Solar Scare Mosquito

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Every year, over a million people are killed by malaria. The only solution to this problem is to destroy mosquito breeding grounds and curb the problem at source. As mosquitoes breed in stagnant water, I concluded that surface aeration would be one of the best means of eliminating breeding grounds.

So I built a device that generates air bubbles at regular intervals and effectively produces ripples up to a radius of 2 meters (sufficient for most urban water bodies). The device automatically switches on when it comes in contact with water an alarm alerts if the water body dries up or someone tries to remove the device from water. At less than $10, the device is cost effective and being solar powered, it is energy independent and maintenance-free.

Here is my Youtube project presentation: Solar Scare Mosquito

Note: You will have to see this video to fully understand and appreciate the project.

Check out this blog for similar cool projects:

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Step 1: Hypothesis

More than half the world's population is vulnerable to vector-borne diseases. These diseases, namely malaria, largely affect children and poor people and there is no promising solution to eradicate it.

Question: So how can we control malaria using technology?

As mosquitoes transmit malaria and water stagnation is the primary cause of mosquito-breeding, by preventing water stagnation, it should be possible to curb malaria.

Hypothesis: By devising a surface aeration system for small water bodies, it should be possible to control mosquito breeding.

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tedsavior18 days ago

May I ask how you conducted your observation? How were you able to determine the larval population?

gallactronics (author)  tedsavior17 days ago

Well the pool in which I conducted the experiment was fairly small. So it wasn't hard to make an approximation of the larval population in there. This is far from a scientifically sound experiment, but serves the purpose.

Dave Kruschke2 months ago

Your Step 4, above, admonished me to "Get my Hands Dirty" so I took you up on it. I didn't believe that the resistance of the water would be low enough to turn on your middle transistor to supply 200 ma of current that I think is needed for your pump motor. I used four resistors in parallel to simulate the load of the pump at 6 volts, drawing 200 ma of current. Where my 100 ohm resistor is, I had put in a variable resistor and adjusted it lower and lower to get the maximum current. The highest current I could get with new batteries was 123 ma, less than 200 ma. I measured the resistance of the variable resistor and got about 100 ohms. I then replaced the variable resistor with a 100 ohm resistor. So..., IF the resistance of the water between the pond probes was 100 ohms, there would be 5.2 volts at 123 ma to power your pump. Please review the attached schematic.

But now the problem: When I measured the resistance between probes put in tap water, I got 1 megohm, way, way too high to turn on your transistor. Next, I mixed up a very salty batch of salt water and measured 100,000 ohm - still way, way too high to turn on your transistor! Moreover, I don't know if the mosquito would even deposit larvae in salt water.

So I'm convinced there is no way that your water probes are going to turn on your transistor that supplies power from the solar cells to the pump motor. You might need one or more additional transistors to your turn on circuit for your pump. Since your turn on circuit for the piezo buzzer uses a lower turn on current and has two transistors, it may behave better for you but I didn't check this out...

Mosquito power test.jpg

Try using a FET instead of a bipolar. They run on voltage and the impedance is really really high. You will probably have to put a resistor (megohms) shunting G-S just to get it to shut off when you take it out of the water.

Yeah, the FET suggestion above might be part of the solution to the motor turn on problem. However, I read that the famous MPF102 FET can only carry a max. current of 20 ma, enough to turn on a LED but not the pump motor. So this FET might still need a bipolar transistor.

I think that this project has more than a couple of rough edges to be worked out before any kind of "victory" can be declared. Of course, I'm assuming that it is expected that this project actually work and cost as advertised for some kind of specified time...

The MPF102 is a small signal UHF amplifier junction FET. What you need is a power MOSFET. They have replaced bipolars almost everywhere. You can control dozens of watts with a few volts of gate voltage. E.g. the "famous" IRF510, 5 amps, blocks 100V, costs under a buck.

Well, Jim; did you actually try this or is this just something "off the top of your head?" I paid well over "a buck" for the famous IRF510 from Radio Shack and hooked it up to a 6 volt supply and a 6 volt bulb that draws 150 ma. Since the bulb dimly lit with nothing applied to the gate, I grounded the gate with a 10 megohm resistor, following your earlier suggestion about doing this when using a FET. Using high ohm resistors, connected between 6 volts and the FET gate, I had to work my way down as far as 100,000 ohms to get the bulb to turn on (but only partially). But LESS than 100,000 ohms wouldn't be good here because of the higher ohms inherent in a water probe connection.

I suppose you could accuse me of having a "bad attitude" but in my case, this is caused by published suggestions that are untested and don't work....

I suggest you do some reading on MOSFETs in general, and switching and driver circuits in particular. This might be a good start:

As I said, one of the tricks of the MOSFET vs. the bipolar is that at low switching speeds you only need enough energy to charge up the gate capacitance to a few volts, whereas the bipolar needs a constant feed of current to stay on. I liked to use them as relay or lamp drivers (back in the incandescent days) fed by 5 volt logic, which sees a minimal load. I've stacked them to make 1200 volt pulses, driven by a pulse transformer. I've used them as circuit breakers that react in a microsecond.

