EEVblog Electronics Community Forum
Products => Other Equipment & Products => Topic started by: 8086 on November 06, 2014, 05:35:27 pm
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Bought one of these on a whim last Thursday, thought a teardown was in order! What do you get in a £12 mini quadcopter?
(http://i.imgur.com/yAXN4Gq.jpg)
http://www.banggood.com/Cheerson-CX10-CX10-Mini-24G-4CH-6-Axis-LED-RC-Quadcopter-RTF-p-926614.html (http://www.banggood.com/Cheerson-CX10-CX10-Mini-24G-4CH-6-Axis-LED-RC-Quadcopter-RTF-p-926614.html)
It's definitely a neat little toy, and yes it does fly, very well in fact. So of course I was keen to see what's under the hood.
With the rotors removed:
(http://i.imgur.com/e65laYT.jpg)
The underside:
(http://i.imgur.com/zeLxlYK.jpg)
You can see the 100mAh battery, and the four retaining screws.
They look like small machine screws, rather than self tappers.
(http://i.imgur.com/lTMYNiw.jpg)
Well, what do we have here? No chip-on-board epoxy blobs, a few QFN ICs.
(http://i.imgur.com/W52bDU3.jpg)
Top middle, the IC is labelled "XN297", which looks to be the 2.4GHz receiver - a "wireless mouse solution" by a company called Panchip: http://www.panchip.com/en/products_show.aspx?cid=70&id=351 (http://www.panchip.com/en/products_show.aspx?cid=70&id=351)
I assume the controller contains another XN297, I didn't take it apart.
To the left is an Invensense MPU-6050 - an integrated 3 axis gyro and 3 axis accelerometer. Whether it's real or fake is anyone's guess, they seem too expensive to put the real thing in a £12 product. http://www.invensense.com/mems/gyro/mpu6050.html (http://www.invensense.com/mems/gyro/mpu6050.html)
To the right is a STmicro STM32 F050K4 MCU.
There is also an LED in each corner - blue at the front, orange at the back.
Let's flip the board over:
(http://i.imgur.com/sstUMAr.jpg)
To the top is the PCB antenna, coming through from the other side.
Underneath that is a 16MHz crystal.
The 5-pin IC just below the date marking is marked "F04A", which could possibly be a 4.5V threshold detection IC - a really basic battery charge cut off, perhaps. Now I know this is in here, I won't be trusting it while charging anymore. There is no charging IC.
Interestingly, pin 4 of the aforementioned IC isn't actually soldered to the PCB - it's left hanging, over some silkscreen. Not sure what that's about.
Each of the ICs on the four 'arms' is marked "004H", I assume just a simple transistor or something to drive each motor.
The LiPo battery is marked "751517", 3.7V, 100mAh.
Here's a gallery with a few more pictures: http://imgur.com/a/jBN4E (http://imgur.com/a/jBN4E)
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Is that battery swelling so much already? Seems to be close to the point of doing an in air flame out session.
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Is that battery swelling so much already? Seems to be close to the point of doing an in air flame out session.
That's what I thought too, but it looks like it just might be at an odd angle, and not actually puffed at all.
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The battery is about twice as thick as a normal LiPo, and it seems to be intentional. It doesn't seem to have swelled to me.
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There is a giveaway for these (2 units) currently: http://forum.banggood.com/forum-topic-35494.html (http://forum.banggood.com/forum-topic-35494.html)
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Thanks a lot for posting that, I was curious about what's inside these!
[snip]
(http://i.imgur.com/sstUMAr.jpg)
To the top is the PCB antenna, coming through from the other side.
Underneath that is a 16MHz crystal.
The 5-pin IC just below the date marking is marked "F04A", which could possibly be a 4.5V threshold detection IC - a really basic battery charge cut off, perhaps. Now I know this is in here, I won't be trusting it while charging anymore. There is no charging IC.
Interestingly, pin 4 of the aforementioned IC isn't actually soldered to the PCB - it's left hanging, over some silkscreen. Not sure what that's about.
Each of the ICs on the four 'arms' is marked "004H", I assume just a simple transistor or something to drive each motor.
The LiPo battery is marked "751517", 3.7V, 100mAh.
Here's a gallery with a few more pictures: http://imgur.com/a/jBN4E (http://imgur.com/a/jBN4E)
That SOT23-5 part is an LDO, it's needed as the parts on the other side can't operate at above 3.3V. It's the standard pinout of a so23-5 LDO with a bypass pin. The bypass pin can be connected to a small, low-leakage capacitor to ground to improve noise performance. Putting the pin on top of the ground plane with solder mask + silkscreen in-between is a cute idea for a 0-cost capacitor ;)
The charger IC is bound to be inside the charging cable (it makes sense not to carry that around while flying).
The MPU6050 might be a recycled part... I don't think there's actual fakes yet as the manufacturing technology for MEMS gyros is pretty challenging, and it wouldn't fly so great without gyros ;)
You can always learn something interesting from taking apart Chinese toys...