How to design a camera:
A guide in selecting components in camera design

by | SLIMDESIGN | Last updated : Sep 21, 2021

We often get asked what the development of consumer electronics entails. To give an insight into this, we have taken the development of a camera as an example to show the different steps and expertise needed. In this article, we will give a summary of all decisions that need to be made in the component selection process for the development of a camera.

At SLIMDESIGN we know one of the most critical parts of the product development process is the selection of the right components for your product. This is why we already start with pre-selecting components in an early stage, right after all product requirements and features are determined. The selection of parts doesn’t just determine critical factors in your product’s final specifications and price, e.g. a faster but more expensive motor makes your car go faster, but additionally has a huge impact on product design, supply chain management, and level of innovation.

Selecting components just based on the requirements will always lead to contradicting outcomes. We all want the highest specifications, in the smallest form factor, for the lowest price. To combat these contradictions, we work with our design methodology. In which we have developed an integrated, lean, development process that allows design, mechanical, software, and electrical engineering to be seamlessly interwoven.

Selecting the right components is a custom job, and unique to each product design process. To give you a bit more insight into some of the aspects that come into play when selecting your components, we’ve taken the design of a camera as an example. In this article, we’ll show you which components you would need, and what tradeoffs they cause in your final product.

Camera development is an example of a project in which you’ll need a dedicated project team. This ensures you can be more efficient, flexible, and faster than traditional methods, without the loss of information during the process. To streamline this, we make use of the specification loop, to review and validate which requirements are a priority and how they affect each other. With this method, we protect the project against surprises that are difficult to change or solve at a later stage.

Processing modules

Every IoT device needs a combination of processor, memory, video encoder/decoder, and additional chips. ); These are technically spoken the brains of your device. Here is where the first decision on requirements has to be made. You can develop and source these components separate or select everything combined in a SOM (system on a module), SOC (system on a chip), or SIP (system in a package).

So when to choose which? The SOM is interchangeable, easier, and faster to integrate on a PCB. But, more expensive and larger. The SIP is a package of modules with everything packed and stacked together where the SOC is a one-level chip with all components integrated that can be soldered directly to the PCB

For most of the packages from the larger companies like Qualcomm or Ambarella, you need large order quantities (100K) to even be able to order and get the right amount of development support. If your order quantities don’t suffice, it might be easier to get third-party systems including their SDK (software developer kit). This lowers the development time and cost but comes at a higher part price.

Most important for the selection of each of these is the availability of a complete SDK and an evaluation kit, in combination with the right level of documentation. Especially at the beginning of your project, when a lot of the requirements might still be undefined. It helps to kickstart the development because you can start testing and reviewing these requirements directly with working prototypes, instead of losing time and resources with designing, developing, and producing a PCB and accompanying software from scratch.

Image quality

The requirements for the image quality can be defined depending on the use-case for the camera you are designing. Making sure these requirements are determined and set beforehand ensures you won’t lose time in the process later on. Image quality is a collective term and consists of image resolution, frame rate, possibly night vision, field of view, and lens distortion. These choices made on these also have a big impact on the other hardware like; chipset, memory, power consumption, and cost.

So to determine these requirements, ask yourself the following questions.

  • Image resolution: The number of pixels you want to show in your final image, do you really need a higher resolution for your application?
  • Frame rate: How many frames per second do you want to show?
  • Night vision: Do you need your camera to be able to shoot in the dark, and if so, how good does this night vision image need to look?
  • Field of view: Do you want your camera to be able to shoot a wide-angle shot? Are you going to fil objects far away or close by? Or both?
  • Lens distortion: How much effect may the lens have on my final image? Is it necessary to have all straight lines in an image appear to be straight?

Image sensor

Based on the requirements you’ve selected above, you can now investigate what kind of image sensor would fit your needs. Nowadays, most consumer products use CMOS sensors. These are available from 3 main brands SonyOmnivision, and Onsemicon (formally known as Aptina). The challenge here is to find a sensor that fits your application. The number of pixels, framerate, and pixel size are the most important criteria. In our experience, the sensors from Onsemicon suit most of our applications for a reasonable price.

