Wednesday, February 24, 2010

Solid-State Weather Systems Electronics: Part 1

This would be one of the didactic posts I'll be putting here... since we're gonna talk about electronics... but wait.. I can't be serious for a minute! So here we are breathin' and talkin' electronics like we're talking 'bout football (except I DON'T talk about football).

Let's start with the first three weather parameters which doesn't need secrecy: Ambient temperature, humidity and barometric pressure. To newbies in electronics, keep this in mind: DOWNLOAD DATASHEETS OF ANY COMPONENT YOU'RE USING, EVEN IF IT IS A DIODE!!!

Ah, I'd like to note: I won't elaborate too much on the electronic connections and circuitry because Google contains billions of 'em, including crappy ones. The best testimony that can be obtained by an electronics hobbyist is a hands-on experience, so please don't expect things to run smoothly after you've connected every terminals with that thinking that you followed a RANDOM circuit you took from Google is said to be FUNCTIONAL by a RANDOM blogger, so your circuit must work. Anyways, you'll still make that mistake everyone commits: the thought that "the circuit is provided, problem solved." so be my guest, make the mistakes, and you'll learn it the hard way.

Firstly, an LM35DZ is a simple thermal sensor which I used for ambient temperature detection, manufactured and used by the billion, so there's nothing much to it. In stores they usually cost RM5.00 (about 1.50 USD) and Farnell (an international electronics components distributor) offers much better prices.

Figure: LM35 Centigrade Sensor

To anyone using it, or who wants to use it, remember that there is a very important rule: connections! See the figure below:

Note that it is a BOTTOM VIEW!!!! I made this simple mistake and wasted a lot of time so don't mess your sensors!!
So after this, give it a supply of 5V from a voltage regulator LM7805. This'll cost another RM1.50.

Second, humidity sensors... I used HCH1000 capacitive humidity sensor, which is the hygrometer for my weather station and the cheapest by far, around RM26. See below:

Figure: Honeywell's HCH1000 capacitive humidity sensor

This sensor needs to be conditioned according to a circuit provided by the datasheet for HS1101-HS1100 here and the circuit is here:
Figure: Circuit for HCH1000 capacitive humidity sensor conditioning

You'll need to adjust the ratio between R4 and R2 and I added a 10uF non-polar capacitor in series to the HCH1000 to make the response readable by my Digital Multimeter (DMM) in frequency read mode (Buy a good DMM, not the cheap Korean or Chinese ones). Note that it took me a lot of time just to find the right links to introduce these fine adjustments so go figure if yours didn't work.

To test the sensor, put a damp cloth or tissue near the sensor, and the frequency of the timer output will reduce. This frequency'll be used to be translated in PIC microcontrollers (See Deathclaw's intro into microcontrollers in this blog if you don't know anything about microcontrollers here) or you can visit this page: Nigel's PIC page.

Third part: Barometric pressure sensors... I chose the cheapest one, MPX4115A available with a price of RM39.00 by Farnell. This sensor is very simple but the documentation regarding it sucks in the 'net. Don't look at the the datasheets if you're figuring out the pinouts, they'll confuse you with three 'styles' of terminals... see this figure which is painfully extricated from a book by Ibrahim Dogan:

Figure: MPX4115A pin descriptions

This sensor detects changes in barometric pressure, translated in outputs of voltage, so it's simple because its output is from 0-4.8V for a supply of 4.75-5.2v (plug-and-play component, no amplification needed).

For what's worth, I've presented 6 months of research (finding each sensor took a lot of time!!) and labor where the simplicity of these things are evident. Mistakes have been made and rectified, so I hope this'll pave an easier route for weather systems' researchers who wanted to build a solid-state weather system on their own.

Alhamdulillah, all this experience is very humbling to me since the more work is poured, the more I realized how much I didn't know about the complexity and beauty of electronics in the human body (no one has been able to explain why images in the brain, in the region of nanovolts doesn't get mutilated in the presence of even the strongest magnetic fields like in MRI- Magnetic Resonance Imaging machines, where electronic cameras get fuzzed easily with Electronic Jamming devices.) Masya-Allah. This is also the case in weather systems, even with the advancement in technology nowadays, weather prediction are always done with a certain amount of certainty, but it is never certain.

I'll cover the more powerfully complex parameters for the electronics in the next part, which is rain precipitation, wind speed and wind direction. Stay tuned with Vortex Electrica!!!!

Allah has made Vortexes ubiquitous in nature!


