Teardown Tuesday: Dash Camera
Dash Cameras are becoming a very popular automotive accessory. What's inside of one?
Dash Cameras are becoming a very popular automotive accessory. What's inside of one?
A few years ago compact windshield-mounted cameras, often referred to as dash cameras, were once used exclusively by law enforcement. Today they are becoming popular as a way to provide the driver evidence in the case of a crash or alleged traffic infraction. In this Teardown Tuesday, we are going take a look at what makes a dash camera suited for its application. We are going to tear down a BlackSys CH-100B provided by BlackboxMyCar.
The BlackSys CH-100B Dash camera
Dash Cameras differ a lot when compared to action cameras or other types of video cameras. The design of many dash cameras has been specially geared toward the application and the operating environment.
The rear of the BlackSys Camera
Temperature Range - The range of temperatures that a dash camera can be exposed to is huge. The interior temperatures of a car can reach 140*F, but also reach freezing temperatures. Many consumer electronics are not designed for temperature ranges that wide. Dash cameras need to contain electrical components that are rated for those temperatures.
Dash Cameras are Designed to be Exposed to the Hot Summer Sun
Loop Recording - Loop recording is a key feature found on dash cameras. Loop recording will overwrite older videos on the memory card with new ones once the storage is full. In addition to loop recording, the video needs to be saved rapidly so the video recording has minimal interruptions.
Loop Recording - Courtesy of Philips
Sensors - Dash cameras often have sensors that normal video cameras don’t have. Dash cameras often contain accelerometers to detect an impact on a car, motion sensors that use the camera sensor, and GPS to recorded the speed of the vehicle.
GPS and Accelerometer Data from the Cammsys App
Dash cameras are relatively easy to install. The camera itself is typically held in place with a high strength adhesive such as 3M VHB or a strong suction cup mechanism. In the case of the Blacksys CH-100B a strong adhesive is included.
The 3M Adhesive Used to Mount the Dash Camera
Connecting the dash camera into the car’s electrical system can be done two ways. The first way is to simply plug into the 12v outlet in the car. This provides power to the dash camera when the car is powered on.
The Dash Camera can be Powered From the 12v Outlet
The second way to install a dash camera is to attach it to the fuse box. The Blacksys CH-100B has the ability to remained turned on while the car is powered off. To achieve this, the camera needs to be wired into a fuse that is always on, and into a fuse that is powered on and off with the car. As a safety measure, the camera monitors the voltage of the car battery and automatically powers down when the battery reaches a preset cut-off voltage.
A Dash Camera Wired to a Fuse Box
The Massive Capacitor. 5 Farads.
Let's start with the largest component inside of the BlackSys camera, the capacitor! The dash camera uses a large capacitor to withstand power fluctuations and save the video file when the power is removed from the camera. The large electrolytic capacitor is often called a super cap. This capacitor has a capacitance of 5.0F and is rated for 5.4V. The Ropla capacitor has a temperature rating of -40°C to 65°C. This extended temperature range is one of the major reasons why super-capacitors are often used in dash cameras as a better alternative to Lithium-Ion batteries. This particular capacitor is made by Ropla.
The Ti SOC That Runs the Dash Camera
At the heart of the dash camera is a TI DaVinci DM385 that contains an ARM Cortex-A8 Core. This is a high-performance SOC that is designed for applications just like this. TI’s datasheet specifies that this SOC could be used in “All Camera Applications”. This SOC handles everything from the on-screen display (OSD), encoding the video, USB, Ethernet, ect. Take a look at page 1 and 2 of the datasheet for a list of many of the features of this SOC.
The 4GB of DDR3 RAM
Attached to the processor are two matching IC’s. These IC’s are DDR3 RAM made my Micron Technology, part number MT41K128M16JT-125:K. These are 2GB each and run at 800Mhz.
The Serializer and Deserializer IC
Also paired to the DaVinci SOC is a TI DS90UB914Q-Q1. This IC is a 48 pin 10 or 12 bit Serializer and Deserializer. A quick note, the IC has a National Semiconductor Logo on it, in 2011, TI acquired them.