Since you've got an IRF510, get a data sheet and look at the curve of drain voltage vs. current at different gate voltages. They don't start to work until you get to the gate threshold voltage of up to 4 volts, but at 6 volts they should be able to pull a couple amps.

Radio Shack is handy, but you can get them on Ebay for around 50 cents. Be careful with the gate, because you can zap them with static a lot easier than bipolars because of the super high impedance.

Thanks, Jim. I think that your suggestions are good since actually using MOSFETs is new to me. But after further thought, I can now see that it would be more appropriate if YOU were the one that carried water for Pranav (a.k.a. Gallactronics) by providing a schematic here that could be deployed to control his pump according to the presence of water. Of course, the above assumes that Pranav is still interested in this project...

In my own case, my Instructabe time lately has been centered on Instructables related to the "Joule Thief" along with touching on RFID.

Well, I'm busy saving the world in other ways, and I think that Pranav has a pretty good working model. His circuit seems to work pretty well, and the 2N3904 or 2N2222 sells for 2 cents in bulk and there are billions of them out there, vs. a 25 cent MOSFET that can be hard to find. We don't know how much current his pump draws, or the bulk resistivity of scummy pond water in India, or what he used for probes to get enough drive current.

Of course his water bubbler is only going to work on a certain size body of water, and looking around my neck of the woods I find it would be completely useless to me. So I'm going to build some bat houses and maybe a guppy pond instead.

Pranav should be quite happy with your post above as it reveals much Trust but little Verification. Fifteen years of experience in the Engineering Quality field has maybe pushed me to being more critical than others here. Trust but Verify is what I'm thinking here.

For instance, you say "we don't know how much current his pump draws." But actually, we do have some idea of a minimum. Going online, I was only able to find pumps powered by 3 volts, 12 volts or line voltage. The lowest (and cheapest) was rated at 1.5 watts. So...o, at 6 volts, we have 250 ma, sort of what I've been using as an estimate. Do you think I'm wrong to think this? And another Trust issue is Pranav's image where a Duracell Alkaline battery is shown but it is tagged as a rechargeable. Additionally, Pranav's scummy pond water that you mentioned probably has a higher resistance than the batch of salt water I made for a test.

Even though Pranav has written what is supposed to be an Instructable here, he has left out details needed for Replicating his device. I've always thought that Instructables were about Replication not just about Publicity. Moreover, notice how Pranav avoids providing Input that would easily clear up some of our endless questions. However, Pranav does respond to Praise but I don't think that this will qualify him for any kind of financial grant.

Lastly, do be cautious with Bats as about 2 to 3 people a year die a horrible death in the US due to Rabies. Before and When I was growing up, Bears, Wolves and Rabid Bats were to be feared but now this has all changed as the current generation seems to think that these creatures are "cute"...

A Bat - watch out.jpg
gallactronics (author)  Dave Kruschke1 month ago

Sir, I respect your "Fifteen years of experience in the Engineering Quality field" and I appreciate your in depth analysis of this Instructable. But to let you know, I am a college student with a modest knowledge of electronics and little free time.

I agree that this device is far from being an engineering marvel. But the difference between engineering and innovation lies in the fact that the focus is on perfection of design in the former, whereas in the latter, the focus is on the idea and the underlying concept.

And in the case of the Solar Scare Mosquito, more than the device itself, it is the underlying concept which is being appreciated globally.

I agree that there are some glitches in the circuit but I don't have the time nor the knowledge to perfect it.

It is up to old hands like you to resolve these issues!

My experience in Engineering Quality was not mentioned to claim any Authority. I only mentioned my Engineering Quality experience to possibly explain my being picky about certain details that seem to be needed. You didn't mention WHAT you were studying in College but I do suggest that you don't over emphasize what you call "the difference between engineering and innovation." Was Thomas Edison, who invented the practical light bulb, record player and movie camera an Innovator? An Inventor? An Engineer? A Businessman? Maybe all four? The important thing is that Thomas Edison took Ownership of the problems he worked on and badly wanted to see them work. Some of your readers might or might not help resolve your issues but it is very unlikely that they will take ownership of your project. That said, I do respect the fact that you are short of time but I suspect that your knowledge about your project isn't that far from what is needed to make it practical...

As to your not knowing about Mosquitos and salt water .. Yes some do ,and will only lay there eggs in water with 1-12% salt content .. Anopheles Atropos is one species . Aedes Taeniorhynchus (Salt Marsh Mosquito) is another

Congratulations!!! for winning double contests :). Great job done :)

jimvandamme1 month ago

I just remember another circuit I built that controlled some relays from 28 volts DC. I used an automobile high side switch IC similar to this one:

The IC has a level shifter and charge pump that generates the voltage above Vdd needed to turn the N channel FET on. N channels are cheaper than P channel, but you need that boost circuit to make a high-side driver in a negative ground system. Another cool FET trick is that some of them have a tap off the main chip that gives you a current sample, so you can measure the current, make a feedback loop, or detect faults. This chip runs a few dollars but has a lot of handy things integrated on the chip.

