Quick review: Turnigy 2730 1500KV brushless motor

I’ve bought first Turnigy 2730 1500KV brushless motor by accident. I needed something small and cheap for Depron airboat. Then I needed something similar for a Depron airplane. At the end, in 6 months, I owned 3 T2730 1500KV motors. Not all of them survived the experience. One got lost in the middle of a lake with the rest of airboat it powered. Second got burned what I forced it to power too big propeller. Third one still lives and this type is my first choice for anything up too 400g of weight.

Turnigy 2730 brushless outrunner motor Continue reading Quick review: Turnigy 2730 1500KV brushless motor

Raspberry Pi: reset external I2C devices (not only I2C)

Electronic, and specially computerized, devices likes to hang from time to time. There are many reasons: software bug, hardware error, voltage drop, interference, too long wire, random incident. I’ve learned this hard way during work on my Raspberry Pi based weather station. From time to time external DTH22 temperature/humidity sensor refused to work. Only solution was to cut power to DHT22 for a second (or less). It was kind of irritating to go the attic, unplug sensor and plug in again. Later on I had similar issues with HD44780 LCD display over I2C bus. Device was hanging and only solution was to cut power. So, I’ve found a solution: as a prevention cut power for a second every 30 minutes with a simple electronic device I’ve called “Power Cutter”.

Raspberry Pi power cutter

Continue reading Raspberry Pi: reset external I2C devices (not only I2C)

Detecting Cleanflight PID tuning issues with Blackbox: excess P gain

Almost all quadcopter PID tuning tutorials can be summarized into one sentence: “Increase P until you see oscillations, then lower it”. Plus some thoughts about I and very vague advices about D and that is all. When I got into the hobby, I’ve read all of those tutorials. And I did know more about PID tuning than before that. I even had more questions than before. How to recognize high frequency oscillations, how to recognize low frequency oscillations. Lower P? OK, but how much? And D? How to tune this bloody D? As a result, every time I tried, I ended up with very snappy but shaky quadcopter that maybe responded very quickly to commands, but was very shaky and was making strange noises.

And then came Cleanflight and Blackbox. Live became simpler. What I’ve learned from Blackbox logs is that I wanted high P so much, I had too much of it in the end. Actual oscillations begins before we see or hear them and excess D introduces jello. Blackbox simplified things, but still, logs analysis is something like an art. You have to know what to look for. Continue reading Detecting Cleanflight PID tuning issues with Blackbox: excess P gain

Best drone for Christmas

Christmas is upon us. Less than 2 weeks to be precise. Since drones are such a hot topic, many will want to get one for Christmas, many will want to buy one as a gift. There are so many of them at the market, it’s not a problem to buy one. It’s a problem to choose correct one, so that everybody is happy. Sure, everybody would like to get DJI Inspire 1 for Christmas, but I do not think that’s a point here. So, here are my recommendations for todays question: “What is the best drone for Christmas?

First drone for indoor flying

They are small, they are cheap, they are almost indestructible and rooms are their natural habitat. Nano drones. Excellent idea for a Christmas present. Cool enought to give joy and cheap enough that it will not be huge loss if they will be thrown into a corner or destroyed after few days. Additionally, low weight, low speed and small propellers greatly reduces chance of destroying something or causing injury. In this category I want to recommend Hubsan X4 H107.

Hubsan X4 H107

Continue reading Best drone for Christmas

Quick review: Eachine PCB Power Distribution Board for ZMR250/QAV250

Building a quadcopter without nice power distribution board always leads to the same result: state of total cable entanglement. It looks ugly, makes maintenance hard and adds unneeded weight. I will not show how my ZMR250 quad looked after I added FPV and OSD into it. Almost all space between top and bottom plate was taken by cables. Nightmare. So, after spending less than $9 I’ve become an owner of Eachine PCB Power Distribution Board w/ OSD Socket Support NAZE32 CC3D OSD For QAV250 Quadcopter from Banggood. This board did not have very good reviews, but offered three things I wanted: sockets for micro MinimOSD, integrated signal lines and low price. So, I gave it a try.

Eachine PCB Power Distribution Board w/ OSD Socket Support NAZE32 CC3D OSD For QAV250 Quadcopter Continue reading Quick review: Eachine PCB Power Distribution Board for ZMR250/QAV250

Indoor FPV quadcopter flying: first attempts

Last Sunday I had a possibility to try something new: indoor FPV flying with a 250 class quadcopter. I am not a FPV expert, I can not do all those awesome stunts, but I feel pretty confident in air. It does not scares me anymore, and I’m not affraid to make a longer flights with my Reptile 500 multirotor. But indoor is something different, it takes FPV to a completly different level comparing to outdoor. And here are my thoughts about the experience.

