UMX Mig-15 DF Mod Thread - Page 4 - RC Groups
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Jul 11, 2012, 09:07 PM
Way to many airplanes!
Originally Posted by NitroCharged
Here's my initial findings of the board:

Firstly, I have said it many times and been flamed for it over in the other threads - there is no magical stabilisation system running in these things! There is simply a nice 3 axis gyro running in them(X,Y,Z)

It's using the Invensense ITG3205 3 axis gyro chip everyone else is using in everything (the IC on my board was manufactured in Dec 2010). It has an external clock for stability and it's being controlled by a standard controller/processor LPC1114/302. It is simply programmed as a master to receive the gyro inputs and mix them into the servo signals via IC method with the gains set to suit the model. The techheads in the multi rotor forum could really come in handy here!

The fact that the gyro is placed in standby mode until the throttle signal is raised shows that the processor can be programmed to turn the gyro off and on(standby) and since there are 6 channels on the board.... - you do the maths...

STBY_XG Put gyro X in standby mode (1=standby, 0=normal)
STBY_YG Put gyro Y in standby mode (1=standby, 0=normal)
STBY_ZG Put gyro Z in standby mode (1=standby, 0=normal)

If the processor loses it's connection with the gyro, the board will not function.

The voltage regulator is an LM29401 5.0 variable voltage regulator tied to 4.3V output.

The ESC FET's are 4606 FET's rated at max 30V and 6A.

Now, since I can't put the gyro into standby manually, I'll drop in a stripped down 6100 and CC Phoenix 10A and see how she flies without the AS3X in it.

Truly love all the specifications...

Two things though:
- It was obvious that we could turn on the gyro already, but what do you mean by doing it on each channel? I probably misinterpret you again, but yes, the receiver is 6 channel, but you need at least one for the throttle, which leave only 2 for whatever you would want to switch. (again, sorry, if I misread your information). But at the processor level, they can surely do whatever they please...

- This bring the second thing: Nobody said the magic was in the MEM gyro ever. We always said it was in the programming. And that's the reason I like your IC specifications so much. This is a kickass microcontroller on this receiver. Wooooweeeeee! Have you look at the specifications for it? That's were the magic is happening. I was wondering how they could add expo so easily onboard, but with such a monster, there's truly a LOT they can do. The fact that they could add a nice MEM gyro and such a kickass controller on our receiver without increasing the price is fantastic!!!

Here's the specs for the controller:
The NXP (founded by Philips) LPC1114/302 is an ARM 32-bit Cortex-M0 Microcontroller with MPU, CPU clock up to 50MHz, 32KByte on-chip Flash ROM with In-System Programming (ISP) and In-Application Programming (IAP) via 12KByte On-Chip Bootloader, 8KByte SRAM, lower power variant supporting the Power Profile SW API. Nested Vectored Interrupt Controller, up to 2 SSP controllers, UART with full Modem Interface and RS485 Support, Fast Mode I2C-Bus, 4 Timers with 4 capture channels and 13 output channels, Watchdog (WDT), Sytem tick timer, 10-bit ADC with 8 channels, Power Management Unit (PMU), Brownout detection, 12MHz internal RC oscillator, and Serial Wire Debug.

Note: For people who have never programmed a microcontroller, don't be fooled by the low clock (50Mhz) since that's pretty fast, and standard in low power uC... Same thing goes for the 32K Rom, 12K bootloader, 8K SRAM. This is HUGE in the uC world!!! Now, I'm only dreaming that one day, we could hack this thing! It's probably only half used!
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Jul 11, 2012, 09:25 PM
Team30 Micro EDF
NitroCharged's Avatar
The NXP site has the developer kit for download.

I don't mean anything by each channel - I simply pasted the state required to place each gyro into standby, showing that it can be done easily. So code the LPC so when it gets a high state from one of the spare channels, like CH5, it places the gyro into standby and visa versa.

On another note - the CC Phoenix 10A ESC runs the fan faster!
Last edited by NitroCharged; Jul 11, 2012 at 09:31 PM.
Jul 12, 2012, 04:13 AM
Team30 Micro EDF
NitroCharged's Avatar
I got into the board/ESC swap out. I now have a stripped down 6100 installed. The last time this one saw flight was when it was mounted in my Micro Skyray!.. Wow! that was a long time ago!

