SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
timecop's blog
Posted by timecop | Jun 21, 2012 @ 12:17 AM | 36,779 Views
I've had this stuff around for a while, but had no time to write stuff up.
So instead of letting the pics rot, I figured I might as well post it.
Hopefully some people find the info useful.

Here's some details about the ZeroUAV YS-X6 system:


Top side of main controller contains the LM2596 SimpleSwitcher DC/DC module for taking battery voltage down to 5V levels for the rest of electronics. Unlike DJI, Y6 MC communicates using RS232 - so there's a Maxim MAX3243 3/5 channel TTL>RS232 converter. The rest of components are passives/crystal/headers. Of interest is 3 FETs for driving RGB led strip near the bottom center of mainboard.


Bottom side is a bit more interesting, containing the main processor (Atmel AT91RM9200CJ), a 180MHz, 32-bit ARM920 MCU with 64Mbyte external SDRAM (HY57V64162) and 4Mbit Atmel DataFlash for firmware (AT45DB041D). There's also an Altera Cyclone EP1C3T100C8 FPGA, it's purpose isn't really obvious (at first I thought code / firmware protection but that's not the case), maybe it's used for PWM generation/capture. It could also be running the actual IMU fusion code, who knows. Anyway, it's there. It's loaded from Altera EPCS1N config flash, and driven my 50MHz oscillator. There's also an AD7997 10bit, 8 channel ADC with I2C bus, which is probably used for battery voltage monitoring (the ADC on AT91 must really suck).

...Continue Reading
Posted by timecop | Feb 16, 2012 @ 01:39 AM | 382,621 Views
This is going to be pretty much against everything I've been posting here for the last year but hey, if it works, ship it!

Remember blog last year about lack of innovation in multirotor scene? Well, nearly a year later, and nothing changed.

Tardupilot Mega 2 has been released and is solid unobtainium. But let's take a look what it offers? Same old obsolete 8bit processor. A minor sensor refresh, switching to all-digital sensors (more on this later). A new form factor, but still full of headers and heavy/ugly. Then there's the lies about "3 processors". They're not even using MPU6000 DMP/sensor fusion stuff, it's still same ol' tarduino/AVR for main processor, and I dunno what butt they're pulling the 3rd processor from. Maybe the Atmega32U they're using for USB interface.

DJI released their "hobby" version of WK-M and promptly overpriced it. It would be cool if those guys could eventually figure out how to do PPM input and how to set ESC arming pulses to 1000us and not whatever they're doing.

Openpilot is still failing to meet demand, having production troubles (again), is in the middle of switching gyros on CopterControl, and Revolution platform is still being worked on. So you can't get a CopterControl even if you really wanted to, though demand has been slightly reduced by people buying DJI Naza and selling off their CopterControls

I had pretty good success with my 8bit flyingthing using analog Invensense gyros and ADXL accel. I did a test...Continue Reading
Posted by timecop | Dec 05, 2011 @ 05:23 AM | 43,421 Views
A couple interesting things happened while I'm busy flying the awesome ESC. I've been toying around with the idea of getting my AfroI2C i2c>pwm converter for MK junk to do something more useful. With my recent port of MultiWii to STM8 (and soon STM32), I cleaned up the code enough so that supporting I2C converter as a flight board was just a matter of couple #defines. I used (generously loaned by DroneBuilder) latvian I2C sensor board "allinone" (as much as I hate that name) with 5V llc (converter runs at 5V, it *can* perfectly fine run at 3V, then no llc is needed - exercise to the reader) as a test - all sensors worked and displayed reasonable readings in GUI. I don't feel like taking it out for a flight though.



The other thing is I've reached what I consider "production" version for my AfroFlightST flight controller. It's the one in previous blog, with obsolete 8bit micro, invensense gyros, and adxl345 accel on SPI bus. They're available at the usual places. Not to be outdone by the Chinese, I called the new board "Naze". It runs multiwii port to STM8, and supports PPM input and up to 6 motors or 4 motors/2 servos. Size is 36x36mm (thanks OpenPilot) so its nice and compact for those indoor micro-quads.



