PIPO ISU - stabilization board

Post by **erazz** » Sat Mar 10, 2012 9:18 pm

Long dormant project of mine that I finally got rolling.

The PIPO ISU is a small (1.5"x1.1") board that includes a 3 axis gyro, 3 axis accelerometer and 3 axis magnetomer.
The board itself is powered by an Atmel 328P chip that is arduino compatible.

It accepts up to 8 inputs from any rx and can output up to 8 servo/esc channels.
(I'm working on an extension that will take S-Bus or PXX data and output 16 channels but that's a different story)

Here's a pic:

This project has been on hold for almost a year because of serious hurdels in programming.
I'm happy to report that thise have been overcome! It now works very well as can be seen by the video:

http://www.youtube.com/watch?v=qD54hP5NwY4

BTW, the crash at the end is my Flysky receiver (that has been through a lot) giving up the ghost. I guess I have to make everything FrSky again

Project site:
http://code.google.com/p/pipo/

Store:
http://www.eraviv.com/store/page2.html

Price for forum members is: $60.
S&H to USA is $7.
S&H to Europe is $18.

PM me to order.

Post by **cre8tiveleo** » Sat Mar 10, 2012 9:49 pm

Nochmal! FLip.. nice!

I expect my Quad to do that a few times before I know how to fly it.

Cool beans!

Post by **cre8tiveleo** » Sat Mar 10, 2012 9:55 pm

Omg... the videos on the 'shop' site.. the guys laugh at the end, and during the wiicopter throw... yikes.... scary...

kaos · Post by **kaos** » Sun Mar 11, 2012 12:31 am

Nice flip. Looks like the fish I just landed.

This 3 axis.. Gizmo can really help my VTOL project.
Keep it up erazz. Let us informed.
Thread subscribed!

Post by **erazz** » Sun Mar 11, 2012 2:26 am

I think I know what went wrong. I assumed it was the receiver. A unit which was subjected to heat, cold, and variouus electronic experiments in trying to reprogram it. (no, it didn't work)
I naturally assumed that it was the peice to fault.

Not the case.

The real reason was a shorted resistor in the Frsky telemetry mod. See, it kept on working. Especially because I don't normally use the "ELE" switch. However, I accidentally bumped the switch before the video. The short put too much stress on the MCU and weird things started happening.

I have now replaced the resistor and all is well in PIPO/ER9x land

Post by **GrootWitbaas** » Sun Mar 11, 2012 7:14 am

You should really be looking into stm32 - it's 2012 after all ....

Post by **erazz** » Sun Mar 11, 2012 1:44 pm

Why?
Atmels are easy and ubiquitous. They work on 5V so I don't need a level converter. Small and low power draw....

As far as computational HP believe it or not it is more than adaquate!
For this project the small size and 5v trumped computer power. I'm actually glad I went with the Atmel.

Hasse.69 · Post by **Hasse.69** » Sun Mar 11, 2012 8:38 pm

How much????

Best regards , Hasse.

Post by **GrootWitbaas** » Sun Mar 11, 2012 9:20 pm

erazz wrote:Why?
Atmels are easy and ubiquitous. They work on 5V so I don't need a level converter. Small and low power draw....

As far as computational HP believe it or not it is more than adaquate!
For this project the small size and 5v trumped computer power. I'm actually glad I went with the Atmel.

Well for a few reasons, but mainly because it works on 3,3v (I even have one working on 2,8v) so I can use it in a single cell application (micro quid)
More memory for expatiation and has the possibility of on board usb programming. TC has even ported MW to it already. I have a pipo, FF flight and got some AfroFlight32 boards from TC (have build one complete and working on the second.)
Yes I know it is completely new tool chain and all from atmel, but TBH I'd love to see a eepe like fronted for the PC and a different approach for the code. MWwinGUI .net looks cool and all but ....if you revive this dormant project, don't you want to consider moving to newer Technology. STM dev boards are cheap, STM32F103 also.

Post by **erazz** » Sun Mar 11, 2012 9:43 pm

OK.... But how do I get it to work with 5V receivers?

Though, I might do a supersmall board for quads with a Cyprus chip for quads.... Hmmmm.... Got me thinking....

Post by **GrootWitbaas** » Sun Mar 11, 2012 9:55 pm

A but I don't use 5v Rx for this

here is the link to ppm sum receivers and it's happy with only 3 volts

Because I don't use LiPo but only Life and A123 (personal pref) I have to be careful on the limits on the lower end, and that is why I was testing a low down as 2,8v.

I only posted the above to try and get you interested in the stm32F103 because I do not have the time to do this. TC did a clone of the FF with his Afro32 but I personally would like to see a design where the cp2012 is eliminated and the STM32 native USB is used. I see this as the 2012 flight controllers. I have a design halfway made, but for the coding part I am a complete noob.

Post by **jhsa** » Sun Mar 11, 2012 10:41 pm

Don't tell me that you mod the frsky receivers to work on 3.3V

Post by **Kilrah** » Sun Mar 11, 2012 10:48 pm

All it takes is a piece of wire, no?

Post by **GrootWitbaas** » Sun Mar 11, 2012 10:49 pm

actually never looked if I can strip down the Frsky ....did strip down a 6ch stock Rx, but that was running on 5v for a slightly bigger quad.

