FLEA - Specs and Experiences... - Page 3 - RC Groups
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Feb 16, 2009, 06:12 PM
Registered User
Quote:
Originally Posted by mayday1
Funny everyone is interested in the flea all of a sudden. I was thinking
of proto-typing a flea like device, so ordered a couple of atmega88P, the
avrisp,
and half a dozen of P/N channel FETs from digikey, I ordered them in
DIP format not to build the real thing, but so that I can make a breadboard
version (based on an old towerpro 15A ESC).

My idea is to prototype two versions. A version like the flea that takes
the brushed motor output and simply convert to brushless. A 2nd version
is a normal brushless ESC with a twist. There'll be a trimmer so that
instead of 1mS pulse is minimum throttle 2mS is maximum throttle, the
throttle position can be trimmed. This is for mating with a head-holding
gyro so that when I use a gyro in rate mode, I can trim the throttle
so that the tail doesn't drift in rate mode (analogous to adjusting the
tail linkage/servo position in a variable pitch tail). I believe by doing so,
there is a much better chance to get the head-holding gyro to do its
thing with a motorised tail.

I've been thinking about the motor starting firmware, and have read some
of the application notes from ATMEL about how to get a motor started
and detecting zero-crossing, but it is very complicated. Sounds like
the flea's firmware is available, that will save a lot of time and frustration.

Well, I haven't flown a heli or a plane in almost two weeks, but I
did get a proto-type flea working just a few minutes ago. It is a proto-type
on a bread-board. I used a ATmega88P as the controller, and
three Si4511 FETs. It took me a couple of afternoons
to wire up the proto, and about a week to write and debug the ESC firmware.
The firmware is based on quax's work, but is completely written
in C. The actual motor commutation
code is probably different from quax's since I used the starting algorithm in
ATMEL's appnote "AVR172: Sensorless Commutation of Brushles DC Motor
using ATmega32M1 and ATAVRMC320". I used the same timer/interrupt
idea to detect PPM signal and calculate motor timing as in quax's code.

I've run it on one-cell, it starts a eflite park 370 (4100kV) quite reliably,
but I haven't dared to run it full throttle (worrying that it'll over-current
the little transistors since I'm not doing any current-sense or over-current
protection).

I tried a couple of outrunners (Scorpion HK2221-8 (3600kV) and 3008-32
(1000kV)), neither motor starts but I think I was giving it too little start
power since I'm using 1 cell. I'd love to try it on the hextronix 2g as well as all the
other <10g motors intended for a 4G3 heli. Once I get the motor
start firmware reliable, I'll add the trimmer as given in my previous note
and fab a real board to try it on on my 4G3.
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Feb 16, 2009, 08:20 PM
VE7FM
TheSteve's Avatar
Wow, great work. A nice motor to experiment with would be one of the Losi 10250 kv motors. Startup is always the biggest challenge.
Which compiler are you using, the Atmel code where I work is all in C, compiled with CodeVisionAVR.
Feb 16, 2009, 09:16 PM
Registered User
Quote:
Originally Posted by TheSteve
Wow, great work. A nice motor to experiment with would be one of the Losi 10250 kv motors. Startup is always the biggest challenge.
Which compiler are you using, the Atmel code where I work is all in C, compiled with CodeVisionAVR.
I'm using winAVR's gcc compiler.

I tried full-throttle and it didn't work. Soon as it is near full throttle, the
motor slowed down instead of speeding up. On full throttle I turn off
the PWM and let it run 100% duty cycle, don't know if that is the problem,
or that at 8MHz internal clock, my C program isn't fast enough to do the
commutation. I'll debug tonight. But it is a pain to run full throttle
since I drain down these tiny batteries very quickly. It could also be
the battery voltage sagging too much since the park370 motor is a lot
bigger than what this is for (but it is the smallest motor I have).
Feb 17, 2009, 04:02 AM
Registered User
Flea works fine for tail + 2g outrunner motor
from wowhobbies.

but still, there are multiple versions of the FLEA module.

Speed info would be great thaugh
Dark
Feb 17, 2009, 05:57 AM
Registered User
quax's Avatar
Quote:
Originally Posted by mayday1
...
I tried full-throttle and it didn't work. Soon as it is near full throttle, the
motor slowed down instead of speeding up. On full throttle I turn off
the PWM and let it run 100% duty cycle, don't know if that is the problem,
or that at 8MHz internal clock, my C program isn't fast enough to do the
commutation. I'll debug tonight.
...
If you finally can't solve the full-throttle problem, I offer you to help finding it out.

cul
quax
Feb 17, 2009, 02:32 PM
Registered User
Quote:
Originally Posted by quax
If you finally can't solve the full-throttle problem, I offer you to help finding it out.

cul
quax
thanks quax!

I still haven't figured out the full-throttle problem. It seems like at high rpm,
my detection of zero-crossing fails (I determined this by turning on
a LED right before doing zero-crossing detection, and turn it off after
detecting zero crossing, and when the motor suddenly dies, the LED
is always on). This RPM is quite low (about 6000 electrical rpm), so
I don't think the C-code should have a problem unless I'm running the
core clock much lower than 8MHz. I'm using the internal 8MHz clock
from the fuse bits.

If you don't mind sending me your email address via a PM, I can email
you the code (pretty short).

