Author Archives: Matthew

Android device encryption hang at Time remaining 00:00

Recently I had a frustrating problem while trying to enable full disk encryption on my Android device (Motorola G3 “osprey”). Every time the encryption process would hang forever at: EncryptingWait while your phone is being encrypted.Time remaining 00:00 After forcibly … Continue reading

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WebEx audio input hang on Linux (Chrome/Chromium bug)

If you have been connecting to WebEx meetings on Linux using Chrome/Chromium versions 79 or 80, you might have run into issues where your microphone randomly stops working and other participants cannot hear you. When trying to reconnect to the … Continue reading

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H field and material boundaries

For a long time I thought of the H field as being generated by free currents only. The problem with this view is that it leads us to make erroneous assumptions. We know from the definition of H that:   … Continue reading

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Magnetic field of a ferrite core solenoid

Consider a solenoid made of wire wrapped around a rod made of iron, ferrite, or other ferromagnetic material: It is well known that the magnetic field will be significantly stronger inside such a solenoid, compared to an air core solenoid. … Continue reading

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Designing and making a ring

Recently I designed an engagement ring for my (now-)fiancĂ©e, from scratch. This was a fascinating and challenging process, and gave me a new appreciation for both the art and engineering of jewellery design. The first step in the process was … Continue reading

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Splines in Onshape, part 2

In this second part of the series, I’ll briefly cover drawing splines directly in 3D, and then discuss offset curves, which are the original reason I started on this long journey delving into Onshape curves. Continue reading

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Splines in Onshape, part 1

In this post I talk about splines and various ways they can be represented, with particular reference to Onshape, a web-based CAD system. Continue reading

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Dell Venue 11 Pro travel keyboard troubleshooting

Introduction I recently purchased a pair of Dell Venue 11 Pro 7140 tablet computers — one for myself and one for my girlfriend. I figured this would be a good crossover device between a tablet and a laptop, and so … Continue reading

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Unlocking my Lenovo laptop, part 3

The decryption function If you are just joining this story you may want to start at part 1. In part 2, we discovered that a embedded controller update is performed by uploading a small ‘flasher’ program to the EC. This … Continue reading

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Unlocking my Lenovo laptop, part 2

The embedded controller In part 1, we looked at the communication between a Lenovo Thinkpad X230T laptop and battery, and discovered that there a challenge-response protocol used to authenticate ‘genuine’ Lenovo batteries. On the laptop side, this – and battery … Continue reading

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