Wednesday, February 10, 2010

Verdict: Silver!

Alhamdulillah, Vortex Electrica gained a silver medal in MTE (Malaysia Technology Expo) 2010 for the Solid-State Weather Transmitter.

Personally, I am genuinely very thankful to receive this award since we are undergraduates competing with the larger party of projects done by postgraduates which are far more sophisticated. The 'but' part comes butting in when you can't but feel a bit disappointed with the way the other innovations are being judged in this expo.

I have seen other 'gold' projects which are slammed with only silver or the worse bronze medals (where my university received substandard evaluation, in my opinion), and the reverse also occurred: Projects which are unfit to be called innovation but made their way through the expo. Also, some of the innovations which received 'gold' are an eyebrow-raiser. I'll spare the details to avoid any controversy.

All of what I mentioned are not meant to discredit the judges since my opinion is not the only one which matters, but there are fields where I concede fit to be within my jurisdiction, at least in electronics and structure. I HAVE seen electronics exhibit in the expo which in my kinder words would be said as "redundant". I am totally sure if these projects are uploaded in Electro-tech online (an electronics forum I'm actively involved) they'll pelt these 'innovations' with remarks fit for complaints to moderators, to put simply- they'll CRUCIFY those projects. (Trust me, I have 500 +/- posts in that forum, I know how the Americans and Canadians will respond to news like this)... but don't worry... I won't do it.

Therefore it is highly important we have judges which are not going to be biased; this is analogous to having Pepsi come and evaluate Coca-Cola's latest beverages- of course what you'd expect is "this stuff is nothing much, ours is better 'cause blah blah blah" and all that rubbish.

No offense to any party who felt offended, since there are some innovations which deserved what they got. But I won't say our university were fairly judged except mine. PERIOD.

If any MTE 2010 JUDGES read this, and felt this article is a face-slammer, just take it as a feedback not from me, BUT FROM MY SUPERVISORS!!


Wednesday, February 3, 2010

Surveillance Sentinels: Recycletronics

Did you know that mountains are assigned to the most skilled sentinels? They look out in far, and report in silence using signals oblivious to anyone else except their clan. This is one of the most popular combat tactics' topic: intelligence. But fortunately, we are just waging a war against our own superiors who needs the job to be done. (Wink)

Also, snipers (who may reside in mountains) have additional senses: that humidity, temperature, wind speed and direction or even the earth's centrifugal force (Coriolis Force) is in the mind when aiming at a target.

Here's my picture of the mobile weather station for the MTE 2010:

I heavily improvised the structural part using scraps like telephones, bicycle chain, CD-ROM drives, radio parts, Norslan incandescent light bulbs thrown by my father (if you can't see a trace of it you really need a pair or glasses with the size of an aquarium-just joking guys), marker pens, CD platters, a good amount of screws, some epoxy glue and shafts from printers. This is also a concept in do-it-yourself (DIY) I'd like to promote: Recycletronics and as I coin the term, I'll be heavily featuring this concept through my artcles in the past (see my article on battery packs!!) , present (you're looking at it) and future. The complete structure will be unveiled in a final article on this prototype.

I admire both of the aforementioned concepts , therefore I will elaborate a bit more on weather surveillance:

Most weather stations are mostly mechanical in existence, therefore vulnerable to a lot of factors like extreme conditions and wear-and-tear effect. Also, electronic solid-state equivalents of such systems are very costly. Remember the mercury barometer and thermometer we used to have in secondary school? Scrap that, because solid-state electronics is making way!

The challenge is to reproduce this system with minimal resources for various applications like agriculture (farming precision: raindrop monitoring for precise use of additional water for crops, humidity regulation, etc), events’ planning (wind speed and direction for launching airborne systems, atmospheric hazmat conditions), early warning system (vortex and storm prediction), environmental studies (monitoring system for solar output, wind, and water quality, hazardous materials carried by wind) and so on. So basically the more access we gain over our surroundings, the better it is for ambient precision controls.

The techniques on solid-state wind speed and direction reading features latest improvisation using lower-cost resources with comparable sensitivity as opposed to the sonic technology featured in more advanced and costly designs.

Some details regarding structural characteristics and electronics are discovered and is a genuine implementation of some discoveries, which is true for the solid-state wind sensors, and the rest are mostly improvised, with a small amount of plug-ins to complete the design.

There'll be another article on how I built some of the sensors, so stay tuned with Vortex Electrica!

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