Another FET I've used by the boatload is the VN10KM, also branded the VN2222 (to replace the equally popular 2N2222). It's lower power, but pretty much hard on at 4 volts on the gate. They'll run 300 ma, but you have to be careful about the on resistance (5 ohms) generating heat. There's a little heat sink tab...

I've recently read about a shift in attitude about publishing new and novel methods for solving certain important problems. What's happening these days is that more solutions are being published that lack critical testing to verify that the solution actually works. Is it no longer important that a new method actually work, especially in an INSTRUCTABLE? In this particular Instructable, I notice that many of the "posts" here seem centered on cheers and accoclades for Pranav (a.k.a. Gallatronics) rather than questions about important details needed to make this project actually work. I mean, Pranav has time to acknowledge the cheers and accolades but leaves questions about critical details unanswered. In my own case, I think of the Russian Proverb, "Trust but Verify!"

I cheer Pranav's innovative effort but hope that his project can proceed to some kind of completion that makes it worthy of deployment...

This is a great idea. I would like to say that you can make this cheaper. Remove the air pump and replace it with a vibrating motor.

Omtoria1 month ago
This is a pretty cool idea... One of those moments where you think "dugh, that is so simple why hasn't anyone come up with that yet"! I can say from having studied biology and urban pest management that modifying a pests environment to prevent either the ability to breed or fully develop is one of the most effective ways to eliminate and control a pest population. Just a thought, but in terms of a more commercial application would a very small solar panel on the top be more reliable then the rechargeable battery (especially if you wanted to leave a few hundred of these around an area and not have to pay a technician to check them all on a regular basis for battery drainage).

Might be time to get your patent before someone else becomes a millionaire off of your idea!


He would be wasting time on getting a patent. Time isn't money with something like this, it's life.

Congratulations this can be a great help to Africa.

If you are unfortunate to catch malaria in Asian countries, a local weed -Pronounced (Mudwatt) is available everywhere, ground -up without heat and drunk cold, it reduces or eliminates malaria. (This was the secret weapon the Vietnamese used in the Vietnam war. The curative feature is a hydrogen peroxide chain that attacks the malaria in the body without normal damaging effects of its commercial counterpart.

It sounds similar to quinine which is found in tonic water. It is made from tree bark and was originally used to treat malaria. And then people apparently found that it also tasted good with gin.

The amount of quinine in tonic water is not nearly enough to kill or prevent malaria. You'll need to drink about 10 gallons of tonic water per day to get the right dose of quinine. Quinine itself is also not good for your heart.

LobosSolos1 month ago

Congratulations on catching Bill Gates notice.

djow1 month ago
Congratulations Pranav! I think your idea would be very useful here in Brazil. We have a lot of people dying every year contaminated with dengue virus. Probably the costs to produce your machine here would be superior than $10, but still cheaper than other options.
neilcp1 month ago

God bless you Pranav.... this is fantastic.... really proud of you buddy.... I just know that this can save thousands of lives, especially in our developing countries....

Excellent Bro :). Proud of you.

gallactronics (author)  Tarun Upadhyaya1 month ago
thebeatonpath2 months ago

This is ingenious! Good job!

karthik872 months ago

Hey buddy did you check this out, its cool :-)

gallactronics (author)  karthik872 months ago
Wow! Thanks for sharing this. Bill Gates' Tweet about my project is very encouraging!

is anyone willing to build this for me? I'll pay you to do it but i just am not savvy enough to make this and i need it for my dog pool!

blackwing012 months ago

great idea..a simple solution to a big problem

I think that the idea is very creative but needs much further work on related details before I would call this idea "a simple solution to a big problem." Anyone funding a project such as this would want to know: Does ALL of it really work as advertised? What would the cost breakdown be for, say, 1000 units? How long would these devices work? There is a saying in Engineering, "Design something for a lifetime, and it might not last five years. Design something for five years and it might last a lifetime..."

smooney22 months ago
This is a great idea , but the its kind of misleading. Yes this will help in making the water less still ..
You get Malaria from Anopheles Mosquitos , which tend to live in aquatic vegetation , where this would have no effect.Most larvae tend to sit in the water at about a 45 degree angle and there air tube looks almost like a star and they use the surface tension to hold themselves in place.. Anopheles sit horizontally on the surface with the aid of palmate hairs , they hide in vegetation to hide from predators . Gallatronics you are a genieus for coming up with this , but it would more along the lines of helping with West Nile , EEE , and SLE...
gallactronics (author)  smooney22 months ago

Interesting...I had read about Anopheles larvae sitting horizontally on the water surface but I did not pay heed to it. So yes, this device would actually be more effective against West Nile and SLE.

Thanks for the input!

Gallactronic.. Here's a video from Walt Disney 1943
The EPA would have a fit with the putting stuff in the water part but the rest is good . Now we use Agnique instead of oil. But it's mainly used to kill the pupae ,towards the 4th instead the larva no longer eat .
gallactronics (author)  smooney22 months ago

LOL... Though prehistoric, this video is very informative and interesting!

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