 

Optics

With the sensor size, resolution, and FOV the lens selected, you can now focus on the optics part of your camera. These days it’s very common to buy camera modules, which are a combination of the sensor and optics in one module.  But your project might have specific needs. You might need an ultra-wide-angle or a very low total length. We always select a couple of lenses from different suppliers and test them with the first working prototype. To make this work; hardware, mechanical, and software engineers need to work seamlessly together. But seeing the first image from a prototype pop-up on your screen always gives a great sense of accomplishment!

Night vision

When night vision is required, IR LEDs and an IR-Cut switch are good possible solutions. Because of the IR-cut filter, you have colorful images during the day and high contrast low color images in low light situations. Another possibility for night vision is to select a very light-sensitive sensor with backside illumination and a high dynamic range. This gives quite nice colorful footage also during low light situations but with less contrast compared to IR LEDs.

Wireless connectivity

Recording high-quality footage to the internal memory or sd-card is a standard function of most of the camera solutions we develop. But often there is a request to stream the video via wifi or the cellular network to the cloud and/or other devices. In other use-cases, Bluetooth connectivity might be required. As stated at the beginning of this article, sometimes these features are integrated into the processing module, but often you need separate wifi and or cellular module to add these functionalities. These modules are widely available in plenty of variations. To decrease development time and risk it is important to select pre-certified modules which preferably come with a developer kit and/or an SDK.

Antenna integration

Every different radio/wireless connection needs one or more antennas. Depending on the frequencies and technology these are very small ceramic components on the PCB or large rubber antennas on top of the device. There are a couple of main rules when designing with antennas; bigger is better and make sure they are positioned as far as possible from each other, and highly sensitive and high-speed components. Often the antenna’s integration starts late in the design process which might result in low antenna and connectivity performance. This will lead to higher transmitting and battery power usage and lowers user experience. That’s why you should try to integrate all the antenna’s from an early stage. At SLIMDESIGN we simulate and prototype the antenna’s together with our antenna specialists in the design to validate the locations before we make the first integrated working prototype. To make sure the performance suits the requirements.

Thermal optimization

When all functions of a 4g live streaming camera are activated it consumes up to 5 watts of power and creates a lot of heat. For some components, it is no problem to run at 60+ °c but others need to stay as cold as possible. For example, the CMOS image sensor will create a lot of noise when the temperature rises above 40 °c, and the lifetime of lipo batteries degrades much faster at higher temperatures. Additionally to these technical aspects of temperature, users who touch temperatures above 48 °c on metal surfaces experience pain.

To manage the temperature inside of you can do a thermal analysis of the camera, and based on this optimize the materials and design to minimize the risk of overheating. When you use thermal flow analyses software, all optimizations can directly be compared simultaneously to reduce the development time.

Water resistance

Water-resistance sometimes seems to be just another requirement but the impact on the design and engineering are significant. When you want to make a device watertight, the first step is to determine how watertight does the product need to be. The most common way of rating water-tightness is the IP-ratings table as shown in the images. Starting at the lowest level of IP-x1, every step closer to IP-x9 becomes increasingly difficult from an engineering point of view. The impact of each higher level of water-tightness on the enclosure with all connections, buttons, and seals becomes more challenging. Even though there are multiple proven methods for creating waterthight seals, you will always need to prototype and test these solutions. To make sure the device passes the IP certification we normally use our test methods at the studio. When we are confident in the solution proposed, we use a unified body test lab for the certification.

 

Certification

Every physical product needs to be as safe as possible for the user and environment. Before you start with the development, discuss and define the target market to make sure you don’t miss important legal requirements. This is not the fun part of product development but the impact on getting your product to market as quickly as possible when you don’t do this is high! Depending on the target market and the used technologies there are specific regulations you must comply to. Some are based on the region like the CE for Europe and FCC for the USA. Others are based on technology requirements. When you have a radio with antennas in the device you need FCC certification and when you want to use for example the BlueTooth or WiFi icon you need dedicated certification. There are also many certifications based on customer preferences like IP water resistance, military mil-spec, or Atex explosion-proof.

There will never be a perfect component.

As you can see in the article stated above, choosing the right component for a product like a camera will always be a trade-off. Especially in these days of chip shortage, which will increase the lead time and price on many of your desired components, finding a component that fits your requirements, budget and schedule is a very specific job. This will require you to choose between these factors based on the amount of risk they are for your project. Even with our years of experience, a global network of trusted suppliers, and component-based design methodology, it sometimes still is hard to find the ideal component.

Want to know more about our production support services, or one of our other design services? Please contact us, or request a free design consult.

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