[ggrif]

A pic of the BangGood Revo, just for reference. I haven't flown it yet but several guys at RCG have them and are flying without issues, using RaceFlight FW.

[Bob13011]

Hi
Received yesterday Revo and a GPS Ublox M8N from Banggood.
Set up on an old FPV quad with LibrePilot.
Tests ok. Everything works fine. End flight test done at night with attitude, rattitude, altitude hold and GPS Assist
I had a good night. Thanks!

[Zrisst]

Hi
Received yesterday Revo and a GPS Ublox M8N from Banggood.
Set up on an old FPV quad with LibrePilot.
Tests ok. Everything works fine. End flight test done at night with attitude, rattitude, altitude hold and GPS Assist
I had a good night. Thanks!

That's the first kit I got. Except for the mag issue posted in other treads it works fine.

[hburke]

Thanks for the info Cliff. I dont know how to test the baro like you did, but I bet a million dollars this is why my Revo clones didnt work. I didn't get mine from either of those sources though. I think I found mine on Amazon or ebay. How do i go about testing the baro like that? what software is it?

And the trianglequads thing is not fake guys. I have 2 of them. I cant find the picture i took, but i posted it somewhere on RCG. I got them a while back from the makers and they are just like the OP Nano. i have one of the real ones that came from the OP store. I keep seeing people saying they arent real or it's a scam, but the guys that made them are in the USA and good guys. I would have said something about them earlier but they asked me not to say anything to anyone because they were not going to sell them. Scott gave me mine, I just had to pay shipping and actually i only asked for one and he sent me 2. i guess i told him my brother also was into drone racing so he sent 2 of them. i honestly cant tell any difference between my nano and their board and i used our GCS to set it up. Which works great btw :-)

I would highly recommend it over a Revo clone, both revo clones i bought were a bust. I stayed in lines for hours so to speak for the OP Nano and i loved it when i got it, but now i cant get anymore and triangle quads fell out of the sky in my lap like an angel :-D  .. the board is obviously high quality. it looks nothing like the cheap cc3d or revo clones i have had. i bought 2 more and i'm ordering another 2 today or tomorrow because my brother will not stop asking me for one and our friend that flies with us wants one. i for one am glad we have a source now.

[TheOtherCliff]

We had a User in german Forum who had the same problems with his revo clone altitude oscilation about 10m while standing on the table inside the house, He fixed the problem by soldering a Filter capacitor direktly to Vccin at the baro did you try something like that?

One of the devs has gone so far as to replace the baro, the baro power filter capacitor (several values), and the regulator on a Sparky2 clone, and the scope still shows a large amount of noise.  There are still some things he is checking in to.

[TheOtherCliff]

A pic of the BangGood Revo, just for reference. I haven't flown it yet but several guys at RCG have them and are flying without issues, using RaceFlight FW.

Using RaceFlight FW sounds like they are not using the baro.  For LP firmware, the baro is only used in altitude hold/vario throttle modes or in GPS flight modes.  Do racers use baro at all?

[ggrif]

Good point. Probably not.

[Brian]

I solved the issue, at least for the Sparky 2 clones.  The Sparky 2 schematic that I have specs an LP2992 voltage regulator, but my board has a MIC5219.  The different regulator isn't a problem, in fact is supports higher current, but it is not necessarily a drop-in replacement for the LP2992.  For example, the MIC5219 suggests a 470pF capacitor for a bypass capacitor, and the LP2992 specifies 10nF, which is what is on the Sparky 2 schematics.

My guess is that the cloners replaced the voltage regulator without changing the capacitor values and installed a 10nF capacitor, which is 20 times higher than recommended.  I believe this is causing the voltage regulator to not regulate properly and was causing the (relatively) low frequency noise on the Vcc line, and was causing the fluctuations in the baro readings.

I completely removed the capacitor and now the baro is stable to within about a meter, which is much better.  The MIC5219 will work without a bypass capacitor, but a 470pF capacitor could help lower the noise even more.

The bypass capacitor is the small capacitor directly in front of the regulator.

I somehow fried my Revo clone, so I can't test if that has the same problem, but it is probably worth investigating.

[TheOtherCliff]

That's great news!  Brian put a lot of work into debugging this for us.

[JaeMelo]

I solved the issue, at least for the Sparky 2 clones.  The Sparky 2 schematic that I have specs an LP2992 voltage regulator, but my board has a MIC5219.  The different regulator isn't a problem, in fact is supports higher current, but it is not necessarily a drop-in replacement for the LP2992.  For example, the MIC5219 suggests a 470pF capacitor for a bypass capacitor, and the LP2992 specifies 10nF, which is what is on the Sparky 2 schematics.

My guess is that the cloners replaced the voltage regulator without changing the capacitor values and installed a 10nF capacitor, which is 20 times higher than recommended.  I believe this is causing the voltage regulator to not regulate properly and was causing the (relatively) low frequency noise on the Vcc line, and was causing the fluctuations in the baro readings.

I completely removed the capacitor and now the baro is stable to within about a meter, which is much better.  The MIC5219 will work without a bypass capacitor, but a 470pF capacitor could help lower the noise even more.

