Friday, August 16, 2013

3D Go Game

Go is a fun game.

Playing with a friend we talked of variations that could exist like a 3 dimensional version. Below are our experiments.

Digital versions exist but we set about making real "boards". A problem exists relating to accessing the inner points. The players need a way to get to the center points. One solution is to make the board large enough that you can fit your arm and hand in between the vertices. Doing this there is a limit to the total number of vertices that can exist; if there are too many you can't access the inner vertices. Her work in progress efforts are below, the outer vertices are constructed with string in a wooden frame.

 An alternate solution to the problem of accessing the inner vertices is to make a "board" that comes apart into multiple pieces. The photo below are my efforts to make more of a tabletop sized board. It is unfinished but this would be the right hand side. The cube will have a split in the middle so you can move them apart. Distance between vertices was determined by finger size. It still may be a bit tricky to get to some of the inner most pieces.

It is made out of wire soldered together, with some loops for the feet.

The traditional 2D board is 19 by 19 grid. I do wonder about the significance of 19 being an odd number. My wire board is 10 by 10 by 10 and perhaps this even number will have an affect on game play. In future it would be possible to cut it up and make a 9 by 9 by 9 grid if an odd number has significance.

Another problem is what do you use for pieces? We had a few ideas: little loops of pipe cleaners or perhaps a cd / donut shaped discs with a slice in it to slide into place, or perhaps something magnetic. To be explored!

Tuesday, August 13, 2013

Altoids Tin Portable USB Charger Port

I built this simple project in an evening. It is a portable battery powered USB port in an altoids tin to power USB things. I built it to have a portable way to charge my mp3 player. The batteries are 18650 rechargeables (which are also cells used in some laptops and apparently the same form factor of batteries used in some electric cars) and it also used a cheapo ebay voltage regulator circuit. The hole for the USB port was marked with pencil (rather than scratch up the outside of the tin). I poked through the metal with a knife to start a hole and finished off the hole with a small square file. Initially I tried to glue the port in place with glue. I also soldered the port to the tin for some more strength.

Some other features like an LED to show if something is connected or an LED to show if the batteries are low on charge could be some nice features to possibly implement in the future.

Friday, July 26, 2013

Raspberry Pi Portable Case Build

(my Raspberry Pi)

I have been working on a case for a Raspberry Pi. The Raspberry Pi is a small single board computer that runs Linux. You can check out a few videos describing the board and the Raspberry Pi Foundation's goals. My plan was to make a pocket sized clam-shell palmtop computer similar in size and inspired by the HP-200 LX palmtop computer from 1994.

(picture from Wikipedia with iPhone for size comparison)

The plan is to have both a screen and keyboard. It is currently powered by 2 18650 batteries in series. Here it is running off the batteries with a screen. The screen is relatively cheap and was sold as a screen you would have in your car showing a camera for use as a backing up camera system. As such it is designed to be powered from a cars 12 volt battery. I have mine running straight from the 18650 batteries. See Cheap Miniture LCD Screen. Also on this page is a link to converting the screen to run from 5 volts. It seems as if the screen internally runs at 5 volts but has a regulator to drop down the 12 volts coming in from the car battery. A cheap circuit board with a switching regulator chip bought from ebay regulates voltage from the batteries down to 5 volts to power the Raspberry Pi. In the picture I have the power hooked straight into the GPIO see the pin-out here. However, I think in the future I will power the pi via a powered USB hub (which can be seen just above the Raspberry Pi board in the photo below) instead of directly into the GPIO.

The screen is not of great quality. A possible alternative is using a 4.3 inch LCD via HDMI that is used in the HTC Desire HD.

Another note on power consumption: At some point I may try and swap out one of the chips on the Rasp Pi board for better battery life. A 3.3 volt regulator can be desoldered and swapped out for something more energy efficient. Check out some info on that here and here.

I decided to make the case of 2mm think aluminium. Below is a knock up held together with tape to see if everything fits.

 To the left is the battery holders for the rechargeable 18650 batteries. On the Pi board I have at this point removed the USB port to make more room as this port will be connected directly to the USB hub. On the back panel from left to right is a hole external power input, audio jack and 4 USB ports. Below is the back panel showing the USB ports.

It is held together with a 2 part epoxy called JB-Weld. 


The keyboard I intend to use is an XBox 360 chatpad. Info on getting it communicating with the Pi can be found here

Slowly I am learning how to work the aluminium into the shapes I want and it has required quite a few tools. Information and a few tips I wish I knew when I started I will post in an upcoming blog post.

Unfortunately it is larger than I had anticipated and you would need to have a rather large pocket to fit it into. I like the palmtop form-factor and it seems to be something that is not at all popular in part I think due to smart-phones.

Still to make is the top half of the case holding the LCD screen and the panel that will hold the keyboard. Also all the wiring is yet to be done. I have begun to research a way to finish off the exterior of the case, perhaps with either polishing or painting.

Another some what similar project by Ben-Heck.

And, a picture of my electronics work bench:

Sunday, May 12, 2013

Modular Analogue Synth Doepfer DIY Little Dieter Build

In researching modular synths and looking for a way into building my own I found the Doepfer DIY circuit board. The board provides a number of basic building block modules for a reasonable price. It is a DIY board however and it's intended the end user will come up with a panel or/ and case.

