…and I guess I use that term lightly.

I’ve been building a MIDI modulator for the DRSSTC tesla coil I put together last year.

One of the problems is tuning a 555 based oscillater to match MIDI note numbers. I played around with Excel for a while, but couldn’t really get anything useful going. So I wrote something in C# to help.

555 to MIDI calculator

This application calculates the frequency of a standard 555 timer in Astable mode based on the values of C, R1 and R2. I split R2 into a fixed resistance (R2a) and a variable resistance (R2b). R2b is controlled via the MCP42100 digital potentiometer that can be hooked up to an Atmel microprocessor very easily.

After calculating a set of frequencies for the 555 timer, it then goes on to calculate the set of frequencies for standard MIDI note numbers.

Finally it compares the legal MIDI note numbers to the table of 555 values, and comes up with the best match for each note in table 3.

I’ve not yet implemented the results in hardware to see how musical it sounds, but on paper it all seems to work well.

The application is a C# solution available here (also contains compiled runnable version).

Update; it does work!

Even thought the sound quality is very flaky – this first run shows the tuning is just about right.

I’ve been going through all my shelves in the basement and trying to complete as many of the unfinished projects as I can, just to clear some space.

One of the things I needed to do was box up the old Staco Autotransformer I have. I was faced with this:

Hmmmm...

But luckily I found Tim Reese’s webpage that explains how to hook the variac up for both 120/140v output.

http://www.nmr.mgh.harvard.edu/~reese/VariacPage/

So that’s one more project finished.

Green for 120v and red for 140v

Yay!

Several years ago I asked my workmates the question:

“If a government needs more money, why can’t it just print more?”

We talked about inflation, and the linking money to tangible assets like gold, but soon realised that we didn’t have enought information to come up with a good answer.

I recently saw the “Money As Debt” video on youtube – if you’ve not seen it then I urge you to take about an hour of your time to view the whole thing.

Here’s part one (of 5):

I have no way of really verifying the information presented in the video, but it makes for compelling viewing. I can also see how an economic system like this could have evolved.

So far I’ve talked to 3 tellers and two bank managers – I asked them “When I get approved for a loan, whose account is debited when the credit is made to my account?”

No one knew where it came from – just from “The Bank”. When I told them about the idea of the 9:1 lending ratio, nearly all of them said “I can believe that”.

The longer I live, the more I come to believe that “Do what you want, just don’t get caught, shall be the whole of the law.”

Taking a break from robots and lasers to work on my MIDI to DRSSTC Tesla coil adapter. (?)

How cool is the 555 timer? I just discovered that by modulating the control pin (5) with a varying voltage you can alter the output frequency.

Effectively a VCO – wow.
(Do I sound like a geek yet?)

Although my attempts to use this with the Atmel168 have not been too successful as it only provides PWM analog out, and even with smoothing via an RC net it’s still too shaky to produce musical notes.

So I’ve got two choices, either use a DAC to send out the control voltage, although the range is a bit limited. Or use a digipot to either act as a potentiometer and supply control voltage, or replace R2 in the astable configuration of the 555.

I think I’ll try the latter…

Not sure, Mum thinks I do a bit…

Maybe a bit...

She’s got better hair then me…

I just received the K9 flatpack kit.

Blue tape is optional

Some of you know that a couple of years ago I started building a K9 (I thought it better to start with something small and angular before tackling a big curvy monster like the Dalek). I started strong, but things soon got out of hand, and my (then) poor soldering skills really were a major obstacle.

Things have changed quite a bit and there are some excellent robotic kit parts available – including this wonderful flat pack K9 made of sheet styrene. Light as a feather, and should solve a bunch of the issues I had with the original.

And the rest of him...

Everything really does fit on one board...

I just got the first prototype PCB back from BatchPCB – there were a couple of errors (on my part) but the board is really well made and seems to work OK.

I need to correct the silk screen layer and update the wiring for a couple of things. I might add some test points just to make diagnosis easier…

In the box - looks much tidier

Now with dual core Arduino's...

Some of you have been following my rebuild diary on the laser harp…

Well that’s got the hardware pretty much complete – now the difficult task of rewriting the firmware to support all the new features.

But first, it’s time for a cup of tea…

I’ve just been watching the Six Million Dollar Man episode “The Return of Deathprobe” (all one word, not Death Probe mind you).

It's back, and this time it's black...

As I kid I was completely in awe of this thing – and it’s only watching as an adult that I realise how completely silly the plot really is.

I did notice one thing, it must have been incredibly dangerous to work with the prop. It really looks like it’s made out of metal and flails around rather uncontrollably in certain sequences.

Watch out Steve...

Lee Majors narrowly avoids being side swiped during the sequence where he’s trying to blind the thing by spraying foam over the “visual sensors”.

Oooh that was a close one...

Scary…

I’ve been working away on a new version of the laser harp for 2009. The old one broke down after heavy gigging so I thought it was time to rebuild it, (we have the technology), to be better, stronger, faster than before…

Laser Harp 2.0 coming soon...

Built out of an old black box flight recorder – so quite a bit stronger than before…