The Tech Blog

Cool Camera Tech: Folded Optics

Posted under Product Design, Technology on January 1st, 2023 by Amaldev

Earlier this week, LG Innotek launched some cool new camera tech ahead of CES. It’s an optical telephoto zoom lens module for smartphones which can provide continuous optical zoom from 4x-9x magnification. To understand why this is exciting you need to understand how most smartphones currently take zoom pics. Most phones nowadays come with multiple cameras with multiple fixed focal lengths(Distance from the lens to the image sensor). Now when you pinch and zoom on your screen, the camera app switches between these multiple cameras which gives you a zoomed-in view. That’s why you might see a slight jerk when you do continuous zoom. Camera apps have become smart to kind of seamlessly switch between cameras and it fills switch with digital zoom.

This is not true optical zoom. Optical zoom is when you have a lens which can physically move and adjust its distance from the sensor to get a clear image. Now you see the problem, phones are thin and if you need to have true optical zoom you need to have a thick camera module to allow for movement. No one wants that camera bump. That’s where these new Folded optics comes in. Now what LG pulled off is a clever way to bend the light coming from the lens and bend it 90 degrees(with a prism) and arranged the movable lens along the width/length of the phone than the height of it. Now you have wider space to fit everything and pull off excellent zoom images.

I am sure this tech is going to come in the Apple iPhones in a year or two as LG is providing cam modules to iPhones. After a lot of searching, I found that folded optics was patented by Apple, so I have a feeling this was Apple probably licensing their patent to LG to enable the creation of the camera modules with true zoom and to have it thin, to remove the camera bump on future iPhones(Or a collab effort from both teams). Check out the patent US20210026117A1. Oppo showed off something similar last year but is yet to come on a phone yet. It’s a serious engineering effort to pull this off optically & mechanically to make those lenses move at a 1-micron precision.

Happy New Year!

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Back to Basics – Watchdog Timers(WDTs)

Posted under Back to Basics, Educational, Technology on December 25th, 2022 by Amaldev

WDTs are probably one of the most skipped sections in an embedded system because a first-time firmware engineer firmly believes that the code that they wrote is 100% bug-free. Somehow they feel that it’s not needed because they have put the code through tons of testing and still couldn’t crash the firmware. Seasoned folks will tell you that this is absolutely wrong, users on the field will definitely find ways to break your system. WDTs are an absolute necessity for anything which you ship out.

So what are they basically? A WDT is a type of timer that is used to detect and recover from system hangs. It works by continuously monitoring the system and resetting itself after a certain period of time. If the system fails to reset the timer(meaning it has gotten stuck somewhere) before it expires, the WDT will trigger a system reset or other recovery action. It’s analogous to you petting a dog at a constant interval and the moment you stop or miss the petting, the dog will bark/bite to alert you. Hence the name “Watchdog”.

There are diff variations of WDT. Internal WDTs are something which you find commonly in new-age controllers wherein a certain section on the chip is a dedicated timer to perform the WDT. External WDT variant usually utilises an external chip to perform the same. The general consensus is that for anything mission-critical you use an External WDT, just avoid the hardware locking up in some extremely brutal edge cases if you can afford to have that extra part. WDTs in general are not only used for a hard reset, sometimes can be multi-staged wherein you can trigger Action#1 when Timer#1 runs out via interrupts and so on and give the system to correct it and the last one being a hard reset. Some internal WDTs can be used to trigger an interrupt and then give certain processing clock cycles so that some debug state info can be saved before issuing a hard reset.

It’s an understatement to mention that WDTs are essential. NASA Clementine moon spacecraft in 1994 was a casualty of badly implemented WDT in software whereas Mars Pathfinder had a well-built WDT which saved millions of dollars.

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