My client needed to receive a relatively large amount of data on a mobile device, from an embedded system, and process it in near-realtime.   The simplest method for communication with a whole host of mobile devices is to go over bluetooth low energy, but this protocol’s main concern is more about power conservation than throughput. …

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After this tutorial, you’ll know “in your bones” how to deal with the weirder stuff, when it comes to time-dependent values. It’s easy to find formulas to plug into to for simple cases, like a steady DC voltage or nice sine waves with known peak values but what happens when things aren’t so straightforward?  Say…

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I’ve recently had to determining the frequency of some arbitrary repeating signal, from a stream of sampled values. In a simple universe, you could just wait for a specific value to come in–say the peak value–or monitor for the zero crossing or somesuch. However, the particulars in this case included the fact that, in addition…

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Received a Hantek DSO-2090 USB oscilloscope today and put it through a few paces.  Here are the results and my impressions from using the device a bit, as well as a few tips for working with it under Linux. The first thing to note is that, in terms of DSOs, this thing is dirt cheap…

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As promised, the NanoKeys library has been made public and is now available on it’s own project page! One noteworthy change is a modification to the key send/key clear algorithm that allows for much quicker transmission of key strokes and a snappier user experience.  Here’s a short clip of the new functionality in action: And…

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I’m finishing up the docs for NanoKeys, a small BLE Nano (and probably any mbed BLE API supported devices) library that gives you an easy way to create a bluetooth low energy keyboard that you can pair with using any mobile device. The project page, code and documentation will be up shortly (in the projects…

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Just got my hands on RedBear Lab‘s Duo—what promises to be a great little BLE/WiFi combo—and got some preliminary testing done.  By the end of the seven straightforward steps detailed here, you’ll know all the basics about the Duo and have your own “Arduino” code running on the device, too.  Other than my own ramblings,…

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So it’s the middle of the night and I find myself in a jam… hm, a lot of my stories seem to start that way.  Anyhow, it’s the middle of the night and I’m badly stuck: I need to talk with a two-wire chip I have on a breakout, but the I²C communication lines need…

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I do not enjoy dealing with the vagaries of calendar dates and times… Actually, I pretty much hate it. It’s mostly because I have little patience for arbitrary rules and convoluted systems, and anything as old as the notion of date-times is always filled with historical cruft: half-baked rules, a bunch of incompatible, random-looking, bases…

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I love Adult Swim’s Rick and Morty so, for Halloween this year, I created my own version of Rick Sanchez’ Portal Gun–including a 3d-printed enclosure, printed circuit board, negative energy density tube/crystal thingy, wave file player and laser. Here, I’ll go over the design and construction, as well as a few lessons learned along the…

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