Indoor FPV room

  • No matter how big indoor is, it is never as big as a meadow. We had about 3400 square meters at our disposal and the last thought was: I have a lot of space to make this turn. 3400 square meters is a lot, but it does not look so spacious through camera,
  • Comparing to outdoor, indoor FPV is 5 times harder? Why? Outdoor you have only one enemy: ground. Indoor you have floor, roof, 4 walls and most probably additional obstacles. Hitting any of those results in crash,
  • Outdoor when you are lost you can always go up. After all, noone ever crashed into a sky. Indoor it is not an option. Roof is a sneaky bastars. It sits there quietly and waits for your patiently. I was so used to avoiding the ground, that I was flying too high. Roof was there of course. And hitting a roof is a combo. First you hit the roof, and a second leter you hit a floor,
  • Everything is hard. Roof is hard, walls are hard, floor is hard. In most cases made from concrete. And thust me on that, in all the cases, concrete wins. It wins with propellers, motor bells, motor shafts, carbon fiber. It just wins. Period. 30 minutes in the air costed me: unknown number of props, one ZMR250 carbon fiber arm, one Multistar v2 2206 2150KV “Baby Beast” motor. And condidion of a second motor is iffy. It does need immediate replacement, but it will not survive another beating like that,
  • It is weather independent! Rain, snow, wind, night, does not matter. You are indoor. Keep flying,
  • If electricity is there, so you should be able to recharge LiPos,
  • Adrenaline is high and it is fun.

Will I try it again? Yeap, only after rebuild my ZMR250 quad. Replacement motors are on the way…

Cleanflight 1.11 is on its way

Looks like there will be a new release of Cleanflight flight controller software before Christmas 2015. Version 1.11.0-RC1 has been tagged 10 days ago. So, maybe even this week if there will be no bugs. What’s new in 1.11? No, no Betaflight yet, and no iNav (Navigation Rewrite). Some improvements, new supported hardware (Naze32 Rev6 and RMRC DoDo), some bugs fixed. But with 1.11 some features will be removed as well.

First of all, number of PID controllers has been cut in half. PID Controller 0 (MultiWii), 4 (MultiWii 2.3 Hybrid) and 5 (Harakiri) has been removed and will be no longer available. Why? They were not very popular (maybe besides default PID 0) and they were using precious space in flash memory. This is the most important signal that lifetime of STM32 F1 based flight controllers is coming to an end. Naze32, Flip32 and others does not have enough flash memory to fit all functions.

Second, Autotune has been replaced with G-Tune. I did not tried G-Tune yet, so I have nothing to say about it. I’ve tried Autotune few times as was not very happy with results. Not only it did not supported PID controller I prefer (LuxFloat), but I also noticed that tuned P value was too high for my needs. So, bye bye Autotune, I will not miss you…

PPM output on FrSky X4R and X4R-SB receivers

FrSky sells 2 small Taranis compatible receivers: X4R and X4RSB. By default, they offer only PWM signal. 4 channels on X4R and 3 channels plus S.Bus (16 channels over S.Bus) on X4RSB. And that is problematic. Many flight controllers does not support S.Bus very well (no inverters) or just does not offer enough UART ports. When speaking of small multirotors, PPM signal is often the best choice. That made X4R almost useless. For X4RSB additional S.Bus-PPM conversion cable had to be used.

Luckily, this has changed, since FrSky started offering custom X4R/X4RSB firmware that allows 8 channel PPM signal on receivers port 1. The only thing you have to do is to flash you receiver. And those are the steps to do it:

  1. Download CPPM firmware from this site. Remember that you need proper EU/non-EU version. It all depends if your Taranis and it’s built in XJT module has EU or non-EU firmware. How to determine EU/non-EU Taranis? If you are living outside EU you probably have non-EU firmware. If you are living in EU but bought from non-EU country (China probably) you have non-EU. Also, if in menu you can select D8 or LR12 internal radio mode, you have non-EU firmware. EU firmware allows only D16 mode,
  2. Follow those steps to flash X4R/X4RSB using Taranis built in port,
  3. Put a jumper on signal pins 2 and 3,
  4. Bind receiver with Taranis,
  5. Remove jumper.

From now on, pin 1 outputs PPM channels 1-8, pin 2 outputs PWM CH9, pin 3 outputs PWM CH 10, and pin 4 outputs either PWM CH11 in X4R or S.Bus on X4RSB. If you want to go back to non-PPM mode, bind receiver again, without jumper on pins 2 and 3.