The bypass capacitor is the small capacitor directly in front of the regulator.

I somehow fried my Revo clone, so I can't test if that has the same problem, but it is probably worth investigating.

This maybe the case for the Sparky2 FC but I can tell you for sure this is not the case for the Revo. I own the original Revo that comes in those cute little OP boxes, a scratch built revo using an OSHPark PCB with components from Digikey/Sparkfun in addition to the two types of cloned revos available on the market. There are two different kinds of cloned revos which are floating around. One which follows the original OP gerber/schematics and components and another which doesn't at all. The one that doesn't follow the original OP gerber works perfectly fine like my real revo but looks extremely cheap and has german colored header pins. The other clone that actually follows the original OP gerber/schematics and components has given me mixed results between the 5x boads of this particular kind that I've owned in total. Some of them are good with stable baro readings while some of them are total garbage. The point is both of the different types of clones use the exact same 400mA LDO regulators and have 10uF caps on the baros VCC side. So that rules out a difference in regulators/caps for the revo clones. The only thing I can think of are the caps are either junk on some units or the baro is the culprit. I won't know for sure until I dig deeper. I will swap components around tonight between the crappy clone and the good working one and will respond with my findings. I'll also post pics of these revos SBS so you can see the differences.

In the picture below from left to right is the:
Hand Built Revo(OSHPark) => Clone1(FollowsOPGerber) => Clone2(ModifiedOPGerber)


In the picture below shows the two clones SBS... Noticed the difference in components and their placement.


And this pic just shows my two builds. The hex has the real OP Revolution under the hood that is missing in the first pic while the quad has one of the Clone1 Revos shown in the first picture, but with perfectly stable bro readings.


These are the boards that I am using to scratch build the revo in my first pic which follow the original OP Gerber.

[ggrif]

Excellent information/work! Thanks!
I'm looking forward to following your quest.

[Brian]

I just received one of the "modified" clone Revos, and your assessment is similar to my experience.  The clone seems to work fine, but it does have a different layout.

The only problem that I've found so far is that the power LED is closer to the mounting hole, so it interferes with standard (1/4" 4/40) nylon standoffs.  You can clearly see the difference in the picture above.

[TheOtherCliff]

...
The point is both of the different types of clones use the exact same 400mA LDO regulators and have 10uF caps on the baros VCC side. So that rules out a difference in regulators/caps for the revo clones.

It's my understanding that the problem is with the Bypass cap, not the Vout cap.  It oscillates if the value is too large.

[perchybits]

Just thought i would chime in and add my experience to the discussion. I purchased the Amazon Revolution clone with the case and the yellow red black upright pins. Quality of the part looked good to the naked eye. Board was installed with a Ublox M8n GPS hooked to th eflexi port. After hours of messing with it I can confirm that mine not only has the bad barometer which makes altitude hold useless, and the Main port is not functioning at all. Board also is unusable in gps assist mode. It is impossible to calibrate in ins13 mode.  even with 20 satellites locked it dances and horizon falls and dips by 20-30%! I managed to get it up in the air in ins13 in rate mode and put the hexcopter into gps assist and altitude hold and it was hilarious to watch, the poor thing looked like it had cerebral palsy. It was shaking and dancing all over the place. So I removed all gps flight modes and turned basic mode back on.

Still... in Basic complementary mode it is super solid and flys like a champ! it is very smooth and fun to fly in Rattitude and rate settings.

i didn't have problems with the onboard mag. i t seemed to work fine. it would go to orange on full throttle but hold green most of the time.

[JaeMelo]

It's my understanding that the problem is with the Bypass cap, not the Vout cap.  It oscillates if the value is too large.

Can you identify this cap you speak of in the schematic below?
Hi-Res Image

Just thought i would chime in and add my experience to the discussion. I purchased the Amazon Revolution clone with the case and the yellow red black upright pins. Quality of the part looked good to the naked eye. Board was installed with a Ublox M8n GPS hooked to th eflexi port. After hours of messing with it I can confirm that mine not only has the bad barometer which makes altitude hold useless, and the Main port is not functioning at all. Board also is unusable in gps assist mode. It is impossible to calibrate in ins13 mode.  even with 20 satellites locked it dances and horizon falls and dips by 20-30%! I managed to get it up in the air in ins13 in rate mode and put the hexcopter into gps assist and altitude hold and it was hilarious to watch, the poor thing looked like it had cerebral palsy. It was shaking and dancing all over the place. So I removed all gps flight modes and turned basic mode back on.

Still... in Basic complementary mode it is super solid and flys like a champ! it is very smooth and fun to fly in Rattitude and rate settings.

i didn't have problems with the onboard mag. i t seemed to work fine. it would go to orange on full throttle but hold green most of the time.

Nothing about that board is of quality not even from the naked eye.
In addition the behavior you mentioned is normal when you try flying with mag interference in any GPS mode. It happens with the real Revo's, Naze32's, sparky2 boards ect. The only way around that is to either build your multi rotor to be interference friendly around the FC or, to use a gps with a built in mag and configure the fc utilize the external mag instead. The gps must also be positioned as far away from the interference as possible on a post. If your mag turns anything but green you have an interference issue especially during throttle actuation.