Using the circuit described in a previous blog post:
Switch the wire on post 1 that connects to the port D2 on the Arduino from the switch to the working Hall Effect device Pin 3. Now run the previously built software, when the LED lights up you should see this in the Visual Micro screen (make sure that the baud rate is 9600, that always gets me! Hence the phrase “Work darn it>>”):
It’s ones when there is no magnet and zero when the little LED lights up when the magnet is placed close to the Hall Effect Transistor.
Now lets think about how this could be used: Testing Train Axles for damage while in use, store information on the cloud. Ok that’s it for me, got a reason to put this data on the cloud, Train safety. Good enough, trains are expensive to fix if you wait till something breaks, especially if they derail. Also, it makes for good movies like: The Greatest Show On Earth, the breakout film for Charlton Huston, there is a train crash in it, and if they had Hall Effect Transistors I don’t think it would have happened. Ok, it’s a movie. Other Train crash films though, Burt Lancaster was in one as well…The Train, but it was during WW2 and I think that those trains would have been destroyed no matter what, and the trains destroyed were REAL FREAKING trains. Also, it is rumored that Burt broke his arm during filming and insisted that the show goes on with his broken arm being written into the script. But I digress…
The corporations that own train engines and railway cars use sensors that use Hall Effect Transistors, videos and other tools to examine the rolling stock while in use, storing a Terabyte of data to the cloud during some very short period of time. This is saving the train corporations lots of money or they wouldn’t do it. Find out more at: http://www.ariestesting.com/solutions-by-markets/railway/ . Look there is serious work, not just games.
Give it a try, you should get a Hall Effect Transistor with the Schmitt Circuitry and get it working. This is an important sensor to have in your bag of tricks (toolbox, etc.).
When you have the Hall Effect Transistor AND the Keyes switch working, don’t break down your lab, as you can see the switch allowed to have a known software to test the new sensor. This is another application of the sensors, you may be working for a company that tests sensors for use in their products and you are task with creating a test bed for those devices. In my callow youth I used to use PDP-8 and PDP-11’s to do the same thing. Paid for my way through college! (Well that and the GI Bill for Vietnam Era Veterans, along with a lifeguard job at the Beach, etc.)
If trains run on time and at correct speed then possiblity of accidents is reduced much more(Most of the accidents happen because driver is in hurry or did not notice the signal to stop) than by sticking hall effect transistor in the axel. Also how are you going to download data. you have to build another system for that. most of the derailment happen because of sabotage. It is cheaper to make trains run on time and correct speed with less complexity than build and use this system.
You make a good point about the immediate safety of the train, mine was about maintenance. In the US our trains are mainly freight so the loads are much easier to determine, so it is expensive to have systems run to breaking down on the rail line. So there a number of companies that put in place these kinds of sensors, along with videos, etc. and gather a terabyte of information, analyze it and then throw it away. Pretty cool.