For the Electrical Department's consideration (Lecturers and Students alike)

Assalamualaikum to all Vortex Electrica fans.

One of the problems faced when we, as electronics/electrical students do projects is that very little practical environment pervades within the department. Aside the fact that we all have laboratories, an electronics store to distribute components with the permission of supervisors, some geeks carrying around toolboxes with some perfboard circuits inside, there is still so much to learn regarding electronics.

Kudos to the current Head of Department of Electrical Engineering for making changes to the department, for a lot has changed for the better then, and it is time to move on to further our experience in doing circuits and introduce some tweaks as well.

So how do we start?

For ambitious students, a full fledged tutorial on PIC microcontrollers is the best way to go around it. However we must account for students who are only willing to do simple projects which will make them appreciate the beauty of electronics. And most students are unwilling to spend much money on buying components.

I am not saying my suggestions are the best, but for a lot of subjects, very valuable experiences can be provided to students who do some projects which pertain to the subject itself. Electrical students are divided into four, in my experience:

1. The ones who just want to finish their degree and nothing more

2. The ones interested in doing projects in hardware form (electronics, power, etc.)

3. The ones interested in software/programming

4. The ones who are not interested in anything.

The second and third will be our discussion.

This is the layout of Universiti Malaya's Electrical Engineering curriculum (download the file for a complete listing) which can be used as a medium to do projects:

First year

1. Electronics 1:

-Construct a temperature sensor using an IN4148 diode and some transistors, best marks goes to the ones who manage to linearize the output of Temperature versus Voltage (and the hardware can be passed for further research on low-cost sensors). Should cost only RM10.00 max.

-Drive a relay using different transistors, a report can be done with each team using different transistors, response time, backward EMF study due to relay chatter, how to suppress relay chatter, etc. Costs perhaps RM5.00

-Build a bridge rectifier (Reaaaaaalllllllly frustrating when EE students don't know how to use a damn diode, OKAY!!!) for AC signals. The best marks will be given to the ones with lowest drop-out voltage, and fastest response time, with lowest ripple, and so on. Cost? perhaps RM3.....

-Build a H-Bridge to control motors using transistors. Best marks to the ones who manages lowest drop-out voltage, highest input/output current ratio, efficiency, etc. Each team will use different transistors, zero marks to duplicate circuits. Cost?.. I think RM15.

2. C++ Programming:

-Change it to C programming, and let 1st year students blink an LED or two at the generic PIC main boards. Using a PIC12F and some perfboard, the circuit can be completed in one day, costs at most RM 10. More advanced programming? Drive a motor speed using PWM. More? Interrupt. More? At your discretion.

3. Digital Systems

-Build logic gates using diodes/transistors. Each team will be assigned to different types of diodes, and different gates as well. Cost? Less than RM5, assured.

-Learn to use Flip-flop ICs/Logic Gate ICs and do some applications. Cost? Less than RM15.

....And so on.

2nd year

4. Electronics 2:

-Amplify signals from the heart using any type of sensor. Cost: RM 20. Best marks go to the ones who manage the best accuracy compared to a standard ECG.

-Make different types of filters/instrumentational amplifier using op-amps (SAY NO TO THE LOUSY 741 ICs!!!) Cost: RM 5

-Process signals from various sources using a software in a PC. Like quantifying heartbeat signals, bird calls, light intensities, temperature, and so on.

-Build an oscillator using op-amps.

.....And other millions of op-amp projects.

5. Instrumentation

-Start using PICs to drive motors, detect readings using ADC, display signals, use temperature signals, strain gauges, range sensors like IR diodes, RF modules (315 or 418 MHz ones), drive relays to operate a 30V motor, for instance... and so on. This project has most options actually. Cost: From RM 20-100.

6. Electric Machines

-Build motors... Now this is very fun. Different motors for different teams, so students can build stepper motors, DC brush motors, brushless motors, relay switches, alarms, etc, anything which requires electromagnetism and mechanical motion. We managed to introduce this culture during our 2nd year. Voila!!

3rd Year

7. Electromagnetic Theory

-Build RF modules. Longer ranging, the better. Give some restrictions: Doesn't introduce interference to the existing signals (otherwise it'll jam things up), low power, and so on.

-Build inductive current sensors, like the ones used in Power Electronics Labs.

8. Microprocessors

-NOW.... proceed to using higher quality PICs and give 'em any kind of project which involves sensors, robots and whatnot. Too many projects are on the 'net. Build a frickin' Asimo if they want.

