mesh-drum-pads

One of the reasons that I’ve not posted anything new recently is that I’ve been learning to play the guitar, and now that I’ve got to the point where I can play some almost recognisable songs, I wanted some accompaniment and bought a cheap electronic drum kit. I took the cheaper option and got a kit that had a mesh snare and rubber toms, but then instantly regretted not getting the full mesh kit as the rubber pads make a lot more noise.

I thought I could just buy mesh replacements but the cheap ones aren’t sold separately and the easily available Roland ones are very expensive. Luckily it turns out that it’s really easy to make them at home. The actual sensor is just a simple piezo element, there’s no active electronics in the pads at all.
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magicball
Recently a question came to me from a friend of a friend… they had a globe that displays text messages that they wanted to use as a Christmas decoration, the only problem was that they couldn’t change the message because it was password protected… could I unlock it?

Hmm… maybe… bring it round and I’ll take a look…
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hdmi-splitter-hack-attiny9-installed-zoom

One problem with my HDMI Ambilight project is that it can’t handle encrypted content, or more accurately, it can only handle encrypted content if I spend a lot of money and get an HDCP license, which would then allow me to buy the version of the ADV7611 chip that has built-in HDCP keys. While this doesn’t cause me much of a problem as I tend to watch almost everything via MythTV, with the TV on the HDMI port and the HDMI Light on the DVI port, it would be nice to be able to use an HDMI splitter between my AV receiver and TV instead, and have it still work on the odd occasion when I watch a BluRay directly.

Luckily, my post announcing HDMI Light version 2 was featured on Hackaday, where a couple of people pointed out that it’s actually quite easy to disable the encryption in some HDMI splitters, effectively turning them into HDCP strippers. Even more helpfully, RoyTheReaper described exactly how to disable the encryption in an HDMI splitter I had lying around in my junk box.

While his method works perfectly as far as disabling the decryption is concerned, it has the side effect of also disabling all of the nice little extras that come with HDMI like automatic input switching and controlling the AV receiver volume from the TV remote. What I needed to do was find a way to let the microcontroller in the splitter continue to do all the other things it does while stopping it from enabling encryption.
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hdmilight-v2-3It’s been over a year since I created the first version of my Ambilight clone, but I finally found the time to return to it and add some new features. I was originally planning on adding colour correction (to correct for the purple wall behind my TV) and output delay (to get perfect synchronisation with the TV), but I got a bit carried away and have added a whole raft of new stuff.
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bluray-drive-bricked-dark

I buy a lot of DVDs and Blu Ray discs, but I very rarely watch them straight from the disc. As soon as I get a new one, it gets ripped to my MythTV backend, from where I can watch it at any time and on any screen in the house. Until recently, I’ve been happily doing this using MakeMKV and a Plextor USB Blu Ray drive, but unfortunately it seems that the film industry thinks the best way to reward me for buying so many is to brick my drive.

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bathroom-touch-switch-installed-2

Having previously created a Border Router and a Six Channel LED Dimmer for my custom Myha home automation system, the next item on the list was to create a Myha version of the touch switch that I’d previously made for the Rako system. This was actually the third version of the touch switch as I’d made two Rako versions, the first using an official Rako switch contact module and the second communicating directly over the air after I’d reverse engineered the RAKO protocol.

As this was version three, the bulk of the hardware design was already fairly well proven and little had to change, mostly it was just a case of changing the radio and firmware. However, this was the first version to be installed in a wall, and this is where a few surprises were to be found.

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ha-6ch-dimmer-assembled-front

At the beginning of the year, when I sent off the Raspberry Pi 802.15.4 Radio design to Smart Prototyping to have the PCBs manufactured, I also sent off the design for the second Myha home automation device, a six channel LED dimmer that’s intended to control my bathroom light. Unfortunately this design wasn’t quite as successful as the radio interface. It works well enough that I can still use it, but more through luck than anything else.

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ha-raspi-radio-installed-1

Shortly after creating the Contiki/Zigbit home automation proof of concept over Christmas, I laid out a 802.15.4 radio interface PCB for the Raspberry Pi and sent it off to Smart Prototyping for manufacture. With this interface and the 6lbr router software I can turn a Raspberry Pi into a nice small, self contained Ethernet to 802.15.4 border router, which will form the heart of my new home automation system.

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As I’ve been making more custom automation devices, I’ve come to the realisation that I don’t actually have to be restricted by the limitations of the Rako protocol. I could start again from scratch with my own custom protocol and have no restrictions at all.

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This is my MQTT client library for Contiki.

It is completely asynchronous, starting a new process to handle communication with the message broker. It supports subscribing, publishing, authentication, will messages, keep alive pings and all three QoS levels. In short, it should be a fully functional client, though some areas haven’t been well tested yet.

See the example below for usage.

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