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1  Community / Exhibition / Gallery / Re: SMBus Laptop Battery "Hacker" with phi_prompt LCD user interface on: November 09, 2011, 09:50:31 pm

What's the status on this project?
2  Using Arduino / Project Guidance / Re: Very Sensitive microphone/sensor for 'stethoscope' ? on: September 17, 2011, 08:29:44 pm

Still have some schematics around?

Sorry. This was in the pre-digital world ;-)

The analog sound could be sampled by the Arduino somewhere ...

The problem isn't getting enough gain. It's in differentiating between the signal you want and the noise from the environment. I actually had to add some weight to the speaker, simply by gluing on some washers. Then, this speaker/mic was attached to human skin, not a hollow tree.

3  Using Arduino / Project Guidance / Re: Very Sensitive microphone/sensor for 'stethoscope' ? on: September 14, 2011, 11:30:22 am
I've built an analog stethoscope years ago. What worked very well was a small speaker attached to the skin. You just have to be careful not moving it.
4  Forum 2005-2010 (read only) / Troubleshooting / Re: ROV motor on: September 08, 2007, 03:40:27 pm
Good source for motors: rechargeable power drills. Small ones can be had for 5-10 euro. They even come with NiCd cells and a charger. I bought some and they have a 3:1 gearbax, wich seems ideal for most boat propellors. They're not waterproof, evidently.

I am building a land prototype first, wich will be wireless. Underwater, you can forget about wireless comms, I think. Hance, GPS will probably not function, unless you are really close to the surface.

Sure, underwater modems exist, but they only offer a few hundred bits/sec...

I really hope someone here will prove me wrong about underwater comms, tho  :-)
5  Forum 2005-2010 (read only) / Troubleshooting / Re: Can someone verify my schematic? on: September 03, 2007, 01:03:56 pm
You put C3 and C4 in series with the supply voltage. They should be connected between VCC and ground, otherwise there will be no supply voltage to the chip.

6  Forum 2005-2010 (read only) / Bugs & Suggestions / Re: USB Suggestion on: January 04, 2008, 06:50:45 am
Mini USB is in fact a standard and every device I have, can use the same cable and power is provided over this cable just like a full size USB.  Maybe you are getting confused by the new micro USB that is starting to show up?

Nope, the ones I have all pretend to be mini USB. One's from a recent Chinese MP3 player, one from an Epson camera from a number of years ago, one from a recent no-brand GPS and the last one from a no-brand portable harddisk. None of those carry power and they are not interchangeable. They simply don't fit. It's a hassle cause they look exactly the same.

So, mini USB might be a standard, it seems not to many manufacturers are following the standard...

And I'm sure replacement cables will be *very hard* to find if I ever lose one of these. The same story seems to apply to mini firewire (IEEE1394) cables, BTW.

7  Forum 2005-2010 (read only) / Bugs & Suggestions / Re: USB Suggestion on: January 02, 2008, 08:35:20 am
Unfortunately, mini USB connectors are not standard. I must have at least four different types lying around and it's a real PITA to find the right one each time. And most/all of these don't carry power, only the serial comms, so you 'd have to power the Arduino from batteries or another power source, not from USB power.

So, to me at least, it seems like a bad idea. If you really want a smaller connector, why not use the FTDI serial to USB cable?

8  Forum 2005-2010 (read only) / Interfacing / Re: resistive touchscreen and arduino on: October 02, 2007, 09:33:39 am
It would help if you could tell us something more about the touchscreen. Make, model number and so on...  :smiley

The four wire connection might use PS/2 mouse emulation or it might be serial, but that's hard to tell. I doubt if it is simply analog, bit even that's possible too.

9  Forum 2005-2010 (read only) / Interfacing / Re: Using a Speed Controller of a Model Aircraft on: August 09, 2007, 09:31:17 am
You can use code to drive servo controllers. The kind of motorcontrollers you show in that link, is fully compatible with it.

BTW These kind of motorcontrollers are PWM. They don 't really provide 0-14 VDC.

If the car needs to reverse, you 'll need another type of controller, called a "fyll H-bridge". Airplanes don't reverse...

And these kind of RC motor controllers can be bought very cheap on eBay. Have a look here, for instance:

10  Forum 2005-2010 (read only) / Workshops / Re: Workshop Video Tutorials on: July 23, 2007, 11:35:22 am
Tom's videos were here: but the site seems to have changed ... I will ask him for those


Somethin' funny. Any page from is showing up completely blank. Even the "show source" editor window remains blank. (Safari 3 beta and FF 2.0 on OSX 10.4.10).

11  Forum 2005-2010 (read only) / News / Re: Arduino Ethernet! When? on: June 19, 2007, 01:57:51 pm
This is exciting. I am currently on the lookout for a general purpose controller. I had already more or less decided on the because I need network access. Unfortunately, BlueMelon have scrapped their forum, so the "community feel" just isn' there.

The Arduino always seemed more interesting from the support and software/IDE side. If it gets network connectivity, that will make my job a lot easier!

12  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Pulse heart sensor? on: June 19, 2007, 01:25:28 pm
I tried making something like that work, years ago. The IR solution didn't work for me, probably because of the noise level in the preamp.

Finally, I used a small loudspeaker, directly attached to the torso. That proved much easier to filter/amplify and worked very well. The speaker cone was filled with polystyrene, in order to provide a flat surface.

Not sure this will do in your case, but hey, you never know...

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