Thanks!
Jun 18, 2009, 04:03 AM
Fly, fix, repeat
oobly's Avatar
Hi all,

Quax, thanks for all your hard work in getting the code working! Seems the flea is becoming the most popular ESC for 1s use!

Is anyone here running a flashed 6A ESC with HP-06s motor? I have my AVR programmer all hooked up to the ESC and about to flash, but I want to know if it will actually be worth it or if I will be making a useful ESC (for Losi 10250kv) less valuable (if it STILL won't start or run an HP-06s at full throttle an now has no LVC).

-Oobly
Jun 18, 2009, 01:57 PM
Fly, fix, repeat
oobly's Avatar
Hi again,

I flashed the ESC and reconnected it and I get three notes on startup, rising in pitch and then... nothing. Did I damage the ESC when soldering or desoldering resistors (to undo the LVC mod) or is there some startup sequence details somewhere?
Jun 18, 2009, 03:14 PM
Registered User
quax's Avatar
Quote:
Originally Posted by oobly
Hi again,

I flashed the ESC and reconnected it and I get three notes on startup, rising in pitch and then... nothing.
....
I'm missing the 4th note. At startup there is a power off control, that the motor does not start with full throttle. For a short time but more than 10 pulses the throttle signal has to be shorter than 1.1ms, means has to be power off for 10 consecutive pulses. Then the 4th tone will follow.

Some transmitters are near to that limit. Maybe it's worth a try to put the trimmer also down to minimum.

cul
quax
Jun 18, 2009, 03:18 PM
Registered User
Quote:
Originally Posted by blackmoon
unfortunately, I think you still have to mode it to accept 1S.

Under this conditions, you are better to build a FLEA with the DIY kit that Nanofreaks offers at least you won't have to search and buy all the components by yourself.

If you go and buy all the needed components says via Farnel, you almost have to pay the same price as NanoFreaks propose on his site.

At least it is like that here in Belgium, dunno for you guys in the US.
hey blackmoon...nice to see somebody from belgium..doesn't happen that often. I was wondering some ago about a DIY flea that i was thinkinh of buying (from a german site that might have been nanofreaks).

Problem was i didn't know if it was the fast or the slow flea so i didn't know if it'd be suitable for a tail.
(what IS the use of a slow one??? seems you're always better of with a fast one right???)
Jun 18, 2009, 04:24 PM
Registered User
quax's Avatar
Quote:
Originally Posted by mattijs321
....
Problem was i didn't know if it was the fast or the slow flea so i didn't know if it'd be suitable for a tail.
(what IS the use of a slow one??? seems you're always better of with a fast one right???)
Hi mattijs321,

the slow flea is for the main rotor and the fast one is for the tail.
Fast means, that the motor PWM follows the input PWM very fast. For the tail this is necessary. But it's better for the lipo and for the motor to do it smooth Therefore it is better to be slower for the main motor.

cul
quax
Jun 18, 2009, 04:26 PM
inventor of flames decals.
robZulu's Avatar
fast or slow just depends of bridge-ing pins of the atmega. see here: http://www.nanoheli.net/nanoheli/dok...configuration/
fast on the main is ok, but not necessary
Jun 19, 2009, 06:02 AM
flying beam
blackmoon's Avatar
Quote:
Originally Posted by mattijs321
hey blackmoon...nice to see somebody from belgium..doesn't happen that often. I was wondering some ago about a DIY flea that i was thinkinh of buying (from a german site that might have been nanofreaks).

Problem was i didn't know if it was the fast or the slow flea so i didn't know if it'd be suitable for a tail.
(what IS the use of a slow one??? seems you're always better of with a fast one right???)
Hi mattijs,

Yeah it's nice to see some Belgian people here.
Jun 24, 2009, 04:21 AM
Fly, fix, repeat
oobly's Avatar
Quax, thank you for your help. I reflashed the ESC last night (with version 7) and resoldered it and now it works!

It still seems to struggle to start the HP-06s, but it runs it just fine once it is going.. actually runs it very well!

Are there any programming options or does it just set the throttle according to set pulse widths? If so, do you know what I should set my throttle endpoints to on a DX7 radio to get the full range?

Which firmware version do you recommend for the HP-06s motor (high speed outrunner)?

Sorry for asking so many questions, but I want my heli performing the best it can
Jun 24, 2009, 04:53 AM
Registered User
Quote:
Originally Posted by oobly
Quax, thank you for your help. I reflashed the ESC last night (with version 7) and resoldered it and now it works!

It still seems to struggle to start the HP-06s, but it runs it just fine once it is going.. actually runs it very well!

Are there any programming options or does it just set the throttle according to set pulse widths? If so, do you know what I should set my throttle endpoints to on a DX7 radio to get the full range?

Which firmware version do you recommend for the HP-06s motor (high speed outrunner)?

Sorry for asking so many questions, but I want my heli performing the best it can

I'll start off sayin i'm not a coder or really understand what i just did...that said.

Been trying to get HP03 running No luck till now. I changed

.equ PWR_STARTUP = MIN_DUTY+15
.equ PWR_MAX_STARTUP = MIN_DUTY+35

it was

.equ PWR_STARTUP = MIN_DUTY
.equ PWR_MAX_STARTUP = MIN_DUTY+20

out runners need more power to get running. Well what i thought and appears to work Guess need some tuning Hope Quax can sort that
I edited pwm_r02 ICP mod which is different than yours but something to think about!?

Just tried it on 2g no luck ;(


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