After putting together my Shruthi-1 I found this thread on the Mutable Instruments forum on a kit called the Little Dieter that was put together by a guy called Frank. You can check out his webpage here and his Flickr page here which also has instructions for putting the Little Dieter together. It provides a panel in eurorack standard and all switches, pots, LEDs, mechanical bits, resistors, knobs for the pots and connecting socketed wirey bits.

A Doepfer DIY board and the Little Dieter seems like a good way to go so I went ahead and bought a kit.

And here it is!

The blank panel. Beginning to put in pots....
Rear side of the almost fully stuffed board of pots and jacks.

 Front panel with pots and jacks installed ... Also visible the Doepfer DIY board.
 The slow and tedious task of soldering hundreds of point-to-point connections. Here are the beginnings of the ground wiring. I used a combination of wire going from point to point. Also in some other places I experimented with using some wire without a coating to make the connections.
 Continuing with ground wiring. I put some heat-shrink wrap on some of the leads of the LEDs.
 Further wiring...

And completed with knobs attached.

No power supply yet so I am yet to test it.

Thursday, May 9, 2013

Analogue Synth Panel DIY

I have been playing with and learning to work with sheet aluminium recently to make some panels for my modular synth project. I used 2mm aluminium because this is what is used in the Doepfer panels. I got out the ol' paper CAD to sketch out some ideas. The plan is to make a converter to go from 1/8th to 1/4 inch jacks and visa-verse. I mocked up a prototype on cardboard to see if the sockets would fit together on the back. I took height and width dimensions from the Doepfer a100 construction details page to make the panel conform to the eurorack standard.


And then I set about hacking into my sheet to make the panel. Here it is:

 ... and where it could fit in my rack:

The cut was not perfect. There is an art to cutting a straight line with a hack-saw I found. I cut to one side of a scored line to continually reference where the cut should be. Of course it would be easier with a workshop full of pro tools but we shall see how this goes!

I had a brief play also with hand drilling some holes for the sockets but there were off by several millimeters. I'll continue to try and get a better result, failing that I may have to get access to a drill press.

I have been thinking also about how to apply labels to the metal surface and have a few ideas I will play with.

Shruthi-1 Synthesiser Build

I put together a Shruthi-1 kit in a few evenings. It's a nice little synth with a digital oscillator and an analogue filter. Web page for the Shruthi-1 is here.

(nearing completion)

The kit does not come with an AC adapter. Not all adapters are created equal I found out! The circuit requires a voltage within a specific range. No problems here but it turns out the markings on an adapter can specify not what is being output but that the adapter will output at least this amount. Measuring the output of an adapter labeled as 9V gave me 14 volts for example. Something to be aware of! Link to some further info on AC adapters here.

and here she is in her natural habitat...

Wednesday, May 1, 2013

DIY Patch Bay

Some time ago I made my own 1/4 inch jack patch-bay. The wood was in its previous life floor-boards. The metal was an L shaped piece of roof gutter that was hammered flat. I did not know at the time about normalling any of the connections, so cords need to be connected in the front for any connections to be made. At least this way it is easy to visually see what is connected to what. Most of the materials were scavenged and the only thing I bought were cheap 1/4 inch jacks that half fall apart (you can see were one of the small rings has just fallen off) and some wood screws. The thing is quite heavy. Total build cost was less than $10. Dymo tape for labels. Some of the holes are spaced a bit wonkey but it adds to the character I guess. :-P

Tuesday, April 30, 2013

Modular Analogue Synth Build 2. Patch Cords

I made some patch leads. I sourced some plugs from ebay, I just used stereo ones because they were cheap and I could not find any mono ones. The plugs are stereo but they are wired in mono with a shielded single core wire/cable. A slightly larger diameter might have been nicer but I think they'll do the job. I made short and long ones.

It is surprisingly labor intensive, these were made in an evening.

Much cheaper than bought ones!

Monday, April 29, 2013

Modular Analogue Synth Build 1. The Case.

I am in the process of building a modular analogue synthesiser. First up, the case! A number of off the shelf cases exist for building a modular synth, but none are cheap. Some time ago I stumbled on the fact that a piece of furniture from Ikea (Rast bedside table) conforms to the 19 inch rack standard for audio and industrial gear. I do wonder if this is coincidence or weather the thing was designed with this multi-purpose in mind. In any case (ho ho) it provides 19 inches by 6U. Two rows of euro-rack will fit nicely! I decided to go with the euro-rack format as apposed to the larger Moog / for a few reasons. One of the large reasons is the size of both the modules, jacks and cables.

I've bought some Tip-top audio mounting ears and rails to go inside the Rast. They strike me as being quite expensive for what they are but nonetheless this DIY route is cheaper than buying a pre-built case.

I found a piece of wood on the street and cut it up for use as the side mounting points. The inner wood rails and nailed in place and wood screws hold the tip-top audio rack ears in place.

Still to come, power supply, DIY modules, patch-cables, drum machine clone modules.