The board flies pretty good, definitely good enough for me.

aerial failography [naze fc] (1 min 42 sec)

...Continue Reading
Posted by timecop | Sep 23, 2011 @ 01:27 AM | 71,004 Views
I got my package a couple days ago but didn't have time to screw around with it until today. There has been a bit of misinformation and "covering up" made by DJI and their dealers, so I figured I'll post some non-bs info.

First things, nice packaging.

Without the PMU (Proprietary Power Management Unit) the entire setup draws a hefty 650-700mA. This definitely explains why some people have been having heating BEC issues. Cheap 7805's inside a typical HK esc dropping 12-16V down to 5V would generate a ton of heat at 700mA. Lessons learned: use the PMU

The GPS does have a battery backup, and appears to be using ublox neo GPS module with label removed, according to the comments in this post. Compass is, oddly, HMC5883. The entire GPS setup is driven by an Atmel SAM3 Cortex-M3 processor. HMC5883 is NOT on a separate power supply, but I guess since there are no other sensors (besides GPS) on the same voltage rail, that's not so bad, and the 4.7uF (or larger) cap that the chip requires is quite far from the IC itself - that's a bit puzzling, as most problems associated with this compass have been due to the cap being too far or routed through too many vias, affecting measurement.

The "proprietary DJI bus" is actually CAN-bus. There's probably telemetry and other useful info on it, but I didn't bother looking too much into it. Pinout is something like VCC/GND/CANH/CANL.

The status led is blinding. Do NOT look into it while it flashes, you will die....Continue Reading
Posted by timecop | Jun 24, 2011 @ 08:21 PM | 47,801 Views
Where's the innovation in multirotor scene? You can count the number of people actually moving it forward on the fingers of one hand. The rest just rehash same old boring designs and stagnate development by copy pasting the same boring code.

Despite 8bit MCUs being totally dead I thought I'll give them one last chance, but instead of using old and boring Atmel stuff, I went for a more modern device that actually runs at 3V and has proper bootloader, proper ICD, etc. I HATE pcb standoffs. So the other requirement was only in-plane mounted sensors. No surprise, but digital sensors still suck. So I went for analog XY/Z gyros from invensense (IDG/Z500), and SPI digital accel (ADXL345) from ADI. Yes, its digital output but it's SPI and I can clock it at 8MHz instead of ridiculous 100-400kHz joke of a bus that Nintendo accessory tear down crew keeps using.

It's 2011, and anyone still using giant receivers with 12 channels lined up on a 2.54mm spaced row of headers is living in the past. The board only takes PPM input - single servo wire for up to 12 (or more?) channels. When someone donates me a SBus receiver I might change my mind, but seeing how it's limited to Futaba and their extremely overpriced gear, I doubt anyone would be willing to part with one. So I will keep using my FrSky combo which can output PPM with firmware update, and I'm first in line to get a bunch of D4FR which output PPM by simply jumpering 2 pins.

ADC on STM8S is very fast (and accurate) unlike the...Continue Reading
Posted by timecop | Apr 13, 2011 @ 07:09 AM | 47,257 Views
Status: [COMPLETE]

Current status:
Code:
   1. Planning 
   2. Schematic + Layout
   3. PCB + Assembly
   4. Flying test
-> 5. ????? <- Now here
   6. Profit
What was I thinking? Molex SUCKS. Presenting ATmega644-based modular Flight Control board "AfroCtrl"

* Modular sensor backs so I can test out some awesome analog sensors
* Default sensor back has analog Accel, analog Gyro, pressure sensor (on back) + pads for digital magnetometer.
* On-board switching regulator for like 2-3A current (the board uses like 30mA lol). No more Recom, -$12 from BOM cost!
* Spektrum/PPM in/Buzzer connectors on servo-style headers.
* Idiot-proof power header - plug it in backwards and MORON led lights up!
* 1mm thick / 2 layer board
* 50mm / standard FC mounting holes
* The BOM cost on this one is so low I can't even post it here. Nobody will ever buy a single KK board after that.



I've "ported" (spent 5 minutes changing ADC inputs) MultiWii and Shrediquette firmware to this board. Oh, I think it works with MK firmware too, but I wouldn't recommend running Holger$ code on anything but their hardware!