/me thinks it's time to open the FrSky and have a peak inside

Post by **Kilrah** » Sun Mar 11, 2012 10:54 pm

I haven't done measurements, but (at least on a D8RII) everything's behind a nice little Vreg

Post by **jhsa** » Sun Mar 11, 2012 11:14 pm

The frsky receivers (at least some) are reported working under 3V before they die

Post by **erazz** » Sun Mar 11, 2012 11:29 pm

GrootWitbaas wrote:A but I don't use 5v Rx for this here is the link to ppm sum receivers and it's happy with only 3 volts Because I don't use LiPo but only Life and A123 (personal pref) I have to be careful on the limits on the lower end, and that is why I was testing a low down as 2,8v.

I only posted the above to try and get you interested in the stm32F103 because I do not have the time to do this. TC did a clone of the FF with his Afro32 but I personally would like to see a design where the cp2012 is eliminated and the STM32 native USB is used. I see this as the 2012 flight controllers. I have a design halfway made, but for the coding part I am a complete noob.

And you absolutely did!
I'm thinking about a low cost STM powered board with only the Gyro and designed to work on 3.3v with CPPM/SBus/PXX.

Looks like I'll fire up the design software tonight

Post by **erazz** » Sat Mar 24, 2012 4:11 pm

Update:

I really cracked it!
Autolevel works wonderfully. Loop duration is down to 6msec. That's 160Hz. Plenty fast for quad flight. We have some nasty winds here and it handles them beautifully. I'll get a video later today or early tomorrow.

Anyway, the pros the software has:
1) Fast! Loop times are plenty fast for anything you can throw at it.
2) Synced pulse. All output channels are initiated at the same time. This is rather uncommen and has great benefits for control.
3) Autolevel can be set to different levels. There's no "stable" and "acro" modes. Just one mode that you can vary the stability to whatever value you want.

I am currently working on a number of fetures:
1) CPPM/PXX/SBUS input.
2) 16 channels output. (the neat thing about the way the channels are sent is that having more channels is easy and does not degrade performance.
3) Flexible mixer. I finally know how to do this right!

I'm thinking of ditching the compass. I don't think that it's needed to get reliable yaw hold. No doubt that with extreme manuvers it does come in handy but overall I think we can have sufficient functionality for the "ISU" paradigm without it. It will also allow me to substantially reduce the price of the unit and increase performance to boot!

As for stock. I have all the parts in so I can start sending out units to those who have asked for it.

Post by **Rob Thomson** » Sat Mar 24, 2012 4:38 pm

Nice! Now all I need is a quad copter

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Post by **cre8tiveleo** » Sat Mar 24, 2012 4:52 pm

Quad?!

I just built mine yesterday

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I am here: http://tapatalk.com/map.php?ao4j5k

Post by **jhsa** » Sat Mar 24, 2012 5:00 pm

that's a nice looking quad..

Post by **erazz** » Sat Mar 24, 2012 7:11 pm

Where did you get the frame from?

HK's is not up yet...
http://www.youtube.com/watch?v=BPSTlirQHi0

Post by **erazz** » Sat Mar 24, 2012 7:12 pm

Oh, and btw.

Unlike other boards, this will have an er9x style mixer so you could stabilize your airplane/heli/quad/boat/spaceship.

Post by **Rob Thomson** » Sat Mar 24, 2012 7:26 pm

So... Technically I could plug it in a plane? And it will keep it nice and level?

Rob

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Post by **erazz** » Sat Mar 24, 2012 7:38 pm

Yup. That's the idea

I'm rapidly approaching the point where I'll put it on a heliu and use it as a flybarless unit. Would be nice, a flybarless unit which would keep your heli nice and level.

I'm quickly developing a hatered of the HMC5883L compass. It's slow, expensive, hard to get right and doesn't add any value to the unit. Next units will most definitely NOT include it!

Post by **Rob Thomson** » Sat Mar 24, 2012 7:58 pm

What sort of cost will the unit be?

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Post by **cre8tiveleo** » Sat Mar 24, 2012 8:25 pm

erazz wrote:Where did you get the frame from?

HK's is not up yet...

$15 ebay. Free shipping. Hk is slow

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I am here: http://tapatalk.com/map.php?oo1y4c

Post by **GrootWitbaas** » Sat Mar 24, 2012 8:55 pm

Lucky my pipo does not have one(compass), it was ordered way back while you waited on the stock....I were planing to add it but now i won't

If it works on heli it will go into my 450 A109 Scale.

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Post by **erazz** » Sat Mar 24, 2012 10:10 pm

Just test flew my non-compassed PIPO. Works splendidly. Still need to verify that everything will work properly and then I'll post the code. I expect that to be tomorrow as I'm working furiously on it.

Hi Rob,
I'm not saying anything about the price yet. It will be lower than the current price. I'm currently trying different components to reduce the price. I am totally stoked at the progress but I know from the past that until I have something working properly I won't sell it. Just not worth the pain.

Post by **erazz** » Sun Mar 25, 2012 12:04 am

Groot, this is for you: Attached is a working version sans the compass.

I am much more pleased with this. Speed is significantly faster (200Hz instead of 160Hz) and code is smaller (35% instead of 45%)
Same exact functionality and you don't need to calibrate the compass!

Wicked. PIPO v3 is already on it's way to the board maker. Size is doen to 1.5" x 0.95". Tiny!

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