Action Camera Teardown

2018-02-13 | By All About Circuits

License: See Original Project Capacitors Resistors Wireless

Courtesy of All About Circuits

Action cameras are becoming hugely popular. You can find them in many different environments, including Airsoft, dashboard cameras, sports, and drones. In this teardown, we will see how they’re are put together and try to identify some of the internal components.

The Function Buttons and Battery

The camera shown in this teardown, the Lightdow, is a near copy of the famous GoPro camera. The front of the camera has the on/mode button and the lens, the top has an "OK" button, the side contains two volume control buttons, the back has a screen, and the other side has all the IO connectors.

The front of the action camera

The screen on the back

Volume control buttons

IO connectors on the side of the camera

The battery compartment is located on the bottom side, and a small sliding latch removes the cover. Once removed, the battery can be lifted out with the aid of a small material tab. There are no mechanical parts keeping the battery in place, aside from the metal contacts that slide into the battery connectors.

The battery and camera

Getting Internal Access

Getting access to the internal parts can be somewhat difficult for two reasons. First, the camera is incredibly compact, and secondly, the back display protector (which is stuck on) needs to be pulled off in order to gain access to the screws on the other side. This is a teardown, so these tasks are easy, but had this been a repair, this would have been quite the challenge! So, first, I pried the front face off the main camera with a flat-tip screwdriver.

Front face removed revealing the on/mode button

Removing the next cover involves extracting multiple small screws, two of which are hidden. The first screw can be found hiding under the white circular sticker. In order to reach the other screw, I had to remove the black plastic ring that sits around the lens. With the screws removed, the camera is very quick to come apart.

With the small screws removed, the camera is easy to disassemble

However, before we can get the PCB and other parts out, we still need to remove the back cover. First, I used a very small screwdriver to peel off the rigid screen protector, and then I could extract and remove the display.

The screen protector removed

The camera screen removed

After unscrewing six small screws from the back of the PCB, the battery compartment and lens cover could finally be removed.

Close up of back showing some screws

The PCB Top Side

With the camera parts spread out, a few parts stand out immediately. There are three external PCBs that house components, including buttons and ICs, a microphone, some large ICs, and an image sensor.

The camera laid out

The first component of interest is the image sensor. In order to removing the lens system and reveal the sensor, two screws on the underside of the PCB must be removed. This sensor is responsible for detecting images, which are then converted into still pictures or a video stream. Such technology usually requires rather beefy MPUs, so the processor in this device will have at least a capacity of 50mbps, unless there is some dedicated hardware for directly storing captured images. The camera claims to have a 4K resolution, but there is a chance that this sensor is not 4K. Instead, it may use pixel interpolation to give the impression of 4K.

Close-up of the CMOS sensor

Below the sensors are two large ICs, one rectangular and one square. The square chip has the identification "NOVATEX NT96660BG", which, according to some online research, is a video SoC that has many features, including:

• 32-bit CPU (MIPS32)
• 16 KB instruction and 16 KB cache
• Operating speed up to 432 MHz
• 16-bit DDR2/DDR3 SDRAM bus
• Up to 50-megapixel image sensor
• Sensor interface engine
• Image processing engine
• Face detection
• Image stabilizer
• Video output (PAL, NTSC)

However, online resources also suggest that the maximum resolution this device can output during video is 2880 by 2160 at 24 fps, which implies this device is not true 4K. Instead, it is stretched or interpolated.

The main SoC (centre)

The second large IC on the top side has the identification "5EK77 D9PRP", which does not return any results online. However, considering its proximity to the SoC and the large amount of memory needed for video streaming, it’s safe to assume that it is a SDRAM IC that provides RAM for video capture, which is then sent to the SD card for permanent storage.

The possible SDRAM IC

Other components on the top side include resistors, capacitors, diodes, and possibly even some discrete transistors. Most of these parts are found around the microphone input, which suggests they are designed for handling audio signals from the microphone. The other large ICs have several ceramic capacitors around them, which serve two main purposes: EM spike suppression on the power rails and ensure smooth power to those devices. I can also spot some neat meandering traces, which are done for a number of reasons. Meandering traces can help with impedance matching, which reduces reflections on conductors (signal bounce back). They can help make precision resistances, and signal delays can be introduced with longer traces.

Various components and meandering traces

PCB Underside

The underside of the PCB is a lot less interesting than the top side; however, the bottom side is littered with surface mount components, several clock crystals (suspected to be 32.768 kHz), various ICs, the SD card reader, and the display connector. The underside shows many stitching vias, which are used to prevent unwanted signals leaving and entering the device. By connecting power planes on multiple sides using stitching vias, the resulting effect is similar to a Faraday cage where stray EM waves get absorbed. This is imperative for any device that is on the market because there are strict laws about EM emissions (think FCC and CE).

The underside of the main PCB

One small IC (located in the bottom right) has the identification "25Q32", which is a 32 Mb SPI flash IC. This device remembers configuration data, wireless networks, and various other pieces of information that the device needs to configure.

The SPI flash IC (bottom right)

Another smaller IC had an identification that could not be fully identified (at least with any online documentation), so its purpose of this is somewhat of a mystery.

The mystery part!

Wireless Controller

The last IC of interest is found on an external PCB, which has the identification "8189ETV". Before I looked up the IC, it was obvious what this device was: a RealTex wireless module that handles 2.4 GHz transmission using 802.11 bgn. Of course, searching the device online reveals just that—an integrated wireless network SDIO interface.

The wireless network card PCB

Close-up of the wireless IC

Conclusion

This camera shows many common production considerations, including the use of surface mount devices, using pre-made SoC ICs, stitching vias to help with EMC control, the quest for miniaturization, and the importance of compact design. However, I could argue the biggest lesson to learn here is, if you invent or develop a device, chances are someone else will copy your design, make slight alterations, and steal a portion of the market!

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