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5836  Using Arduino / Programming Questions / Re: Comments in Code affect compiled size ? on: April 07, 2011, 08:55:00 am
What does increase increase memory (FLASH, SRAM) usage is if you have Serial.begin(), wire.begin() but don't actually use serial port or I2C bus. Some people start their projects from someone else code and didn't do a good cleanup.
5837  Using Arduino / General Electronics / Re: How do you calculate total EEPROM memory? on: April 07, 2011, 08:37:52 am
Hey if you want a decent sized well-arduino-community-supported EEPROM, I suggest 24LC256 (32KB) and 24LC512 (64KB).
5838  Community / Bar Sport / Can I search a topic under a specific board? on: April 07, 2011, 12:30:09 am
I really want to search keyword like "ribbon cable" under general electronics board but how? I posted a question about IDE ribbon cables and later found the solution. It took me lots of time to dig it up in order to show it to someone with similar problem. Thanks.
5839  Using Arduino / Displays / Re: Artifacts on GLCD? on: April 06, 2011, 11:04:04 pm
Thanks for sharing. The 80-wire 40-connector IDE hard drive cable is very tempting but lots of the 40 connections are connected together to the ground. I discussed this a while back. You will need a 40-wire 40-connector older cable.,54426.0.html
5840  Community / Local Groups / Re: XinCheJian - A Shanghai Hackerspace on: April 06, 2011, 07:37:22 pm
Nice website. With your neighborhood shops, you can make giant arts maybe steel dragons with the help of that welder and some hardware from the hardware store, and cloth from the cotton shop. I'd like to see some Chinese dragon in New Year parades controlled by Arduino, motors and LEDs and maybe head controlled by the dragon ball (video tracking). Would make a big impression on the general public too!
5841  Using Arduino / Programming Questions / Re: rev counter on: April 06, 2011, 06:47:17 pm
You also need to know if the Hall Effect transducer is outputting pulses of 0-12V. You will need to step the voltage down to 0-5V for Arduino to read. Sensing a Hall Effect switch is as easy as sensing a button (the arduino actually can't even tell if it's a button or a Hall Effect switch). Get use some details of the sensor and what display you want to use like johnwasser requested.
5842  Using Arduino / General Electronics / Re: Very weird - touchscreen monitor on laptop kills RFID range on Arduino on: April 06, 2011, 09:58:54 am
Is there any chance the touch screen has an active digitizer? An active digitizer interacts with a special pen. maybe the digitizer is emitting radio frequency to active the special pen. Just a thought.
5843  Community / Bar Sport / Re: Dynamotor on: April 06, 2011, 09:42:01 am
BTW - have you looked up tube testers on Ebay lately? At one time you couldn't give them away; nowadays they're fetching amazing prices - I was trying to find a good one a couple of weeks ago, and couldn't believe what I was seeing, price-wise. Must be all the guitar and audio tube-amplifier fanatics out there...

The responsibility for those high prices on tube testers predominatly comes from two special interest groups. High end 'golden ear' audiophiles that feel the tube based hi-fi sounds better then solid-state equipment. The second ground is the guitar tube amp crowd that use tube amps for the 'proper' distortion sound that such tube amps produce.

Both groups seem to have high disposable income and have done crazy things to the new old stock tube prices and other tube amp components and test equipment. Lots of specialty vendors cater to that market.


"Wonderful". I collect old computer processors not to use them or pretend they are better than the newer ones. But on the same used cpu market, there are gold extractors that want every last old cpu to extract gold. They're destroying environment and jacking up the price for us collectors and not to mention people selling information on how to extract gold from cpu making cpus look more valuable than they are. So same thing, you want it, you can't get it unless you pay unreasonable price, old tubes or old cpus. smiley-money
5844  Using Arduino / Programming Questions / Re: math expressions within abs() on: April 05, 2011, 06:08:33 pm
Sans side-effects.
#define abs(x) ({__typeof__(x)__x=(x);__x<0?-__x:__x;})

Thanks for digging it up from arduino ?? file. I'll be cautious myself when using the function then.
5845  Using Arduino / General Electronics / Re: EEPROM Programmer on: April 05, 2011, 01:22:18 pm
What EEPROM chip? Any part numbers? The UNO should be able to do it with ease. I've worked with 24LC256 series. Not hard at all.
5846  Using Arduino / Programming Questions / Re: math expressions within abs() on: April 05, 2011, 01:14:02 pm
You beat me to it on "macro messes things up", Rob.

I never use macro defs like that. It's just a poor way to construct things with unpredictable outcomes. Always use a function so its parameters get evaluated before the call.
5847  Using Arduino / Programming Questions / Re: math expressions within abs() on: April 05, 2011, 01:12:03 pm
You can always do
y=$var-1 and then abs(y) to be sure. The following from the reference page is just strange:

abs(a++);   // avoid this - yields incorrect results

a++;          // use this instead -
abs(a);       // keep other math outside the function

Maybe the person that wrote the above didn't know  what a++ is supposed to do. If he wants a to increment before the abs, he should use abs(++a).

If abs() is a function, then its parameter is parsed and calculated before the function call is made. End of the story. If the abs() is a macro, it may mess up a little if written improperly.
5848  Community / Bar Sport / Re: How to sell your own ideas on: April 05, 2011, 12:39:44 pm
I see. I thought about starting a business. But for the extent of my limited activity, I'm better off without a business right now. If I do sell more in the future, I'll think about it again. I can write off tax for parts I buy for development, pay myself a small wage for my work and designate a workshop in my house for my home business. I don't have a house yet. I am one of those that pay income tax but don't get to vote so starting a business is more difficult even when I'm ready.

So have you thought about creating some casing or cover for your kits? There should be some local business you could use to do acrylic cutting and else.
5849  Using Arduino / Programming Questions / Re: math expressions within abs() on: April 05, 2011, 12:13:40 pm
I don't know about discouraging math within abs I would just directly translate from Perl. Is $var a string in Perl or a regular number? I don't believe Perl distinguishes integers and floats but you need to define int or float in Arduino C.
5850  Community / Bar Sport / Re: How to sell your own ideas on: April 05, 2011, 11:55:59 am
Thanks for sharing nootropic. Have you paid your test engineers (your kids) for testing your design with games? You should include that in your cost too.

"I've never worked so hard for so little money."

I fully agree. But hearing you deal with tax makes me thing you did make some return from your work to worry about Uncle Sam. Good for you!

I personally don't like packing too much. I'm a bit OCD so I check too many times on perfectly packed kits and always fear I miss a part. I also reuse packaging materials from my own purchase so each package is unique (some had UK or HK stamps on them if you look carefully). It's time-consuming to come up with a different package each time. It's just me. I would mainly go through distributors to ease my brain.

So for those that turn our electronics hobby into a time-sucking, occasionally money-making, but always totally cool and self-rewarding business, good luck to us all!
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