The Lens of the Camera
The camera on this dash camera is a 2.1 megapixel Sony sensor. This camera has a fixed lens that has a 135° viewing angle.
The Fixed Focus Camera Lens on a Sony Sensor
The camera is connected to the circuit board through a flat cable. Surrounding the cable is metal shielding to reduce the effects of noise on the video.
The Shielded Cable
The USB WiFi Dongle
Instead of having a built-in WiFi radio, the BlackSys dash camera uses a USB WiFi dongle. The dongle is part CF-WU715N, made by COMFAST. This WiFI dongle uses a MediaTek RT5370 IC for all of the WiFi functionality.
Real Time Clock
The Real Time Clock IC and Crystal
To maintain an accurate data and time this dash camera uses a real-time clock IC. In the image above, that is the IC labeled "1339". This a DS1339 I2C serial real-time clock manufactured by Maxim Integrated. This IC has a lot of functionality including programmed leap years until 2100, the ability to run on a backup battery, day of the week memory, and even time of day alarm. For more information on this IC, take a look at the datasheet. Also in the image above labeled CB319, to the left of the real-time clock, is the crystal oscillator for the RTC. This is a 32.7680KHZ crystal that is commonly found paired to RTC's.
The Real Time Clock Battery
To keep the real time clock up to date, a small 5.5mAh lithium coin cell battery is used. This small battery exclusively powers the real time clock on the dash camera. When the RTC is running off of the battery, it requires 550nA (at room temperature). Based off of the capacity of the battery and current draw, the dash camera can remain powered off for 10,000 hours (416 days (assuming no other losses) and maintain accurate time.
Four of the Power Supplies are Visible in this Image
The dash camera contains 5 separate step-down voltage regulators. In the picture above, 4 of them can be seen. In the center of the Image are two TI TPS5432 step down converters. These step-down voltage regulators have buck topology and a built-in switching FET that can provide up to 3A.
One of the AP2420 Buck Voltage Regulators
Also in this dash camera are two step-down regulators that are labeled as "AP2420" and "1506". This exact device could not be found, but the BM1703 is listed as "Pin to Pin [Compatiable]". According to the datasheet, these are 2 amp buck regulators that require minimal external components. Also, the microphone can be seen in the image above, labeled as M1.
U32: The Primary Voltage Regulator of the Camera
The primary voltage regulator of the camera can be seen in the image above. This is a Eutech EUP3484 buck voltage regulator. This voltage regulator takes in the 12V from the vehicle and converts it down to 5v to operate the camera. The 5V is then converted to other voltages by the four other voltage regulators. The inductor, input capacitor, and output capacitor for the voltage regulator can also be seen in the image above.
The Micron Flash Memory
In addition to the Micron RAM inside of this camera, there is also a Micron Flash Memory IC. This is labeled as U4 in the image above. This memory IC is part number MT29F2G16ABBEAH4. This is a 2GB flash memory chip.
The Audio Codec and Speaker Amplifier
This dash camera also features a speaker to communicate information to the user. The internal speaker can not be directly powered by the TI SOC so an external amplifier is needed. The dash camera uses a TI TLV320AIC3110 audio codec with a 1.3W speaker amplifier.
This dash camera features many high-quality, name-brand components. The main SOC made by Texas Instruments is quite powerful and is suited well for this application. Right now, the dash camera market is flooded with a variety of different camera choices, ranging from cameras that can be purchased for less than $20 to more expensive models that offer better video quality, higher quality components, and better build quality. This dash camera, a Blacksys CH-100B, is highly reviewed and is considered a quality dash camera. A big thank you to BlackboxMyCar.com for lending a unit and making this Teardown possible!
Thanks for looking at this week's Teardown Tuesday.
Stop by next Tuesday for another teardown! We're always looking for new things to teardown, if you have any suggestions or would like to contribute an item for a future Teardown Tuesday, click here for my email address.
As an added bonus to this week's teardown. Here is an inside look at the rear dash camera that is part of the Blacksys CH-100B system.
The Rear Camera
The Front of the Rear Camera PCB
The Back of the Rear Camera PCB
Next Teardown: Fitbit Charge Fitness Tracker