9. Energy Conversion & Power Transmission

-Again, we manage to be the pioneers of projects involving generators. We can settle down with the DC/AC generators, or also explore Solar Cells, Wind Power Turbines, Thermal Energy, and so on.

Example: Make a portable battery charger using a small water tank which is heated up to propel a turbine to charge a cellphone. Campers can use it when they're going in jungles, so when they make bonfires, they also can charge their cellphones. Also, with solar cells too.

10. Feedback Control Systems:

-Aha.. there is so much we can do around here. I suggest: Build a coffee-maker using stepper motors, which need to be modeled using Laplace/Fourier/Z Transforms. This utilizes transient responses of the motors as well. Usage of PICs required.

Also, we can build a simple pick-and-place robots using PICs and servo motors too.

11. Power Electronics:

Build your own buck, boost, buck-boost, Cuk, and so on Regulators. Is it so difficult? We'll never know if we don't try. The problem is many EE students don't even understand the meaning of Power Electronics.

There is one very interesting circuit:

It demonstrates the usability of a nearly dead cell to power up an LED! Therefore it 'boosts' the voltage, demonstrating the significance of power electronics and boost circuits. This project can be assigned EASILY!!! So why do we hesitate in giving students such simple projects?

In conclusion, look at how much projects can be done with just Googling around. To the ones who think it ain't important, I'll just ask one simple question: What do you remember during lectures? Even for a geek like me, I remember nothing except jokes from lecturers!! BUT I remember nearly every detail of projects done by our Team VORTEX ELECTRICA, and it is the memory which made me value the experience in the University. I'm sure all the other members felt the same way.

I hope future Malaysian students who take up EE in any university will ask their lecturers to give projects like these. They're fun and most importantly, life is a lot about memories, and this is an experience which will be hard to be obtained in the times you are already working.

And oh, if you're going to bitch about cost of the projects, remember that you have spent more on food in a single day than most of these projects! So to the lecturers out there (if you're reading this) just give the projects to them and you'll be surprised how capable Malaysian students are actually! This SHOULD be the main part of the continuous assessment for the students. Honestly, I'd put 30% on projects, and 10% on tests/assignments. The rest is exams, and it's fine by me. To me, all that mattered during my tenure (academically speaking) in UM are three things: Kind lecturers who demonstrates "formidability", the three projects in hardware form assigned by lecturers themselves, and finally our final year project. The rest will be very scantily remembered, sorry to say, even the labs and equipments don't mean much to me except the times I actually needed it.

Vizier87 is signing out.

Solid-State Weather Systems Electronics: Part 2>> Acoustic Disdrometer Rain Sensors

Hi guys.. I've just finished my thesis project documentation, now I'm taking a break in my home. This is the next part from my final year project in this blog, a continuation from the article: Solid-State Weather Systems Electronics: Part 1

Where the first article has the least difficulty regarding detection of three weather parameters: Ambient temperature, humidity and Barometric Pressure.

---------------This article has a moderate difficulty level in construction.--------------

Remember that the documentation regarding this article is pretty scarce, since most of the sensors out there are tested using million-dollar equipments, therefore they are patented technologies. I'm just doing this project from a hobbyist perspective... so if you manage to build an industrially-challenging one, good for you! References in the internet regarding rain sensors can be done by yourselves, but I'm gonna put forward ORIGINAL research and WORK done here... and the RESULTS are all original as well... So hopefully we're not part of useless Google searches regarding DIY Rain Sensors.

So.. We have come to the next parameter, which is pretty complex to process, but the hardware required is pretty simple. Yep, we're gonna do a rain check here.. So what is the importance of reading rain? Not important at all, if you are a common guy, but it may have a lot of significance to a farmer who wants to monitor his crops for farming precision. Remember that agriculture is a very-very important field in Malaysia, where a paddy field in Kedah,Malaysia will certainly benefit from precision in rain-reading, Insya-Allah.

First things first- how do you sense rain? How do you know if it's a torrent or a drizzle out there when you're sitting in your home snoozing or drinking milk tea? You know the answer, but it is difficult to answer it using technical terms. So I'll do my best to describe what I'm doing here to a layman.

There are several techniques used, apart from the standard but disgustingly bulky rain gauges (if you don't know about rain gauges you can do a quick wiki here.)

