Moving to new domain

In the past 2 years I have posted many articles about drones here. was supposed to be my personal blog, so I decided to create All articles about drones will be redirected to the new domain in the next few days. Any feedback is welcome. I hope you will like the new design too.

Is ESC without BEC an OPTO ESC – some quick explanation

I will try to keep it super simple (KISS) and explain why an ESC without BEC is not necessary an OPTO ESC. BEC stays for battery eliminator circuit. It is an electronic circuit, which delivers power to other electronics, like your flight controller or receiver. That is why we connect the red wire of the servo cable to the FC, it simply outputs (hopefully stable) 5V.

Some ESCs don’t have an integrated BEC and can not supply power for your controller or receiver (for example: KISS ESCs, Afro Race Mini 20A or XRotor 15A). In this case you need a separate BEC for powering them. There are also power distribution boards with integrated BEC. I personally use the ACSP3 from Nick Arsov.

So far so good. The problem is many ESCs retailers and manufactures (mostly Chinese) don’t know, that an OPTO ESCs is just not equal to ESC without BEC. OPTO means that the ESC have an opto-isolator. If you Google it, you will find that, it is a optical component that transfers the signals between two isolated circuits by using light. The main purpose is to prevent rapidly changing voltages or high voltages on one side of a circuit from distorting transmissions or damaging components, like the receiver, on the other side of the circuit.

I have never experienced any problems with my not OPTO isolated ESCs, but thought it is good to know what an OPTO ESCs really means.

Preview: Naze32 rev6

About month ago AbuseMark released the next version of his famous flight controller – the Naze32 rev6. I am still considering, if I should replace my Naze32 rev5 or my CC3D. Here I will share my thoughts about it.

What’s new:

  • Invensense MPU6500 replace the old MPU6050 gyro
  • Added BMP280 Bosch barometer
  • Spektrum satellite receiver port
  • 16Mbit SPI flash memory
  • SBUS inverter
  • Pads for direct connecting a Sonar
  • Through pin holes for the receiver

The new MPU6500 gyro and accelerometer allows communication per I²C and SPI too. Sadly the MPU6500 is still connected via I2C (unlike other F1 boards with MPU6500, Paris Air Hero32). Because of this, if you are planning to use the Cleanflight firmware on the new Naze32 rev6, you need to wait a bit for a stable release.

Having a barometer is a nice feature, but I am not sure if it is needed on an acro quadcopter. I have an upgraded Naze32 rev5 with barometer on my SG Acro and have never used it.

Through pin holes for the receiver are very welcome, as many pilots (including myself) have broken the receiver pads after crashing.

If you are using Spektrum Satellite or SBUS receiver, you don’t need to hack the Naze32 anymore. These can be easily connected now.

You can now use the integrated 2MB flash memory on the Acro Naze32 rev6 for logging data (blackbox feature).

The new Naze32 rev6 have a bit changed design. The USB port is on the right side now. When powering the Naze32 rev6 via PC-USB, you need to know following fact: your receiver is now powered too. That’s the good news. The problem is, that the ESCs are powered too, because 5V are going to the servo rail.


Most of the changes on the Naze32 rev6 are very welcome. Yes, the processor is still the STM32 F1 and not the newer F3 or F4, but it is ok if you are using these kind of sensors. Is it worth spending 25$ for it?

Yes if:

  • You really need the 2MB flash and don’t want to solder it on your own on the old Naze32.
  • You are planning to use SBUS receiver and don’t want to use a separate inverter or do hacks.
  • You neither have the old Naze32 nor want to install Cleanflight on a CC3D.
  • You can’t go flying without barometer 😀

I will personally stick to my Naze32 rev5 or CC3D for now. It is not a secret, that I still prefer the CC3D, because of its integrated 2MB flash, SBUS inverter and better price.

ACSP3 – Current, voltage sensor and power board

Nick Arsov, the developer of the AUAV-X2 autopilot, presented some time ago his new current and voltage sensor – the ACSP3. As I needed a power distribution board for my new SG Acro v1.1 quadcopter, I decided to give it a try.