The ESC is a CC Phoenix 10A set for 2S to start with. Once the Comparison video has been made I'll bump it up to 3S.

Voltage regulator is a 3.3V 1117 set to 4.2V. (Shown exposed here for the photo)

Jul 12, 2012, 06:28 AM
Registered User
J-ACE's Avatar
Man you do nice work Nitro
Jul 12, 2012, 07:02 AM
Way to many airplanes!
Agreed, nice work Nitro. You even kept the front wheel (would not have bother with that myself). Very sweet installation! Regulator is for the servos? Or because the C.C. doesn't have a bec? Wondering if anybody tried those servos on 5Volts...
Jul 19, 2012, 06:31 PM
Team30 Micro EDF
NitroCharged's Avatar
Thanks guys. Since the VR on the AS3X board was running at 4.3V, I thought I better do the same so nothing runs hot. I tapped the ESC's BEC 5V and dropped it.

I was having a quick look over the AS3X board last night, and for those with a great eye and steady hand, I think you could circumvent the gyro by tapping the servo signals straight out of the rxer chip. I was looking to see where the throttle pin was so it would be easier to hook an external ESC up for 3S and then clicked on 'why stop there?'

I'll get out the probes and have a real look tonight.

Once these programmers come out - I think it will be easier to program it(gyro) to turn off and on.
Jul 21, 2012, 11:41 AM
QuAd FaNaTiC
Razors edge 29's Avatar
CC 10am esc runs fsn faster does it?

Wonder it same on GP sabre?
Jul 21, 2012, 07:18 PM
Team30 Micro EDF
NitroCharged's Avatar
Not a bad call Razor as I didn't notice extra thrust yesterday in the Sabre but on the bench I had a good 10g more static through the CC ESC....??

I might hook one up in the model and find out what's going on.

meanwhile - I'm just about to head out for the 3S tests.
Jul 22, 2012, 02:33 AM
Registered User
How about something to protect the nose? Is it still in the works?
Jul 22, 2012, 02:37 AM
Team30 Micro EDF
NitroCharged's Avatar
Most certainly is. Still waiting for the plastic to arrive.
Jul 22, 2012, 05:36 AM
Registered User
My nose is really messed up. I'm still looking for some kind of foil to reinforce it. So far only a thin layer of CA is holding it together.
Jul 23, 2012, 06:00 AM
Team30 Micro EDF
NitroCharged's Avatar
OK - I did seven WOT passes on 3S using a 180mah Hyperion 25C lipo.

Doppler results were: 53.4, 49.3, 50.9, 49.8, 50.7, 48.8 and 50.5mph giving an average of 50.4mph.
Jul 27, 2012, 07:40 AM
Registered User
After taking heavy damage to the nose, I decided enough is enough. Picked up a plastic salt dispenser($1), cut a hole in the lid, fits perfectly. Will test it tomorrow(CRASH TEST). Will use paint if it doesn't affect the flight much. Some epoxy should keep it in place.
The nose is definitely the weak spot.

Any thoughts guys?

Weight? Not much.
Resistance? hmm....may be...Will know tomorrow.
Jul 27, 2012, 06:41 PM
Team30 Micro EDF
NitroCharged's Avatar
Sweet! Weight and resistance will be negligible. Let us know how yours goes.

I just put my first test bra on my Mig last night. The shrink plastic I got fogs when heated so I ordered some more yesterday(and a little smaller too as the first lot was too big). For now I am keeping it in place with a little 2 sided tape on the bottom.
Jul 30, 2012, 01:15 AM
Registered User
Originally Posted by NitroCharged
Sweet! Weight and resistance will be negligible. Let us know how yours goes.

I just put my first test bra on my Mig last night. The shrink plastic I got fogs when heated so I ordered some more yesterday(and a little smaller too as the first lot was too big). For now I am keeping it in place with a little 2 sided tape on the bottom.
Went pretty well for the first flight. No impact on the flight at all.
Second flight- was flying ok, then as I went into a loop, at the bottom of the loop the elevator stopped responding(just like the first time it crashed). This time the entire nose cone broke off behind the plastic mod. Not happy.

Looks like couple other guys had similar failure:

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