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Random stuff on a page.

I play in some bands.

Boys Boys Boys! which is an electro-pop & Indie Rock kinda band.  we try to be fun, and make sure both us and the audience are having a good time.. go and have a listen.. :)

I also play in a band called RATS.  we're not much like boys :)

Small Pocket device with a qwerty keyboard

posted 1 May 2013, 08:38 by alwyn zigzag   [ updated 27 Jun 2013, 20:11 ]

Any of the following would be awesome to get, gut and refit with a more powerful mainboard. possibly with a new LCD as well, if something of the right size can be found.

the Poqet PC
Psion 5 and Psion 5mx 
Atari Portfolio.  but the keyboard looks shit.
Gateway Handbook.
HP Omnibook 300 (maybe the others in the omnibook series as well?)
Compaq Aero
RIM Pager 950
RIM Pager 850

Using IR for simple serial comms

posted 20 Aug 2012, 18:41 by alwyn zigzag

Here is a simple scheme for using IR for a serial link for an MCU if you have a spare PWM/clock output.

Most IR receivers cost less than a dollar.  they have inside them analog signal processing smarts, and also bandpass filtering to remove background noise such as 50/60Hz AC lighting noise and sunlight etc. making the link more robust.  the bandpass filter frequency is typically something like 38kHz, etc.

IR transmitters are the harder part, since you need to modulate the IR signal to match your receivers bandpass filter.  The attached drawing shows how you can use a PWM output of a MCU and the UART to drive an IR LED with the appropriate modulation.

Maximum Speed.
The maximum speed that you can send over the link depends on the PLL locking speed.  The datasheet will normally have some details on how many carrier clock cycles are needed for a lock and to detect the data.  From most datasheets I've seen, 4800bps seems to be about the reasonable limit of good receiver/decoders

Maximum Range.
Not sure.  I'm going to get some parts, and then i'll test it :)


posted 19 Aug 2012, 08:57 by alwyn zigzag

interesting comments about long distance IR transmission.

IrDA Spec.

5mm LEDs

posted 10 Aug 2012, 08:41 by alwyn zigzag

Technical Details



ColourWavelengthLum. int. (mcd)IFVFVFVRView

(nm)@ IF (30mA)max. (mA)typ. (V)max. (V)max. (V)angle
White0.30/0.31 *30000503.64.2515°
Warm white0.5/0.43 *28000503.44515°
* Chromaticity coordinates

Switch Mode Power Supplies.

posted 29 Jul 2012, 18:22 by alwyn zigzag

I saw an interesting link on the page, to an old Linear Tech app note on switch mode power supplies.  
I do a lot of power supply design stuff for work,  these days, most switch mode power supplies are done with a dedicated switch mode controller IC. 

and so it was interesting to read through the app note and look at various discrete implementations of different circuits.

E-MU patents on the morpheus

posted 10 Jul 2012, 00:19 by alwyn zigzag

This product is covered under one or more of the following U. S. patents: 3,969,682;
3,986,423;  4,404,529;  4,506,579;  4,699,038;  4,987,600;  5,013,105;  5,072,645;
5,111,727 and foreign patents and/or pending patents. Morpheus is a registered trademark of E-mu Systems, Inc.


posted 20 Jun 2012, 05:33 by alwyn zigzag

tips for configuring metric gerber files for OSH park.

1)  files must be renamed to *.ger
2)  Use an NC drill file. 
3)  if the output is in .txt mode, then you need to rename it drills.txt
4)  drill file format should be 4:4, keep leading and trailing zeros, reference to relative origion.  

USB tool pack

posted 12 Jun 2012, 20:53 by alwyn zigzag   [ updated 12 Jun 2012, 20:55 ]

So, i bought a USB battery pack recently that let me carry around some extra juice for my mobile.  It was pretty sweet.

However, i think i can do something better.  The main issue with the gorrilla pack that i have is that it requires charging from a plug pack.

bascially if it could be a really useful usb-toolkit.

what i would like is:
1- Plugpack charging.  Ideally, be able to use any random plugpack you find lying around.  so, 5V-24V in with auto polarity detection..   Not sure how to handle what current you can draw detection.. 

2- USB charging.  needs to be able to detect if it can pull 500mA or 1A from the usb port.

3- USB hub 2 or 3 ports would be good.  each port will provide 1A to charge high current devices.

4- a way of using the USB hub so that it will change over one of the ports to be a upstream facing port if you have an OTG phone plugged in.  a switch/pushbutton perhaps?

5- really low current idle/sleep state.  it should still hold 80% charge at 2 months after a complete charge. 

6- card reader?  is this useful?

7- E-ink display?  is that needed?

8- Serial port?  would this be useful?

9- Small enough to be put in a coat pocket.  it doesn't need to fit in your jeans, but that would be nice.

10- provide enough juice to recharge an iPad, 2 or 3 times.

General posting

posted 11 Jun 2012, 19:52 by alwyn zigzag

this post doesn't really have too much in the way of content.  

Just some things that would be interesting to benchmark.
Cortex M0 at 50Mhz vs Cortex M3 at 50Mhz running some benchmarking code.

the M3 supposedly has single clock cycle multiply, so it would be interesting to see the difference.

perhaps even monitor the power draw during the operation to see if there are any efficiency differences..

A list of rack mount guitar Pre-amplifiers

posted 14 Apr 2012, 04:42 by alwyn zigzag

Roland SIP-300.  Discreet solid state.
Hiwatt 2000 series Pre-1
Kitty Hawk Quattro
Kitty Hawk Testarossa
Lee Jackson Perfect connection....
Marshall 9000 series....
Soldano SP-77
Rocktron (Several)
Marshall JMP-1
Groove tubes Trio
Peavey Rockmaster
Hafler Triple Giant
Engl E530
Rexx 610s
Pearce G1
Rocktron Voodu Valve
Rocktron Piranha 
A.C.T. for Analog Control Technology
Hafler Triple Giant
Kasha Rockmod II
Mesa Studio Preamp
Peavey Rockmaster
Hughes and Kettner Attax
Digitech Twin Tube
Tech21 PSA-1
yamaha pg-1
Demeter TGP-3
Rolls MP45
Hughes and Kettner Access
Scholz Rockman
Soho QTR-1 
Peavey Tubefex
Bogner Fish
Egnater IE4
Egnater M4
GT Trio (Brownface)
Pearce G2P
Mesa Quad/Studio

Mesa Triaxis
SoundClinic Climax
HK Access
Frenzel FM-pre
S2Amps Pre2
Digitech GSP-5
Metaltronix M1000
Peavey ProFex
Kitty Hawk Quatro
Digitech GSP-2101
Randall RM4
Boss GL-100
Ricktron ProGAP
Rockman XPR
Gallien-Krueger 2000CPL
Yamaha DG-1000
Digitech GSP-2101
Rocktron Chameleon
Hafler T2 and T3
JHD Audio UTP-1
Hughes & Kettner "Master" series
Lexicon Signature 284
H&K Tubeman plus 

Matchless GPR
SGX 2000
Yamaha DG1000
The Fish
CAE 3 +
Soldano XR 88r,
Soldano X99
Langner DCP-1
VHT Valvulator
Mako Mak4
CAE 3+
Langner DCP-1
Mike Morin preamps
Demeter TGP-3
Egnater (Natec) preamp.
Alembic F-2B
Rocktron Gainiac

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