Engineers like a list of Projects to work on. Here is just one such list made from the needs of villages in India. Check them out!
Electronic Projects (While the list was written in around the year 1999, I still find them relevant.)
1 A Data logger, 8 channel. Where a ‘chip ‘ is removable and data can be transferred to a PC and processed. We collect various data such as rainfall, humidity, max-min temperature etc. We also want to be able to collect data such as the water level in wells. If we have one person going around different locations and collecting these ‘chips’ where the data is stored for previous 24 hours, we can collect this in a central place and process.
Some of our friends were developing this for some time and later gave up. They had estimated the price at `Rs 1500 max. We could also use this for other development projects such as drying, baking etc to see the rate of drying or uniformity of temperature etc.
2 Electronic fuse. Many of our people have the habit of putting a bigger size fuse wire if it blows repeatedly. Also it takes a long time for replacing. An electronic 3-phase fuse would be useful to farmers for water pumps. We had built a single phase electronic fuse. But we could not build 3 phase for power supply.
3 We make a DC tube circuit, where using only diodes and condensers we get a pulse of 600 V DC and this is used for lighting 40 W tube lights that have a burnt out filament. We have put back in use many such tubes (over 200 till now). We give this as an exercise to students. However we find some burnt out tubes don’t work and some do. We do not know how to s select the tubes from the junk tubes.
4 A Power-off meter. Our power supply goes off frequently. For our control purposes it will be useful to have a record of when the power was off- the total time during an interval. We tried an electric watch where the power was supplied through a relay, when the mains power goes off. This gives the time but not as hours. We tried to make a recorder where we fixed a chart on the hour hand of a clockworks unit. This works but the chart has to be changed every 12 hours. This was given as a project for a dropout girl.
5 Electronic fence. We wanted to protect our farm from stray grazing animals. Fencing is very expensive. So we used a timer circuit, and connected an ignition coil. This gave a short pulse of high voltage for a fraction of a second, and repeated at desired frequency. This worked fine on dogs and sheep. We did not test on cows. The animals learnt within 2-3 contacts and then do not go near the wire fence. But the people who own the animals come and damage this so that their animals can graze, in this area. That is what we want to prevent.
6 Water table alarm for wells. Farmers have wells where the water table goes down below 9 meters and then the pumps don’t pump out water. So they lower the pumps on a hanging platform. When the rains come, the table rises, and some times it floods the motor and they have to rewind the motor. This happens every year. Some alarm to indicate a rising level would be useful.
7 Dairy, milk collection centers, often get milk, which sours and has to be thrown away. When they do not know which is good and bad, they mix milk from several farmers. Then the good gets spoilt by the bad one. Souring of milk is tested by the time taken to reduce the colour of a dye, (Methyl red) If we could use an electrode to measure the redox (oxidation-reduction) electrode potential of the milk, perhaps this could tell the stability status of the milk. By not mixing good with bad, we could save milk.
8 We make an earth resistivity meter, for locating underground water. We have used it effectively for 17 years. We make the instruments and sell it to other agencies and also teach them to repair and maintain. It works on a 4 Hz 18 volts generated from dry cells. It gets interference from high-tension power supply cables if they are over the land we are testing. In some cases where it possible, we do the Vertical Electrical sounding when the power is off. But this is not always possible. These lines induce frequencies in the ground and our instrument cannot filter out these and produces errors. The commercial instruments also have this problem.
9 We also have another problem. In some areas, there are natural currents produced by flowing water. These also produce interference; here they may actually give information we want. But we do not know how to measure and interpret. We can produce the effect by actually putting the instrument near flowing water, even water flowing through a steel pipe.
10 We want to be able to make inverters for operating PC colour monitors on a car battery. We could make it for a TV but not for any higher wattage. We have used simple battery supply with 7805 IC for operating 286 PC with car battery. But with colour monitors this fails. Sealed batteries have to have a low charging rate. And where the power-off time is high they do not get fully charged in the given time.
11 Many diesel engines are not working properly because they are set by intuition only. A lot of fuel is wasted this way. We thought of a diagnostic instrument. But could not make it 5 years back, because the experts said the computer clocks are not that fast. May be they are now, or will be.
The power stroke of a diesel engine produces acceleration in the rotation of the flywheel. This energy is then used for the compression and exhaust strokes. Theoretically measuring the acceleration of the flywheel and the slowing down in the compression and exhaust stroke could diagnose almost all the ills of the engine, beside measuring power out put etc.
Normal engines have a RPM of 1500 to1800. If we attach a fluorescent colour marker on the flywheel and sense it with an electronic device, this could be analyzed time taken per revolution and detect all the health status of all the engine functions. Our friends did not consider this measurement of nano seconds feasible, but if it is now, it will be a very useful device everywhere.
12 Sensors: Among the sensors, we are now doing fertilizer analysis of soil for Nitrogen (Nitrate and Ammoniacal.) Phosphate and Potassium. These are fairly easy. But testing for trace elements, like, Copper, Manganese, Magnesium, Boron etc is more difficult. And trace element deficiencies are more often needed that the standard NPK analysis. Can we have sensors for testing for these elements in soil extracts?