's some good info here... Does anyone mind me adding the info from Alex to the wiki? Judging from the forum questions it would help to lay this info out clearly for all to find.

Thanks,
Ed

edsimmons3

If there is a problem in the code that caused this somehow, then I'd like to see if it can be found and fixed... If it is possible to send your craft away *thinking* it is supposed to be following waypoints, it shouldn't be able to leave unless it can actually navigate (but PIDs being set incorrectl...

edsimmons3

James, just to get this back on track...

As kbev pointed out, do you have #define USE_MSP_WP uncommented?

Does RTH work correctly and reliably, even in the wind?

Thanks,
Ed

edsimmons3

Yeah, what's with the lecture seemingly directed at me? I earn my living by programming firmware in C, developing electronics and writing documentation... *I* have read the code, wiki, forum etc. I'd like to know why/how the OP had this happen, that's the point of this thread, surely it shouldn't be...

edsimmons3

Hi, Please make sure you've done the TX setup as per the instructions... Make sure that the stick values all move for as much of the 1000-2000 range as possible. Check this in the GUI, perhaps without batteries connected just to be safe! You may need to adjust the 'throw' of the channels in your TX ...

edsimmons3

What are your stick RC and expo settings? The defaults for these (set by the Multiwii processing GUI) feel really twitchy away from the mid-stick position and i turned mine down quite a bit. Flight was much better.... Once I had the stick rates being kinder, it was much easier to get the feel for tu...

edsimmons3

Surely this is a bug/feature that should be fixed? It violates the rule of least surprise! Enabling a mission with no waypoints loaded shouldn't be possible to prevent this sort of fly away... It's got to be a simple thing to check for, after all, it can tell when a mission is finished, perhaps the ...

edsimmons3

I realise there is little to do with actually navigating in config.h, however, why would it just fly off?

edsimmons3

Hi James, What are you Pos, PosR and NavR PID settings? What is the size of the quad? Does your heading change when you arm your motors? There can be problems with magnetic fields around the high power ESC wiring that cause the compass reading to change when you apply more throttle, this will have i...

edsimmons3

Hi Maxwell,

Would interested parties be able to obtain some samples for trials? Thanks,
Ed

edsimmons3

You only need to adjust the PIDs in Multiwii, the I2C nav board stuff doesn't have any effect in 2.4 multiwii (don't know about previous versions)... Please ensure your heading isn't deviating when you arm the motors and apply some throttle... this will cause circling in pos hold. Check this with pr...

edsimmons3

Hi Multiwii folk, If you need CNC machining of any one-off or small quantity parts please PM me or reply to this post. We have a small CNC mill equipped for cutting sheet materials and 2.5d milling. We are happy to make alterations to existing parts to meet your needs and can work with anything from...

edsimmons3

Hi Solarwater,

Gald you're still about - I guess you're right... the second check seems redundant...

I'll try and get this tested soon and let you know the results. I saw that GPS Home is enabled when I switch off my TX, so that's a good sign

Nothing crazy happens either

Have fun.
Ed

edsimmons3

If your switch is only two positions, you can enable one set of modes on the low position, then set other modes on the high and mid positions.... This way it doesn't matter very much what values the switch gives...

I hope that helps....

Ed

edsimmons3

Er... yeh. Hence asking people to take a look at the github fork which is *clean* code on top of 2.4 multiwii with no other changes. Any takers for testing or review? It;s ready to go, bench tested and I'd be flying now it if it wasn't raining!

edsimmons3

Hi Hamburger, Thanks for the explanation - that makes sense... I have already put the modified code into the github fork I showed in the above post. I will proceed with testing this in flight soon but it has been tested on the bench already and appears to work fine. I made some modifications to the ...

edsimmons3

http://ibin.co/2G3R7NIT9UMV You can hopefully see from my config that when AUX1 is in it's highest position (it is a 3pos switch on my TX) that RTH is activated along with Horizon, Baro and Mag. My aux2 is just a 2 position switch and selects headfree when the channel is in the high position.

edsimmons3

Hi Corrado, You will need to connect some extra channels to your multiwii and set them up for AUX inputs. If you have a standard receiver setup working you should already have AUX1 enabled, AUX2 you can get by choosing one of: #define RCAUXPIN8 //#define RCAUXPIN12 Once you have channels wired up to...

edsimmons3

When the number of satellites used in GPS fix is below 6 some features disable temporarily while the fix isn't good enough. I have been testing this on the bench and I've seen that as long as it arms with a good GPS fix the home location is valid. RTH and poshold modes work all the time they are ena...

edsimmons3

Yeah... I think we covered it briefly.. He's probably got mechanical trims (my friend the other day couldn't arm his quad about 3 times due to accidentally moving the throttle trim...) I have opened an issue on github regarding the default values for pitch&roll Expo and Rate: m hopefully this ca...

edsimmons3

Hi Ronan, No you don't need impedance controlled PCBs, these are normally used for extremely high frequency designs such as radio and high bandwidth digital data. Obviously you need to be careful of the trace widths, try to use a very solid ground plane to aid in heat dissipation. Keep inductive loo...

edsimmons3

Hi MultiWii devs, I have forked MultiWii on GitHub and I hope to gradually collect together all the features that are languishing in various forks/zip files on the forums... How should we go about testing, verifying and merging these useful modifications with the main source code? Isn't it time the ...

edsimmons3

Hi Solarwater, I have just added some changes to the code, now it is possible to compile it without GPS support and without FAILSAFE_RTH enabled. Previously there was a check for GPS fix that was was always included in the code even without a GPS enabled, this caused it to fail. I hope that once tes...

edsimmons3

Hi,

I think now that your throttle might be too low... In the screenshot it shows 977 which is lower than the threshold for failsafe of 985. This will probably stop it from arming.

Set the channel for 1000-2000 (or better yet for safety margin 1005-1995) and you should be ok!

edsimmons3

Hi Solarwater, I took a look at your code and really like the additions you have made. I grabbed a fresh fork of MultiWii 2.4 on github and your files and merged them... The results of this are here: m. I'd be really grateful for any feedback, so far I have bench tested this successfully with the co...

edsimmons3

Is it a bit of a discrepancy that the I2C nav board firmware begins to flash the LED 3x for a 3D fix when there are 5 or more satellites in the GPS fix, whereas the MultiWii firmware does some things only when there are 6 or more?

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