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Messages - AdShea

Tools of the trade / Re: Solder pot
Anyone know what the pump is like for the wave/fountain machines? Given how cheap those pots are it might be interesting to make a fountain out of one.
Project logs / Re: PAW7 - Mainslog_Sensor
@Sleepwalker it seems you don't do much with power. On a usual drive design I've got 9 or 10 different grounds with up to 900V between them and only one will have anything more than a passing relation with earth ground (other than the earth connection that is).

For those keeping count that would be power ground (which is the bottom of the rectifier so about Earth-450V) six phase grounds (for gate drivers and desaturation detection, three for rectifier, three for inverter), digital ground (which floats but has high-impedance to one of the DC-Link rails), analog ground (same potential as digital), communications ground (usually close to earth, but I prefer to not tie it hard), and of course earth.
Project development, ideas, and suggestions / Re: Madelon LPC development board
With regards to the voltage monitor requirement, in the past I've had good luck using a schmitt-triggered buffer and an RC-delay circuit to do power up-reset delays.  Nice thing is that single or dual package buffers come in SOT-23-6, SC-70, and SOIC-8 from just about every manufacturer.
Project logs / Re: Xray machine tear down (56k no no) 4-29-12
Looks like the voltage multiplier and the like are inside the tube.  Personally I'd say see if you can fix the thermal sensor and try to make it run.

Then use a logic sniffer and figure out how to run the thing, give it a new controller, and use it for PCB inspection.
Project logs / Bus Pirate v4.0 FreePCB build. (or how MPLABX fails)
Well, my BusPirate v3 from sparkfun finally died (and the connector was backwards anyway).  By died I mean that the clock line fails self test and never switches high.

Whatever happened, I took this as a sign that I should build up the BPv4 board that I got from a twitter drawing a few months back.

So I ordered the extra parts I needed from Mouser, combined it with the eBay reels that I already had, and built up the board.


I used the cheap Abracon crystal that has a 4-land package.  It just barely fits the "Seeed SMD crystal" footprint.  (see the linked image).

Overall, I'd have to give major kudos to whoever did the layout (Ian?) for great spacing and large pads that make hand soldering a breeze.

I then tried to get code loaded on.  I'm running a pure linux box, and have MPLABX v1.00a installed.  I grabbed the SVN, opened up the Bus Pirate bootloader for BPv4, changed the project to use my PicKit3, fixed the error of trying to include <p24fxxxx.h> instead of <p24Fxxxx.h> (silly case insensitive windows guys).  But then I get

Code: [Select]
 /opt/microchip/mplabc30/v3.30c/bin/bin/pic30-elf-bin2hex: dist/default/production/firmware-v1.production.elf is not a valid object file.
make[2]: *** [dist/default/production/firmware-v1.production.hex] Error 255

After searching around, it seems that this is a known problem with no real workaround.

So, my question for all of you: is there any way for me to get a bootloader on here without having to find a Windows box with MPLAB v8?
Project logs / Re: Simple AM Radio Signal Generation
It should be a few kHz wide as you're mixing it with a few kHz bandwidth signal.  In the limit as you're sampling at 34kHz you could have a 17kHz wide AM signal transmitted.  Broadcast AM usually is only a few kHz wide and is band-limited to just over telephone quality.
Project development, ideas, and suggestions / Re: Underwater touch button/panel
Just remember that for capacitive methods, humans aren't much different in dielectric constant than water, so you'll want to use a pressure-based switch.  I'd just space two thin sheets (20mil) of Al with some foam and plastic.  Ground the pool side, hook the wall side to another cap of about the same magnitude as the resting sheet.  Tie the other end of that cap to your +5 supply (or +12 or whatever).  Put the midpoint into the input of a comparator and a resistor divider that makes the time constant on the order of a few 10ms.  Compare against mid-rails.  When the swimmer hits the panel, the squish will increase capacitance which will cause the voltage jump.  Your comparator will detect this, send a pulse, which you can use for whatever timing you want.