Teardown Tuesday: Micro Drone

What's inside of a hand-sized micro drone? Find out in this Teardown Tuesday!

Drones are cheaper and more popular than ever! They are sold everywhere from Walmart to Amazon, ranging from thousands of dollars to as little as $10.

In this Teardown Tuesday, we are going to take a look at a relatively inexpensive micro-sized drone that fits in the palm of your hand.


Image courtesy of Amazon.

Overview

Some drones are packed with GPS, cameras, and barometers. The drone in this teardown is a relatively basic one that is primarily designed for indoor use (due to its size). It's a Cheerson CX-10 and it was purchased for around $14 USD.

The Micro drone
The micro drone

To open this drone, four small Phillips head screws needed to be removed. The plastic shell of the drone was also clipped together.

The Screws Holding the Drone Together
The small screws holding the drone together

Circuit Board


The Top of the drone PCB
The top of the electronics

In this drone, the PCB also acts as part of its structure.
The board is two layers with surface mounted components on each. There is blue solder mask on both sides of the PCB and white silkscreen on the bottom of the board. The board is entirely comprised of surface mount components. The wires from the four small DC motors and the single cell lithium battery appear to be hand-soldered.

The Bottom of the drone PCB
The bottom of the electronics

Microcontroller


The ARM drone controller
The Cortex-M0 microcontroller

The brain of this drone is an STMicroelectronic STM32F031K4 ARM Cortex-M0-based microcontroller in a 5x5 mm UFQFPN 32-pin package. This microcontroller has a max clock speed of 48Mhz, 32KB of program memory, and supports a variety of communication protocols such as I²C, SPI, and UART.

Radio


The drone transceiver 2.4ghz
The 2.4Ghz transceiver

In order to receive data from the handheld radio transmitter, a receiver is used. This is a 2.4GHz transceiver part number XN297. This transceiver communicates to the microcontroller through an SPI bus. The XN297 appears to be a clone of Nordic Semiconductor’s popular nRF24L01 2.4GHz transceiver. On the back side of the PCB, there is a trace antenna.

The trace antenna on the drone
The trace antenna

Sensors


The sensors on the drone PCB
The gyroscope and accelerometer

To ensure that the drone is stable and easy to fly, an accelerometer and gyroscope are used. This drone uses an Invensense MPU-6052C that contains a 3-axis gyroscope and a 3-axis accelerometer in a single package. This sensor communicates to the ST microcontroller through I2C bus.

Battery


A 100mAH drone battery
The li-ion battery

In order to give this drone a few minutes of fight time (around 5 minutes per charge), a small single cell Li-Ion battery is used.

The battery used in this drone has a nominal voltage of 3.7v and a listed capacity of 100mAh, giving it 0.37 W/hr of energy storage. This battery is manufactured by Shida Battery Technology Co., Ltd. and, based on dimensions, appears to be part SDL701717P. This battery measures approximately 17mm x 17mm x 7mm.

Additionally, this battery contains a small protection circuit board to prevent over-discharge. To provide stable voltage to the drone, a low drop voltage regulator is used—part LN1134, manufactured by Shanghai Natlinear Electronics Co. This regulator, in an SOT23-5 package, can provide 300mA at 3.0V.

drone voltage regulator
The 3.0V LDO regulator

Wrapping it up

At around $14, this drone is packed full of a lot of electronics. If similar parts were sourced and assembled domestically (even in quantity), the profit margin on this product would be nonexistent. These drones are most likely made in quantities of 10 or 100 thousand in order to be sold at such a low price.

Only a few years ago, similar small and simple RC helicopters were selling for $35. It will be interesting to see the future of toys as the cost of electronics decreases.


Thanks for taking a look at this Teardown Tuesday! Stop by next week for another teardown!
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Hi, I`m Sostenes, Electrical Technician and PLC`S Programmer.
Everyday I`m exploring the world of Electrical to find better solution for Automation. I believe everyday can become a Electrician with the right learning materials.
My goal with BLOG is to help you learn Electrical.
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