Tech Tuesday – Anatomy Of A Professional Vehicle Camera System: Accelerometers
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Tech Tuesday – Anatomy Of A Professional Vehicle Camera System: Accelerometers

We are surrounded by devices that use accelerometers. The most well-known are in modern smartphones, but they can be found in everything from hard disks to cars and cutting-edge robotics technology. They allow the devices to do everything from the simple to the incredibly complex.

They are not magic, but what they allow devices to do seems like it. So, let’s take a look at what an accelerometer is and how it works.

The History Of Accelerometers
The name is quite misleading because accelerometers measure much more than just acceleration. In fact for very specialised applications they can measure up to 13 axes. This allows modern devices like smart watches to detect very fine movements and gestures that can then be linked to specific actions.

However, like all things that today are almost microscopic, the origins of the accelerometer was more big-tech than hi-tech! In fact the first accelerometer was created back in 1783 by George Atwood. Atwood’s device measured linear acceleration, but it’s not clear what is was invented for back then. It wasn’t until 1923 when the accelerometer had evolved into a ‘tiny’ 1Lb device made of multiple carbon disks in an E-shaped frame and measuring ¾” x 1-7/8” x 8-1/2”. It was used in bridges, dynamometers, and aircraft; and measured forward and side-to-side motion and stresses.

Modern accelerometers are indeed tiny and fit into the smallest of modern devices. They don’t even use moving parts, but instead use various mechanisms, such as piezo-electric, capacitive and even thermal technology to measure tiny fluctuations in movement and angle.

What Do Accelerometers Do?

Let’s look at the most modern uses for accelerometers:

  1. Mobile Phones
    The simplest use is to detect when the phone is picked up and put down. The action of picking the device up and holding it vertically creates an acceleration and angular force, which can be interpreted to mean you want to look at the screen. The boffins therefore program it so that when you do this, the screen turns on…cool!But it can also be used for everything from playing motion-based games to looking at 360-degree pictures on Facebook.
  2. Laptop Hard Disks
    In the old days (by that I mean the 90s!) when a laptop was turned on, you had to treat it like a desktop. If you moved it and banged it on a table or, God forbid, you dropped it, you could kiss your hard disk, and all your data, goodbye. Modern hard disks use accelerometers to detect when the laptop is lifted and moved, or dropped, and then instantly park the hard disk’s reading heads. This means that you can be quite rough with a laptop and lose no data.
  3. Cars
    The airbags in cars are triggered by 2-axis accelerometers (as they simply need to detect excessive forces in the horizontal axis). So a hard deceleration that is then followed by a hard stop triggers the airbag to deploy before you even start to move forwards!
  4. Fleet Tracking and Telematics Systems
    For many years, fleet managers have wanted to get more data about how their vehicles are being driven. Are drivers driving well or accelerating and decelerating too much? Smooth driving means less fuel wastage, so being able to measure this is a big bonus. Driver safety is also a factor, so knowing the moment an accident happens allows the fleet manager to take all appropriate actions.

ProVision Systems Use Advanced 3-Axis Accelerometers

3 axes allow you to measure forward/back, left/right and up/down movement. This is really important to understand braking events, harsh driving, such as heavy lean caused by too much speed around corners and obviously hard acceleration and braking. But the vertical Y-Axis can also measure if they drive over deep potholes or too-fast over speed bumps, which could cause damage that then needs maintenance attention.

The device itself uses a small chamber of gas that is heated. Because temperature rises, the gas at the top of the chip is hotter than at the bottom. There are multiple temperature sensors that then measure the temperature at these fixed points. So, if the device is level, wherever the gas rises evenly to the top and that is therefore ‘up’. As the device moves, the gas does too and the hotter gas can be measured in different areas. OK, to simplify that a bit, imagine that it was water instead of gas and the water sloshes about inside and is measured by sensors. It’s basically the same technique, just smaller and lighter.

Because every vehicle is different, one of the key factors of ProVision’s professional installation is to log the physical position of the main DVR relative to the ground. This is because the device can be fitted horizontally or vertically and sometimes even upside down. By logging how it is installed, we can then properly report on the forces being applied, so you receive the right alerts for each type of event.


The tiny, yet mighty, accelerometer has revolutionised how we interact with technology and the information IoT (Internet of Things) devices can provide us. It’s just one of the amazing pieces of technology carefully selected and installed in all our vehicle camera and tracking systems.

If you are looking for cameras or full vehicle CCTV solutions, ProVision has the solution for you. Give us a call to find out more.