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Messages - Rubu

18
General discussion / Re: 5V 16x2 Character LCD with 3V3 Logic
I've had major issues with this, even LCD's that were supposed to be run from 3V were a lot of trouble. Did manage to get them working in the end, with a 4.somethingV for the contrast pin. I really have a love/hate relationship with those LCD's, there's always something wrong with them...
20
CPLD programmable logic / Re: Faster Digital Oscilloscope
QVGA screen + touchscreen doesn't have to be that expensive. I know sourcing from something like ebay is dangerous, but there are QVGA TFT's with touchscreen to be had for 20usd incl worldwide shipping and up.
Also, the LCD of the DSO Nano is listed on seeed for 20 usd, this is without a touchscreen though.

I'd love to help out where I can, definitely will be reading along. I have had university courses on analog and digital signal processing, but not much hands on experience.
21
CPLD programmable logic / Re: Faster Digital Oscilloscope
Interesting discussion going on here.
I think the most important thing when using a scope, is know what exactly you are measuring. In other words, when well aware of the limitations of your set up, even sampling at only 2.5x the base frequency might prove useful.
Naturally, when measuring a 10Khz square wave sampled at 25Khz, you're not going to see a square wave on your screen. However, this might still contain useful information to you, depending on what you want to 'learn'.

Anyway, I really like the idea presented in the topic start, curious to see if/where this will go!
23
General discussion / Re: Site update changes and bugs
[quote author="pietja"]Today i got a strange problem with the homepage, with both the latest FF7 beta and IE.
Both side bars with the Categories, Recent Comments and the rest are at the bottom of the page under the main blog posts.
[attachment=0][/quote]

Same problem here, Google Chrome.
24
General discussion / Re: Farnell for the Dutch guys
You can export the cart, en attach it to the mail, if you also send some proof along with the bank transfer over the internet, you can have the order at your doorstep the very next day, It's really pretty smooth if you know what your doing.
25
General discussion / Re: Farnell for the Dutch guys
I've used it a couple of times, one requirement though, that is not mentioned here, is that you have to be home for the delivery, it's in the requirements (a .doc file somewhere on the site) this can be troublesome, but other than that it's usually smooth sailing.
26
Project development, ideas, and suggestions / Re: Re: Web Platform v2?
I've been working on routing the Linux Board_20110405.zip and I think it's pretty much finished now. It has no airwires and also no DRC errors with Seeed's dru.

I don't have a lot of routing experience so i'm not sure how useful it will be, I mostly used it to get familiar with Eagle as I will be using it for a project i'll be doing next year.

I tried to make the power traces a little wider and attempted to keep the right angles in traces to a minimum. I'd be very thankful if someone can give me some feedback, general tips, guidelines, on PCB routing.

Tell me what you guys think!
27
Project development, ideas, and suggestions / Re: BusPirate interfacing MMA8453Q
Impresive soldering indeed! I actually used the BP for the exact same chip, but had some PCB's made for the board. Still wasn't easy to solder considering I only had a regular iron at my disposal, but I still managed to get them on quite nicely. I extended the pads to the outside of the package, tinned the pads on both the package as the PCB, and soldered them on with a lot of flux.
[attachment=0]
Great chip by the way, I've got a couple of units left,so I'll definitely be doing something cool with them!
28
Project development, ideas, and suggestions / Re: Design challenge: ultra low power
[quote author="octal"]check these http://www.energymicro.com/technology/  (32 bits ;) )[/quote]

Are these available yet? Can't find them, they look promosing!

[quote author="brian"]Arhi is correct, if you can find a way to "save up" power that is allowed.

However remember you only have 2 V as well and so many chips that require 3.3 v etc are off limits without a step up conversion or similar (voltage doubler using switch caps for instance).[/quote]

The energymicro chips octal linked can run on a minimum of 1.8V, and at least some of the MSP430 chips are capable of running on 2V too.
Also, if the 2V source is a battery with a big series resistance (like most coin cells) charging and discharging a capacitor as a buffer doesn't sound half bad!
29
Project development, ideas, and suggestions / Re: Design challenge: ultra low power
There's a pretty new MSP430 Line, with "FRAM – Ultra-Low-Power Embedded Memory" the MSP430FR57XX Series. These supposedly use about 100uA/Mhz. MSP430's standby mode consumes <2uA, so if you have the MCU in standby most of the time, you should be able to pull something off at 20uA average. (In datasheet-theory, ofcourse..)
Some digital sensors also have very low standby consumption, I know of at least one accelerometer that states <2uA as standby power consumption. Who knows what could be done!

Edit: The 100uA/Mhz figure is for running at 8Mhz, not sure what it would do at 1Mhz...

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