Sunday, February 19, 2017

Eachine E010 - 4 and 2 blade propeller flight duration test

I have tested the flight duration of Eachine E010 ( with standart 4 blade propeller and custom cut to 2 blade propeller.
Battery used - standart Eachine 30C 150mAh

Test results:
Cutting off 2 blades of standart 4 blade propeller increases efficiency and flight duration up to +25%. You may lose some of the agility but will greatly increase flight times.

Flight duration:
4 blade propellers: 4:46
2 blade propellers: 5:58

Low voltage warning:
4 blade propellers: 2:38
2 blade propellers: 4:56

Wednesday, December 28, 2016

Testing thrust of Eachine E010 stock motor, Chaoli CL-615 and Chaoli CL-615 Upgraded motors for tiny whoop

Today on the bench: thrust test of Eachine E010 stock motor, Chaoli CL-615 and Chaoli CL-615 Upgraded motors.
Motors used in the test:
Eachine E010 stock motors (
Chaoli CL-615 motor (
Chaoli CL-615 pack of 4x motors (
Chaoli CL-615 upgraded motor (
Chaoli CL-615 upgraded pack of 4x motors (
Test results:
Stock motors have shown very good results. Chaoli motors showed even less static thrust than stock motors. Chaoli CL-615 Upgraded version motors are really more powerfull, they spin a lot faster (you can even tell it by the sound of spinning proppeler).
If you decide to swich to the more powerful motors, I would recommend to upgrade a battery to the 45C 150mAh one (, as Chaoli upgraded motors draws more current (4×1.10A=4.40A) and weaker batteries have a lot of voltage sag.

Monday, December 5, 2016

How to fix Eachine ProDVR PAL cropping issue

Good news for Eachine ProDVR and HMDVR users - newest firmware (2016-09-20) really fixes PAL cropping issue! I have flashed old and new firmware several times without problems. So flashing really works and works for both DVR units - ProDVR and HMDVR as these devices have almost identical hardware.

The old firmware. Screenshot from recorded video with OSD data. Notice the 2 bottomn lines of OSD data are cropped: 

New (2016-09-20) firmware. Screenshot from recorded video with OSD data. No cropping!

I have added the firmware file here for your convienience .

Update instructions:

Unplug power from ProDVR. Put micro SD card into card reader and connect it to the computer. Extract CRESFW.BIN file into root folder of the SD card. Put micro SD card into ProDVR. Plug in the power. ProDVR led will start to flash. First slower then faster then slower. Wait about 1 min until the LED will turn off. Dont hurry and dont unplug power too early! After LED will turn off you can disconnect and reconnect power to the PorDVR. Dont forget that you will need to set PAL/NTSC and other settings again as defaults have been loaded. 

Firmware file here: CREFSFW.BIN or here: CREFSFW.BIN

Warning: Flashing ProDVR sometimes ends in bricking the device. You can restore the bricked device with a help of serial flash reader (arduino can be used). Look for the restoring bricked ProDVR instructions.

Thursday, December 1, 2016

Racerstar RF2205 (RF2205S) motor review and thrust test

   I have recently received a set of Racerstar RF2205 2300Kv motors from Banggood for a review. Motors came well packed in a carton box. Package includes motors, bullet type prop nuts and 3mm steel screws. Motors are sold only in packs by 4 (2 CW + 2CCW). It would be great if Racerstar would offer an option to buy single motor. This will enable buying a spare one or a replacement for broken/bent/burnt motor. Personally I would suggest to sell only CW shaft thread version of these motors with a prop lock nuts. Lock nuts hold props hard enough on CW and CCW rotation motors there is no real need of different threads. Benefit of this is versatility of motor use – every motor can be either CW either CCW, no need to have 2 spares and in case of RF2205 - 4 spares.
Comes in packs by four
Motors have solid hard steel shaft. That is one of the reasons why they are heavier than BR2205.
Solid steel shaft and steel screws
There are a lot of cut-outs for air intake on the lower part of the stator. 
Cutouts for air intake and shaft nut
   Also notice that shaft is locked with 2mm hex screw instead of the C-clip. Dont tighten them too much, because plastic washer starts to rub against the bearing and introduces some drag to motor motion. 
Inside of the motor - the bell (rotor) is reinforced and well balanced. The windings are made of multi-stranded copper wire. Magnets are curved and N45SH strength grade. 

• Steel shaft – harder to bend 
• 20 AWG soft silicone wires
• Cut-outs in the bottom plate for air cooling
• Shaft is locked by hex screw instead of C-clip
• Curved magnets, N45SH
• Reinforced and balanced bell 

• Sold in packs by 4 pcs only
• Bullet type prop nuts

   Build quality is high. Thrust results show high static thrust power, one of the highest in their class. My personal opinion - they can be compared with Emax RS2205.

