Thursday, February 12, 2015

Inside stuff - JJRC H6C quadcopter

The JJRC H6C looks almost identical to Hubsan X4.

Short review

It's pretty stable out of the box requires a bit of trimming. Plenty of power and does [assisted] flips with ease. Unfortunately the remote is pretty crap (compared to my DX6i) probably from a reused USB gamepad.
The yaw controls affects the throttle, not sure if because of the combined stick usage or something else is happening there.
It's pretty hard to keep a stable hover because of the sensitive throttle. Combined with the issue above it means it's pretty hard to do panning shots - rotating around an object to be filmed.

Camera is of low/mediocre quality, nothing to write home about. It's probably reusing a "spy" camera, similar to the one I wrote about: http://hackcorrelation.blogspot.de/2014/03/inside-stuff-teardown-and-repair-of-spy.html
The sound is mostly from the engines, to get a decent sound you will need to take the complete unit apart and reposition the microphone by soldering new wires.

The microSD card has frequent failures and probably needs to be replaced. I have not run a "true" capacity test on it but it might be 512MB instead of the advertised 2GB.

Flight times are shorter than advertised, probably around 4 minutes until the battery is discharged to a still safe level (3.7V). You do get 5-7 minutes of flight until the automatic voltage shutdown kicks in, but after that the battery only has ~3.3V.
I'm using a 500mA charging adapter instead of the supplied USB "charger", reducing the charge time to ~15 minutes. RC-style batteries are pretty safe to charge at 2C - the included battery is 350mAh - so any charger under 700mA should be ok.

Teardown

It's a two-board construction, with the quadcopter control board and the camera board sandwiching the battery holder.


Microphone is on the lower-right side in this picture, next to the microSD metal shield.


The quadcopter board is based on Invense MPU-6050C 3-axis accelerometer and gyro combination.

Driving all this is a chip marked HL004 436AB 242B014-80 ARM. I assume an 80MHz ARM chip similar to the one used on Arduino Due. This enables leveraging the existing Arducopter code.

Communication is provided by Beken BK2425 chip: http://www.sunrisedigit.com/en/Show.asp?id=38 which is in itself a chip similar to nRF24L01+.

The camera board is connected by 3 wires so I assume power (red) is running all the time while the signal wire (either white or green) is being put to ground whenever a picture or video is required.
The spy pen cameras I have use a short press of the button to take a picture and a long press to start/stop video recording (or viceversa). This means that in case of video it will take at least the long-press duration (3 seconds?) until the recording is really started.







I have not bothered checking what's coming from the test pads.

The double-sided PCB under strong light:

Camera board has a big SoC in the center and a smaller SPI flash chip on the side - BergMicro BG 25Q40A STCG.


The microSD slot on the other side, FFC for the camera and a microphone.

 A picture of how they all fit together.

And another photo showing the battery holder as well.

8 comments:

  1. I have been looking for the battery holder for the H6C for months now with no luck. If anyone has one or can make one on a 3D printer please let me know. rodge402@gmail.com Thank you

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    Replies
    1. Get these batteries, they fit better http://www.banggood.com/X6A-380mAh-Battery-With-Charger-For-Hubsan-H107L-H107C-H107D-H108-H108C-p-976993.html

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    2. I would just use velcro tape to keep the battery in. The battery holder is part of the lower half of the frame, so I assume the entire frame is needed.
      You can take a look at their cheaper models (with VGA only camera or no camera) - they go for around 16$ : http://www.jjrctoy.com/en/goods/44/2.html

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    3. I checked this website and there is no pricing or parts department. I sent a email requesting info on where to buy but not reply so far. The battery cage is needed to build this quadcopter because it is the main frame,battery cage and the mount for the control board. Without it everything would just be floating around the inside of the shell. It is much different than the F180. I seen the H6D has the frame as well but I don't know if it is the same as the H6C because of the FPV camera board inside. Anyway thanks for your input.

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  2. Hi. Great review, thank you.

    Please could you elaborate on how you are achieving 15 minute recharge times?

    Have you completely done away with the supplied usb adapter and if so I don't understand what you're using to connect the battery adaptor.

    Thanks again.

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    Replies
    1. I use a 4.2V 500mA adapter ("Adaptor"?) made for an RC coaxial helicopter. Look at the ones made for Syma. I'm sure that other brands are available as well, a lot of 4.2 power supplies ('bricks') have the same type of battery connection.

      This might shorten the battery life - especially if charged immediately after a discharge, while warm - but they are pretty cheap and time is more expensive.

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  3. need help what could be the problem with cam not doing video but can take pic?

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  4. Hi there, I've got a similar drone. Not on the outside, but on the inside. I'm currently struggling to find any doc on the camera SoC…
    For me the 3 wires are Black/White/Red.
    The signal wire is pulled :
    * 230~320ms for a picture
    * 610~710ms for a video
    (I dont have a numeric spectrometer so I used my phone camera for this…)
    Anyway, the Soc reference is here "BD8A534". No info on the net.
    The SPI small chip is "BoyaMic 25q40ASOI" > Wow, not a chinese fake BergMic ;)
    I may write a blog article on what info I got someday, if you're interested !

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