  • Max Input Voltage (Vin) = 42V; So possibility of use a 10S LiPo battery.
  • I-shunt = 90A; You will be able to measure current up to 90A.
  • Vout = 5.3V; Great if your ESCs have no integrated BEC and you need to power the FC.
  • Iout = 2.25A; Enough to power your flight controller, receiver, GPS and so on. Here some data.
  • Ultra low noise: <10mV
  • Analog interface
  • I2C interface; works great with my Arduino Uno.
  • Dimensions: 30x30mm. Mounting holes: 22.5×22.5mm.
  • 8x male headers pre-soldered.
  • Weight: 4.4g


  • Voltage and current sensor for AMP, Pixhawk, AUAV-X2 and all PX4 based flight controllers.
  • Distribution and power board for every 5V tolerant flight controller (Naze32, KK2.1.5, CC3D). You don’t need ESCs with integrated BEC or separate BEC.


ACSP3 BackACSP3 Front

I soldered a male XT60 connector (for use with all my 1300mAh LiPos) to it and then integrated the ACSP3 into the acro quadcopter.

ACSP3 XT60SG Acro v1.1 Weight

Using the I2C interface with Arduino Uno: download the code. It is slightly updated by me, because the final version of the ACSP3 is rated for 10S and not for 6S as the beta). Upload the file to your Arduino and connect all four wires from the I2C interface as described in the code. Using the Serial Port you can check the current and voltage.

You can use it straight away with your AUAV-X2 flight controller. If you have a Pixhawk controller, you need to modify the cable to fit in the Pixhawk voltage/sensor port. Not sure if it is possible to order such one from Nick´s webshop.

The quality of the ACSP3 is great, but the price is in my opinion a bit high: 29$ plus shipping from here for USA. If you want just to power your flight controller on an small quad, you can go for a simple BEC. For those of you who need cheaper voltage and current sensor for you Pixhawk, use this power module.

But If you are planning to build an expensive copter for work, then you definitely need the reliability of the ACSP3.

FQ777 Pocket Drone 124 – евтин мини квадрокоптер

Квадрокоптерите или още наричани дрони стават все по-популярни, а с това и броят на желаещите да пилотират тези “играчки”. Много хора си задават въпроса какъв дрон да си купят или как да си направят собствен дрон. Преди време написах упътване и какво бих препоръчал аз. В следващите редове пък ще споделя впечатленията си от мини квадрокоптера FQ777.

Това квадрокоптерче не може да се мери с големите си събратя, но и няма претенции за това. То за разлика от тях е играчка, макар и не позволена за деца под 14 години.

Уникално нещо при него е дизайнът на радио управлението. Проектирано е така, че да може малкото квадрокоптерче да бъде прибирано и пренасяно в него.


Резервните перки и протектори също намират място в корпуса на дистанционното, но в задната му част. Лично на мен идеята и изпълнението ми допаднаха много.

Самото радио управление се захранва от 4 стандартни батерии тип АА, които не са включени в комплекта. Мястото за тях е под двете черни пластмаси, след като се развият две малки болтчета.


Не знам дали не прочетох правилно упътването или упътването не беше правилно, но имах малък проблем със свързването на квадрокоптерчето с дистанционното. За да успея да го подкарам първо трябваше да включа самото квадрокоптерче, след него радио управлението и накрая да преместя стика за газта веднъж нагоре и след това надолу. Ако процедурата е минала успешно лампичките на малкия FQ777 спират да мигат и светят постоянно.


Летенето за мен беше много по-лесно отколкото с истинските ми машини, но за абсолютни начинаещи ще изисква търпение. Двама от четирима приятели на които го дадох свикнаха да го управляват в рамките на 4-5 мин. Общо взето и батерията се изхабавя за толкова. Зареждането става с USB кабел, който се включва примерно към компютъра.

Заключение: мини квадрокоптерчето е идеално за зимните месеци, когато е студено и искаме да се забавляваме в къщи. Управлява се лесно, компактно е и е трудно да нарани някой или нещо. В никакъв случай не може да се сравнява с големите машини и удоволствието от летенето с тях, но е подходящо за подарък. Цената му директно от Китай е 16$ с включена доставка. Тъй като сумата е под 22евро няма да има допълнително ДДС или мито.

Безжично зарядно Nillkin Magic Disk II

Като фен на безжичните технологии реших да изпробвам едно евтино и добре изглеждащо безжично зарядно за смартфони. Дизайна ме грабна, цената беше атрактивна и реших да поръчам зарядното на китайската компания Nillkin – Magic Disk II. Тествах го как работи с един Samsung Galaxy S6 Edge.