Here is my humble video review of these good motors:

Racerstar RF2205S 2300KV motor review (7 min 16 sec)

Static thrust tests:

Racerstar RF2205 2300KV thrust test (1 min 35 sec)

Tested with:
Batteries: 3S and 4S, 3500mAh 
ESC: Hobbywing XRotor 40A BLHeli 

Tested props:
DALPROP 5045 V2 2-blade
DALPROP T5040 3-blade 
DALPROP T5046 3-blade
DALPROP Q5040 4-blade 
KingKong 6040 2-blade

Monday, November 21, 2016

Restoring bricked Eachine ProDVR after firmware update

If your ProDVR is bricked after firmware update process, you can easily restore it by flashing firmware directly to the serial flash ship.

What you will need:
  • Arduino Mini Pro atmega328 board. (16Mhz 5V, about 1.30$)
It is also possible to use Arduino Nano with atmega328 (16Mhz)
(Possible variants on ebay:, Banggood:
  • USB to Serial adapter. It can be FTDI, CH340G  (just look for ones that support 3.3V , about 1.30$)
(Possible variants on ebay:
  • Thin wires for connecting Arduino and Serial Flash
Next parts are needed if Arduino outputs more than 3.3V on signal pins:
  • Resistors for level divider 5k and 10k both (2 pcs of each value)
  • Breadboard (not necessary, but very convenient)


Flashing Serprog firmware to Arduino Mini Pro:
1.    Connect USB – TTL converter to Arduino Mini Pro board
2.    If everything is ok, You should see “FTDI” or “USB-SERIAL CH340” device in device manager
3.    Connect Arduino Mini Pro to USB-TTL adapter (check that your FTDI or USB Serial adapter uses 3v for powering)
4.    Start Xloader, open [fser-duino.hex] file, set the right com port and hit “Upload”.
Now You have Flashrom compatible programmer.
5.    Connect ProDVR flash IC to the Arduino. Use supplied connection schematics. For this you need to lift a bit VCC pin of the serial flash to disconnect from the rest of the board electronics and solder 5 wires: VCC, GND, CS, CLK MOSI and MISO. Try to keep them as short as possible, about 10cm. Use small diameter wire.
Connection table:
VCC (pin 8 ) to Arduino  3.3V output (5V would likely kill the chip, be carefull)
GND (pin 4) to Arduino GND pin
CS (pin 1) to Arduino pin 10
DO (pin 2) to Arduino pin 12
DI (pin 5) to Arduino pin 11
Clock (pin 6) to Arduino pin 13

Schematics (only if Arduino outputs 3.3V signal levels):
6.    Once connected, try reading the contents of flash IC by running this command:
mingw32-w64-flashrom-r1781.exe --programmer serprog:dev=COM10:115200 -c MX25L1605 
--read test.hex

You should get similar output to this:
E:\My\RC\Flashrom>mingw32-w64-flashrom-r1781.exe --programmer serprog:dev=COM10:115200 
-c MX25L1605 --read test.hex
flashrom v0.9.7-r1781 on Windows 6.2 (x86)
flashrom is free software, get the source code at
Calibrating delay loop... OK.
serprog: Programmer name is "frser-duino"
Found Macronix flash chip "MX25L1605" (2048 kB, SPI) on serprog.
Reading flash... done.

7.    If everything goes OK by this far, you are ready to flash the firmware. To flash the device, start this command:
mingw32-w64-flashrom-r1781.exe --programmer serprog:dev=COM16:115200 -c MX25L1605 
--write flash.hex

You should get similar output to this:
E:\My\RC\Flashrom>mingw32-w64-flashrom-r1781.exe --programmer serprog:dev=COM16:115200 
-c MX25L1605 --write flash.hex
flashrom v0.9.7-r1781 on Windows 6.2 (x86)
flashrom is free software, get the source code at
Calibrating delay loop... OK.
serprog: Programmer name is "frser-duino"
Found Macronix flash chip "MX25L1605" (2048 kB, SPI) on serprog.
Reading old flash chip contents... done.
Erasing and writing flash chip... 
Erase/write done.
Verifying flash... VERIFIED.

You are done! Now reconnect serial flash chip Power pin to the PCB and try to power your ProDVR. You should see something similar to this:

Insert SD card and you good to go!

If you have questions or you need more details, then write a comment.

