Widget of the Week #4: 8 x 7-segment display MAX7219

A quick one this week after last week’s marathon. Projects often need a few digits of numeric display – from thermometers to clocks these eight digit displays are a cheap and easy-to-use solution.  Commonly known as MAX7219 but that doesn’t refer to the display at all but the multiplexer chip that drives the LEDs from a serial input.  It’s also found in 8×8 matrix displays that we’ll come back to in another WotW. At a current price of around a pound you can pair one with a NodeMCU to make an NTP synchronised clock accurate to fractions of a second for…

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Widget of the Week #3: RGB LED arrays

Everyone likes addressable RGB LED arrays, they can be built into almost anything and they’re fun to program cycles and chases for. First let’s cover some terminology.  We’re talking here about the LEDs arrays in which each pixel can be individually controlled.  They come in different formats – flexible strips, panels, bars, rings and individual pixels, but these all use the same device. We also need to distinguish these LEDs from ordinary RGB LEDs which have no-board electronics but present three pairs of pins or a pin per LED and a common anode or cathode.  There’s also potential confusion with strips that are simply RGB LEDs…

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Widget of the Week #2: NodeMCU

I bet everyone who knows me was wondering how long it would take before I posted this one? The basic ESP8266 modules such as the ESP-01, -07 and -12 are small and cheap but not hacker-friendly so there are various modules around that put an ESP module onto a breakout board and provide essential functions such as voltage regulation, USB-serial and level conversion.  The forerunner is the NodeMCU which was originally intended as a Lua/NodeMCU firmware development platform but is perfectly good for other environments. The heart of it as you can see in the picture, is an ESP-12E module that…

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Widget of the Week #1: ESP-01 module

For the first of an irregular series of ‘Widget of the Week’ in which members will share the fruits of their frighteningly serious AliExpress and Banggood habits, I bring you the module that started it all, the ESP-01.  Intended for use in wireless serial applications, hackers soon found that it was field programmable and immensely versatile, not to say powerful – having not just far more memory and a faster CPU than the mainstream Arduinos but integrated WiFi with a pretty comprehensive IPv4 stack. On the one hand it’s somewhat hamstrung by having just three i/o pins but on the other, it…

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