As for rain detection, the following electronics solid-state designs are briefed after processing the 'net's worth of info. NOTE: There are surprisingly very little amount of documented projects regarding DIY rain sensing.. so the combination of info is siphoned into a useful collection of info, hopefully... :)

i) Drop count: Water drips from an orifice that produces drops of known size which are
usually counted optically (which means the usage of optical sensors like Infrared, or light intensity fluctuation detection>> How to imagine the function: It's like seeing a mutilated image of a person at the back of an aquarium, since the water produces aberrations in the light... oh well that clears THAT.). This design is good for light rain, responds quickly to the changes, but requires a reservoir be maintained at a certain level. Ain't good if you're measuring light rain.

ii) Optical rain gauge: This technique uses scintillation effects to detect/calculate rainfall. This
is an electronic solution which is very pricy, since optics requires a lot of complex analysis. This
design is good for rates, but it is easily deceived by fog and mist. Used by Malaysian weather researchers or whatnot MOSTI... The concept is similar to the one used in the drop count. Xenso (A company making sensors) sells them at $99 (RM 300) to 'em weather guys in Malaysia.

iii) Self-siphoning capacitance gauge: This contraption uses a collection tube with a level
gauge, which is self emptying. This is a good method for measuring rainfall accumulation, which not good for light rains. Hard to DIY. No explanation needed since I don't understand it anyway.

iv) Doppler detection: This method uses reflected microwaves to determine intensity. This is an electronic solution which requires a high level of technology, meaning high cost issues. Even I could find much documentation regarding this thingy. Again, I still don't understand it too.

v) Ultrasonic sensors: This method is also an electronic solution, and also very pricy. It
measures rain by detecting the interference signals generated by the raindrops in an array of
ultrasonic network systems. EXTREMELY hard to DIY. And again, I don't understand the details much too. :(

vi) Disdrometers: AHA!! Bingo!! This concept uses impact of rain, where rainfall is measured by detecting the raindrop impacts via a piezoelectric sensor, which produces a voltage proportional to the volume of the raindrop. Used in the $3850 WXT510 Weather Transmitter (You're a fool to not sense a hint of sarcasm in this sentence)

Heh heh.. But this last option above proves to be the easiest to reverse-engineer and DIY, since Vortex Electrica is ALL about saving money and still being able to do kick-ass projects!! Credit needs to be given to Rolf Hut in his Instructables project.
The details regarding the electronics and techniques of detection are original, from Vortex Electrica though.

So.... what are DISDROMETERS? It is a meter which detects impact, simply put. A raindrop has impact, therefore a disdrometer reads it. The simplest analogy I can give is: Imagine a microphone being tapped by your finger. What does it produce at the speakers' end? TAP! TAP! TAP! Similarly, when you're sitting in your room, you know whether it is raining heavily or not. Now... to make it analyzable and quantifiable... we're gonna start on the construction:

STEPS IN BUILDING A DISDROMETER:

1: You'll need:

a. A plastic CD/DVD platter (or something flat, take your pick)
b. A piezoelectric transducer, like shown here:


......which can be scrounged from broken telephones, or broken clocks or.. anything which produces monophonic sounds.

c. Some electronic components, which are pretty simple:
a) an op-amp IC like the LM358 or LM741.
b) A potentiometer
c) A schottky diode
d) A donut perfboard.. of course.

2. Glue the piezo transducer to the CD platter using EPOXY GLUE.. very important. The one I did looks like this:

3. Construct the rest of the electronics according to this picture:


This is called signal conditioning... where the output spike is isolated from the rest of electronics by freewheeling the negative spike voltage produced by the piezo transducer using an IN5817 Schottky diode, where it is a diode with a forward voltage of 01-0.2 V only, where a lot of op-amps can only withstand -0.2 inverse voltage at it's non-inverting input, and also the signal is amplified by the gain setting using a single potentiometer. If you don't understand, never mind, just build the circuit. :P


4. The finished product in my project looks like this:




5. Now, you can at least observe the output from a location by placing a voltmeter between the output terminals of the circuit. The output is with regard with the raindrop volume, the higher the volume of the raindrop, the higher the output.

Quantification and calibration techniques will be dependent on the transmission of the data to a PC, where we can utilize the full power of a PC computer to do an acoustic analysis of the signals of the raindrops. We'll cover the data conditioning in further articles, since it is a fully different entity of hardware which needs to be discussed, which is also pretty complex.

Conceptually, the area under the graph depicts the raindrop volume, shown below here is me testing my disdrometer (The graph can be predicted according to the typical output shown in the oscilloscope):

The cost of the network is only around RM4.00... impressively cheap if you're daring enough.
For now, enjoy seeing the output which comes out when rain hits the drum!!
In the following article, we will uncover my most difficult part, which are solid state wind sensors, or anemometers, also built by myself, also with not much documentation in the 'net.

See ya all real soon, InsyaAllah.


Regards,
Vizier87