Monday, November 14, 2016

Eachine ET526 VTX transmitter review

Link to product page:  Eachine ET526 VTX Transmitter

This VTX has 4 power levels: 0 mW – 25 mW – 200mW – 600mW, 5 bands: A – B– C – D – E, 40 channels total. 
Weight is 8.5 grams. This is slightly more than typical VTX weights and this is mainly because of the heat sink attached.

Heatsink plate on the top

LEDS for Band, Channel, Power level ant TX ON indicator

Size is almost the same as other similar VTX‘es

First interesting feature is Transmitting Power OFF on startup. Every time you power this VTX, it starts with TX power OFF (TX led is dim). You have to double click upper button after you power up the VTX to turn video transmission on.
Second interesting feature is on-board microphone, which can be turned ON and OFF 
Changing of the channels and bands is done with lower button pressing. Short press of the button to change channel, longer press (2sec) for changing band and long press (5sec) for on-board microphone On/Off.
Double click of the upper button turns the video transmitting on. Longer press (3sec) changes power level selection 25 – 200 – 600 mW.
Cable is 6-pin JST-SH 1.25mm one. Cable has a 3-pin camera connector on another end of the cable, also female servo connector for Power in (7-24V) and female servo connector for PWM input. Camera connector compatible with Eachine 1000TVL CCD camera.
Antenna connector is SMA type. This is good for VAS/Fatshark users as their antennas have SMA connectors. Others can use SMA->RP-SMA type changing adapter (like this one:

I have measured the output voltage for camera under load (Eachine CCD 100TVL). It turned to be 5.16V while transmitter is TX OFF and 5.19V when TX in ON. The same for all power levels. 

Current measurements
Power level: 0 mW, Power usage: 20mA
Power level: 25 mW, Power usage: 120mA
Power level: 200 mW, Power usage: 210mA
Power level: 600 mW, Power usage: 310mA

• Switchable transmitting power level – from ZERO to 25, 200, 600 mW. 
• 5 bands, total of 40 Channels
• Video transmitter can be turned OFF/ON. 
• Has on-board microphone
• On board microphone can be turned OFF;
• Remembers last settings after power off-on cycle (except transmitting is turned off every time VTX is power cycled)
• Has 5V output for camera
• Channels can be switched by PWM signal from receiver

• You need to manually turn on the transmitter every time you plug the battery. Have this is mind when installing this VTX into your quad/aircraft
• Tends to reset (rarely) to default channel/band after multiple battery connects/disconnects

Additional thoughts
• This transmitting OFF by default feature is good, but not always wanted one. In the future revisions I suggest to make a setting – weather to start the VTX with TX power OFF or to start with TX ON by default. Could be made in such a way: Press upper button for 5 seconds to switch between these two modes
• Bands are somehow mixed up. You have to search for the right band on your RX, because letters doesn’t correspond to usual band labeling.

Eachine ET526 VTX FPV transmitter review (9 min 14 sec)

Friday, November 11, 2016

Eachine TX526 FPV video transmitter review

I have bench tested Eachine TX526 video transmitter, which I received from Banggood. 

This VTX has 4 power levels: 0 mW – 25 mW – 200mW – 600mW, 5 bands: A – b – E – F – r, 40 Channels total. 
Weight is 7.1grams, exactly the same as TX5828. Size is almost the same as other similar VTX‘es:

Size comparison with other transmitters

Changing of the settings can be easily done with just one button. Short press of the button to change channel, longer press (2sec) for changing band and long press (5sec) for power level selection.

It has RP-SMA antenna plug, despite some misleading information on the user manual leaflet. 

Cable is 5-pin JST-SH 1.0mm one. The same cable and pinout fits TX5828 transmitter. 

Current Draw measurements
Power level: 0 mW, Power usage: 40mA
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Power level: 25 mW, Power usage: 110mA
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Power level: 200 mW, Power usage: 220mA
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Power level: 600 mW, Power usage: 300mA
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• Easy to setup – one button. 
• Has 4 power levels 
• Can be set at 0 mW power level (TX off)
• Remembers last settings after power off-on cycle
• 5pin JST-SH (1.0mm) cable, widely used in other transmitters

• None

Additional thoughts
• This VTX has interesting feature - turn transmitting power to 0mW. This setting can be usefull if you want to test/tune your quad in line of sight flight or while making some work on the bench. Also can be usefull for powering quad without VTX on racing events.

Eachine TX526 FPV video transmitter review (6 min 1 sec)

In the second part of the review I will test this VTX in the flight, make a test range, measure temperature and more.

This VTX was provided by Banggood for review

Featured Post

Racerstar RF2205 (RF2205S) motor review and thrust test

   I have recently  received  a set of Racerstar RF2205 2300Kv motors  from Banggood  for a review . Motors came well packed in a carton...