Eric Bogatin, Signal Integrity Journal Technical Editor
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Eric Bogatin is Technical Editor at Signal Integrity Journal and the Dean of the Teledyne LeCroy Signal Integrity Academy. Additionally, he is an Adjunct Professor at the University of Colorado - Boulder in the ECEE Dept. Eric improves the signal to noise ratio by sorting through all of the information available and finding the best quality content to publish on

Signal Integrity

Finally, an Augmented Reality App That is Not Just Cool but Useful

April 21, 2020

Augmented reality (AR) apps on your phone skyrocketed into popularity with Pokémon Go in the summer of 2016. Today, there are more than two dozen popular AR apps, mostly as games. Recently, inspectAR introduced an AR app for your phone and PC that every electrical engineer will want.

Here’s the dilemma every hardware engineer faces at one time or another. Your new circuit board just came back from the assembly shop, you turn it on, and it doesn’t work. You have to debug it to find the root cause of the bug(s). How are you going to do this?

You have a plan to methodically search through the “usual suspects” but you have three hundred nets on the board with multiple power rails and unlabeled ground pads. How do you find the location of probe-able pads on the top or bottom layers for the clock lines, the power lines, the I2C bus lines and the UART lines?

You pull up the schematic on one screen of your computer and the layout on another screen. Step by step, you trace a net in the schematic and find it in the layout, then zoom in on the layout screen and try to match the pad you find on the screen to the specific pad on your board.

With 64 pins on that QFP, you have to be careful to count the 7th from the bottom lead to probe the clock line, or was it the 7th from the top lead for the local ground reference? You go back and forth between the layout and your board, maybe under a magnifier to find the pad to probe. And if you glance away from your board, you lose focus and have to start your count all over again.

Debugging a circuit board you are familiar with is a challenge. Square this challenge if it is a board you didn’t design but inherited.

inspectAR, a small start-up of eight veteran hardware designers and entrepreneurs headquartered in San Francisco, CA, wants to change this paradigm.  

Their tool, also called inspectAR, creates an AR overlay on top of your board with selected net routing information displayed. You can use a smart phone or a webcam on your computer to view your board in real time and the AR overlay. An example of a typical screen is shown in Figure 1.

Figure 1. The actual screen view of a commerical board showing the specific nets highlight in the overlay.

After a little camera calibration, inspectAR will match the camera view of your board with the layout database you provide. Move the board around, tilt it, rotate it and the image processing algorithm will track the board and automatically adjust the overlay. The tool can natively read Gerber files and Eagle databases. Integrations for other EDA tools are being developed.

You scroll down the list of nets, select a few and the traces or just the pads are highlighted on top of the image of the board. The highlighted overlay is your guide to inspect or probe the board.

It’s always a challenge trying to find an adjacent ground pad close to the signal pad to probe. Just search on ground net pads and you see highlighted all the ground pads, as shown in Figure 2.

Figure 2.  An example of an overlay showing all the ground pads on the board.

Mihir Shah, one of the founders of inspectAR says, “This will change the way you interact with your circuit boards. AR will dramatically reduce your test, bring up and validation time by eliminating many of the tedious steps.” He goes on to suggest, “This will be great for new product introduction. It will mean faster time to characterize the important signals.”

But this is only the beginning. Shah says they want to incorporate optical inspection. With the right database, there would be no need for multiple golden boards to use as a reference. A future direction might be integrating IR cameras with AR to instantly identify specific nets or components running too hot.

Once you pinpoint a net to probe, it’s a logical step, he says, to add a pop-up window with either the live scope trace or a picture or recording of the expected scope trace.

Commercial versions of the tool run on Android and Apple smart phones and tablets, and iOS or windows computers using external webcams. A free version is available for smart phones.

 “Engineers don’t really get it until they see it,” Shah says. To try out this AR tool on your smart phone, download the free version preinstalled with more than 50 open source boards.

To practice with the free mobile AR app, you don't even need a real board. Just open up the product page of any of the installed open source boards, and the AR overlay can appear on the image in your camera phone of the screen image of the board.

While you won’t find any Pokémon’s in these AR views of your board, it may help you find the real bugs hidden among the traces and components.

Through the end of June, inspectAR is offering free access to all students, professors and researchers. Check out this program here. For more information, visit their web site,


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