Micro Basics

What do the ADSL Noise Margin and Attenuation Numbers mean? From http://mybroadband.co.za/vb/showthread.php?t=46156 :

Noise Margin (AKA Signal to Noise Margin or Signal to Noise Ratio)
Relative strength of the DSL signal to Noise ratio. The higher the number the better for this measurement. In some instances interleaving can help raise the noise margin to an acceptable level.

6dB or below is bad and will experience no synch or intermittent synch problems
7dB-10dB is fair but does not leave much room for variances in conditions
11dB-20dB is good with little or no synch problems* (but see note below)

Another CDDB for us, Eric Wilhelm announced last month that Instructables is moving to a closed pay-only community model:

Free Instructables users will not longer be able to:

1) View entire instructables at once
2) Print out instructables in PDF
3) View "secondary" images in instructable steps

This means that if an instructable has more than one image in a given step, you will only be able to see the first image, and thumbnails of the other images. If the author left important detail in the images, that information is lost.

I am doing a smoke test of my little wireless video broadcast setup tonight at the local tech group's meeting. If you have a bit of time, I'd appreciate it if you'd watch for a bit and let me know what problems you experienced, or whether you found any value in this sort of thing.

Tonight we will likely have two FIRST robots, a live demonstration of lost foam metal casting (cheap - 5 gallon bucket furnace, etc), and a few other shorter presentations.

It starts at 7pm EDT, and should be available here:
http://www.ustream.tv/channel/adam-davis

I get a lot of "link exchange" requests. I doubt this will prevent them, but it gives me a convenient place to put a recent response I gave to one which I can use as a template later to saver time. Generally I find out a little about both the SEO company, and the company that purchased the SEO services. I then email both the SEO scammer and the company who purchased their services.

In other words, if you are going to request a link exchange, please note that I generally contact your customer directly and tell them how lousy link exchanges really are, and that they are wasting their money on you.

don.neufeld points out that there's only one safe way to use a for loop to decrement an unsigned int to 0:

for( i = n; i-- > 0; )
{
// Use i as normal here
}

"There's a trick here, for the last loop iteration you will have i = 1 at the top of the loop, i-- > 0 passes because 1 > 0, then i = 0 in the loop body. On the next iteration i-- > 0 fails because i == 0, so it doesn't matter that the postfix decrement rolled over the counter."

I needed to be able to evaluate user entered equations, with custom variables, for instance lightvalue*10/(factor*1024) where the two variables are filled in by values in the software when the equation is evaluated.

Eventually this requirement was dropped, but not until after I had built a simple proof of concept program, which I'm putting here so I don't lose it again. The code below and the compiled executable (windows) can be downloaded as well, example.zip (5.5KB)

Compiles under tcc, should be straight ANSI C and is portable, but let me know if you have issues.

When I squatted one of the twitter accounts, I went to the effort of setting up the twitter page to match their website palette, added their logo to the user avatar, set up the links and tagline, and so forth to see how much I could make it a part of their brand.

When they took it over, they didn't change a lot (better version of the logo, etc), so I suppose I did ok. It's cutting a fine line, though, since I am not really a representative of them. I took care not to "follow" anyone on their account, and only made tweets that linked to their website and were obviously directly related.

When they took control of the account, they asked for suggestions, and here's what I told them.

I've started to squat twitter accounts.

There. I said it. I'm a twitter squatter. Sqwitter? Twuatter? Either way, according to myself, I'm the scum of the earth!

Many years ago I ran a business, and considered getting the domain name. A few months after that thought, it was purchased by someone else, and I missed out. I used a different name, but it's far from ideal - I had already built up some amount of brand recognition, and it was annoying to need to compromise.

Domains are so cheap now that if I have an idea I get the domain before thinking about it for too long - if I don't pursue it, I let the domain lapse in a year. I don't consider this squatting, as I'm not registering something that obviously points to another business/person, etc. I simply don't want to end up deciding to pursue an idea and finding that in the intervening time someone else took the name.

In a recent piclist message Jinx mentioned two methods he uses to drive static LCDs, and sent me the following to share. Click on the images for larger versions.

The 16F628 circuit is an up/down timer/clock, with optional dome bell or piezo bomb as the alarm

The two weak pull-ups on the ICM7211 data lines can be put in circuit by the user with jumpers, and those lines are read as '0' or '1' by the PIC, which then enables s/w routines if necessary.

Setting the display is simple - sequentially select digits with the 4017 and the 4-bit data on the data lines appears.

My experiments with backlighting.

I recently saw a cute little, inexpensive GPS module offered at Digikey that includes dual PCB antennas (I assume, maybe it's one large antenna?). The company offering it, Antenova, focuses on antennas, in particular PCB antennas, and I expect this module mainly showcases their technology.

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