Some random quad I made with AfroCtrl+AfroI2C+HobbyKing Blueseries ESC+KDA 20-22L motors
Posted by timecop | Apr 13, 2011 @ 07:05 AM | 45,029 Views
Status: [DONE]

Cutting apart Turnigy Plush and resoldering stuff is stupid. Let's make something that doesn't suck. Apparently nobody cares about having a cheap ESC, so this is my own for-fun project. I even got trolled into thinking someone cared, only to find out they were a huge Atmel bigot.

This project is back on track because I got tired of wanking around.

Project thread: http://www.rcgroups.com/forums/showthread.php?t=1378680

This will be a two-designs project. One revision will be using the crappy ATmega8 because that's what all the other HK ESCs use. The goal here is "make garbage fly".

Current status of design 1:
Code:
   1. Planning 
   2. Schematic + Layout
   3. PCB + Assembly
   4. Flying test
-> 5. ????? <- Now here
   6. Profit


AfroESC test #2, serial setpoint control (0 min 41 sec)

...Continue Reading
Posted by timecop | Apr 13, 2011 @ 07:04 AM | 43,669 Views
Status: [COMPLETE]

While I'm jerking around with the ESC of Doom, I thought a temporary measure would be to suck it and make an I2C converter. Oh, did I get carried away here. I made not one but two different revisions, and learned a new awesome MCU in the process. Conclusion: Atmel sucks.



Current status:
Code:
   1. Planning 
   2. Schematic + Layout
   3. PCB + Assembly
   4. Flying test
   5. ?????
   6. Profit
-> 7. Nintendo <- Now here

Posted by timecop | Feb 03, 2011 @ 06:23 AM | 44,166 Views
Quadrotor fireworks (0 min 30 sec)


Now I just need to figure out how to remotely detonate stuff.
Posted by timecop | Jan 29, 2011 @ 04:54 AM | 45,735 Views
Main ingredients:

2x 120mm center plate made from 1.2mm FR4 by my pcb house
1x 10x10mm aluminum pipe (1 meter)



1x Quad power distribution board (Actually, I cheated and got one from China, but later made my own design which I will use for the next quad.
...Continue Reading
Posted by timecop | Jan 26, 2011 @ 08:47 AM | 49,682 Views
Status: [COMPLETE]

I heard you like cloning? I make clone of a clone, so I could clone while I clone.
Blog thread: http://www.rcgroups.com/forums/showthread.php?t=1300414



Current status:
Code:
   1. Planning
   2. Schematic + Layout
   3. PCB + Assembly
   4. Flying test
-> 5. ????? <- Now here
   6. Profit
Everything works as planned.
Features over the ChinaFC-1.35:

* 4 layer PCB with proper ground / power plane
* Pan/Tilt/??? servo output like on OEM MK 2.x
* 3V reg for Spektrum-satellite receiver
* Switching DC/DC regulators instead of 7805
* MK-compatible molex connector for distribution board for I2C/Power/Buzzer
* $68 BOM cost
Posted by timecop | Jan 26, 2011 @ 04:23 AM | 79,012 Views
I started this thread in January and I thought people would care.
Apparently, they don't. Well, at this point neither do I. I just want stuff that works, and tearing up Chinese ESC to try out fail firmware written in assembly is not high on my list of things to do when I just want to fly garbage.

I tried to get some help from people but as most of you probably know, RC hobby is all talk and trolling and then there's one-two smart guys who won't share anything with you.

Originally I wanted to make something that would fit into MK-distroboard.
Well, that idea was a disaster because that basically limits me to using dumb parts in dumb form factor. Screw it. New plan:

42x24x4mm.

I found a Chinese company who made separate power stage PCBs. What this means for me? I can make any (cheap) logic back for it and use (really cheap) Chinese power stage board for the rest. That means: single-sided, 2 layer design for my logic board. I'm way to lazy to assemble double-sided designs. This sandwich PCB sounds like a total win from manufacturing standpoint.



The current logic board (above) will solder on the back side of the power stage (below).



And you got some fets on the back side, Turnigy plush style:

...Continue Reading