Is the wikipedia main page always this weird, or is it an April 1 thing?
I built a Shruthi XT!
The circuit boards and panel were group bought with the Pusherman facebook group, I ordered the components from Mouser, and built the case myself out of walnut left over from a dulcimer build.
I used the BOM from the Shruthi XT build page, with Mouser’s BOM import tool. Generally everything worked fine with a couple of caveats: it auto-detected the wrong encoder (the horizontal mounting version of the same model) so I had to order another one. The MIDI sockets it found were also different, and had a metal spring on the outside which I had to remove in order to get them to fit the case.
Watch out when soldering the board-to-board connectors! I put them on the wrong way round the first time and had to remove them, which was tedious.
On my future MI builds I’m going to try using Bourns PTV09 potentiometers instead of the Alps ones on the BOM, as they cost significantly less and should be approximately the same quality.
I built the SMR4 MkII filter board but am going to upgrade to the 4 Pole Mission as soon as I get the board and components for it (along with boards for an Ambika, and a normal size Shruthi to inherit the SMR4…)
Overall I’m very impressed with the synth! It sounds great and is a lot of fun to make sounds with, although it’ll take me a little while longer to get to grips with all the features and wavetables.
If you want to get into DIY synths, but skip past the “circuit which makes bleeping sounds” straight to “professionally usable synthesizer” I’d definitely recommend building a Shruthi.
Future improvements planned: upgrade to a 4 Pole Mission filter board, make a laser-etched walnut front panel, more UI improvements in the software, maybe a built in battery and USB port for powering MIDI controllers.
Seeing a lot of people talking about Germany in response to #Cville. Unfortunately, DE has it’s own problems with rising “alt” far-right. Saw this in town today:
It’s an election poster for the AfD (“Alternative for Germany”). Roughly translated it says “Burkas? We like Bikinis. Trust yourself, Germany!”. They’re growing in popularity, especially in places like this town, historically with strong (10%) NPD (Nazi) voting base. Their posters are either bullshit like this, or cleverly framed statements about borders, pensions, schools, children, “taking back control” etc.
The old Fitbit and Fuelband which Aaron Parecki gave me a few years ago (thanks Aaron!) don’t hold a charge anymore. The Fitbit battery is near impossible to replace, and with the Fuelband I decided that as there’s no way of loading custom firmware (which would let me get at data without an internet connection and proprietary apps), it wasn’t worth trying to get replacement batteries. So before throwing the devices away, I took them apart.
I didn’t find out much which I hadn’t already seen in teardowns, but these devices have such strange form factors that it was fascinating to see the engineering up close.
The rubber coating comes off very cleanly. Here you can see some of the funny curved traces used on flexible circuit boards:
The LED array, with “Just Do It” written on the top of the PCB (invisible to the end user). On the sections of flex between the more solid boards you can see the unbelievably fine traces:
On the back of the LED matrix section, with a part number. To the right you can see the jaggedy bluetooth antenna trace:
The fitbit isn’t so interesting. Removing the cap with a heatgun reveals a tiny circuit board with a tiny battery and vibrating element.
I also opened up the dock, as I noticed that the USB cable was power only, with no possibility of wired data transfer. The third pogo pin must be for the reset switch, which is mounted in the dock. There’s a little IC in there too, but I was more interested in seeing how the pogo pins were attached to the board. Turns out they’re just soldered straight on:
I’d love to have been able to flash custom firmware to the Fuelband, it’s a lovely bit of hardware, and manufacturing something like that is completely out of the question for a hobbyist. There are so many fun things which could be done with a device equipped with an LED matrix, accelerometers and bluetooth — a wearable MIDI controller, for example.
That possibility would also have made replacing the batteries worth doing, and in doing so saved the device from the landfill. Free software and open hardware isn’t just political, it’s better for the environment.
Doing some prototyping+testing for the next MIDI-enabled gurdy board:
My current approach is an Arduino (Genuino) Uno with a custom made board with a line of hall effect sensors, and the various other boards plugged into the Arduino. It works, but there are various problems — wiring the whole thing together is a hassle; the limited I/O on the Uno requires me to multiplex the sensors, introducing delays; hand-soldering through-hole sensors means they’re all in slightly different positions; and a single line of sensors isn’t enough to cover the whole throw of a key, resulting in notes turning off when they’re bent too far.
I heard about emsproto.com and was initially considering designing a board containing the sensors and microcontroller myself, and having it built, but after drafting up a very simple one-component test board and seeing that there’s a base cost of €200 per board for PCB and assembly, I decided on another approach.
The next version of the board will be a custom designed sensor and breakout board with two rows of surface-mounted hall effect sensors, into which I can plug a Teensy 3.5, removing the need for multiplexing, vastly increasing the speed at which the system can run, and opening up various possibilities like easy-to-implement USB-MIDI support.
FOR SALESOLD: Two newly built Hurdy Gurdies
The first two instruments from this winter’s series are now for sale. The new design is an evolution of my previous instruments, aiming to be more compact whilst having a loud, mellow, balanced sound. The instruments fit nicely in Ritter Alto/Tenor sax bags (I’ve flown several times with this model as hand luggage without any problems).
Vio #4 for €2700 + P&P from Germany
This instrument can be seen played together with a violin in this video from Folk Marathon 2016.
2x melody strings (G and g)
2x drones (C and G)
2x trompettes (C and G)
Fully chromatic two octave keyboard (including F# in the upper octave)
Height-adjustable melody string bridge
Adjustable drone bridges
Fitting capos and/or an amplification system is also possible.
Vio #5 for €3150 + P&P from Germany
2x melody strings (G and g)
2x drones (C and G)
2x trompettes (C and G)
4x sympathetic strings (C, G, D, A)
4x capos (one for each drone and trompette string)
Three channel active amplification system
Fully chromatic two octave keyboard (including F# in the upper octave)
Height-adjustable melody string bridge
Adjustable drone bridges
Some more photos:
Both instruments are now sold, but I may be available for new builds over the next year, Contact me at barnaby@waterpigs.co.uk if you’re interested.
Interested? Questions? Contact me at barnaby@waterpigs.co.uk for more information.
If you are blessed with high expectations of yourself and others, trust them, stick to them, act on them.
from today’s XKCD “Settling” xkcd.com/1768