Зарядното пристигна добре опаковано и без никакви щети по време на транспорта от Сингапур. Освен него в кутията имаше стандартен USB кабел и упътване на английски. Можете спокойно да ползвате вашият адаптер за зареждане и да включите Nillkin към него.

Индуктивното зарядно на Nillkin е компактно (100х100х10.4мм) и както споменах с много добър дизайн. Налично е в два цвята: бял и черен. По-голямата част от него обаче е прозрачна. Изработката е добра, не изглежда евтина, но и в никакъв случай не е от премиум класа.


Зарядното може да зарежда с максимално 1А ток, което е стандартното, но няма да поддържа “Quick Charge” технологията (до 3А ток). От долната му страна има гумени крачета, за да не се плъзга. От горната също има гумена обвивка, която не позволява на телефона да падне.


След поставянето на телефона върху него, зареждането започва автоматично. Докато той е поставен отгоре, зарядното свети в лека ненатрапчива синя светлина. Идеята ми допада, защото веднага се вижда дали връзката е осъществена. Това обаче може да не се хареса на тези, които искат да държат зарядното до леглото през ноща.

Ето как изглежда и спрямо зареждащия се Samsung Galaxy S6 Edge:


Разбира се зарядното може да бъде ползвано с всички смартфони, които поддържат безжично/индуктивно зареждане (примерно Google LG Nexus 5 и Nokia 920).

Заключение: за непретенциозната си цена от двайсетина долара, безжичното зарядно върши перфектно работата си, а добрият дизайн радва окото и любопитните гости :-).

HobbyWing XRotor 15A ESC with “OneShot” and Damped Light

Two weeks ago I posted an article about the XRotor 10A ESC, which I wanted to use for my next acro quadcopter. I wanted to download the English manual from the HobbyWing website and noticed these new XRotor 15A ESC. The XRotor 10A performs in my opinion great compared to the SimonK and BLHeli and HobbyWing claim these new XRotor 15A are even better than SimonK and BLHeli ESCs. I wanted to know what the difference is and asked the HobbyWing support team. This is the info that I got:

  • The new XRotor 15A does not support signals with refresh rate up to 621Hz like the 10A version.
  • The new XRotor 15A support “OneShot” and “DEO” (which is like “Damped light” on BLHeli or comp_pwm and motor_brake on SimonK). The old 10A ESC does not support these functions.

HobbyWing made some tests and claim that these new ESCs have better efficiency and lower temperature. So I decided to give these ESC a try and ordered 4pieces for the acro quad.

The ESCs came extreme quickly from Hong Kong to Germany, only 10 days. Before I mount them on the quadcopter I wanted to know what’s inside under the heat shrink, so opened one and made some photos.

The ESCs are a bit bigger and heavier than the XRotor 10A. Unlike them these have longer motor cables and some other type of gold connectors.


On the backside you can see the IRFH8318 MOSFETs. These are rated to 30V, so maybe flying on 4S could be possible. Here you can find the datasheet.


On the front side the XRotor 15A is completely different from the XRotor 10A. I will check and ask what the elements exactly are, as I cant find any information right now.


  • MPSF34 / MP6530 – Brushless DC Motor Pre-Driver by Monolithic Power Systems (Max 60V).
  • HW503 / 515AB – I can’t find any information about this chip. (Thanks to QuadMcFly from RCGroups, who corrected me, that it is not HH503).

I will update the article as soon as I mount these on my SG Acro v1.1 quadcopter with the T-Motor MN2206 and give them a try.

Update 30.09.2015: The ESCs are already mounted on my acro quadcopter and they perform very well. OneShot is activated and I have no sync issues with the T-Motor MN2206. Active breaking is about the same as on HK BlueSeries 12A with BLHeli, but in my opinion not so great as SimonK with comp_pwm and motor_brake enabled. The ESCs are rated for max 3S, but I have tested them successfully on 4S with no problems. They don’t get warm and I haven’t experienced sync issues. Here a picture of my SG Acro v1.1 with the ESCs heatshrinked directly on the arms. I can’t tell for sure if these ESCs have higher efficiency than BLHeli or SimonK ESCs, as this is hard to test without a power meter. If this helps you, I got about 14min mixed flight time (Quad weight is 270g without the 4S 1300mAh battery; props are 6” carbon).DSC_3436