Real-Time Sensors

I once got in the car I purchased for my kids to use and noticed the speedometer did not register how fast I traveled. While I could see fine outside and had a rough estimate of how fast I was going, I sort of felt blind. I immediately turned around and headed home to see if I could fix the problem. Fortunately I just needed to spray some contact enhancer on the plug going from the car's computer into the dash gauges and everything started working again. While I was never in any danger, I sure felt unsafe on the road.

We have a lot of sensors that provide real-time feedback and tell us exactly what is going on. A speedometer is one very useful example. I used to own 2 boat, one in California and one here in Salt Lake. The one in California didn't have a depth meter while my one here does. I used to sail around the San Francisco Bay and just always assumed I had enough water underneath me to keep me out of trouble. With the shrinking of the Great Salt Lake, my depth finder is a critical piece of equipment. Lately I have been unable to sail because the lake is too shallow. Fortunately my depth finder has kept me from grounding the keel in anything but soft mud.

This morning I had a doctor's appointment where I got a spot check on a number of my health indicators. I stood on a scale and could see that I gained a half pound since my last visit. The nurse took my blood pressure and told me I am incredibly healthy because both numbers came in well under the 120 by 80 that we use as a standard. On Monday I visited the lab where they drew blood and provided many more health indicators. Unfortunately it is impossible to provide real-time values for most of those numbers. When I visited the lab, I had to do so fasting as eating anything has a tendency to skew results. 

I am one of those people that is very health conscious. I don't understand how anyone can smoke cigarettes as they are knowingly shortening his/her life. My visit to the doctor increased my own awareness of how important it is to get constant feedback on how healthy I really am. For someone who is watching his or her weight, standing on the scale provides constant feedback. Naturally it is best to choose the same time every day to measure one's weight as it fluctuates throughout the day depending upon a number of factors including what one is eating or drinking. I wonder though if we constantly measured our weight if it would help us reduce our portion size. You might look at that cheesecake a little differently knowing it might tip the scale against you. Perhaps we should remove the scale from our bathroom and put it in our dining room. Then again, eating is a pleasurable activity and a monitoring device might detract from it.  

How Smart Traffic Lights Work

One of the advantages of taking Electrical Engineering classes in college and having a degree in the subject is that I learned how a number of devices in our society work. The other day I saw someone who sent their children to jump up and down on a sensor used to detect if a car is overhead. In this case they were trying to open an arm for a parking lot but it is the same technology for traffic lights. Unfortunately this adult erroneously believed that traffic sensors are triggered by weight. I thought the same thing growing up. Imagine my surprise when I attended my Electromagnetic Physics class and the professor informed us that it is just a metal detector buried under the asphalt?

Before college I tried like those kids to get my bicycle to trigger traffic lights to turn green for me. After doing a number of bunny-hops with no luck, I would sheepishly walk over and push the pedestrian button. After college I learned a trick and can now trigger traffic signals to turn green for me about 80% of the time. The bike I currently use to commute has an aluminum frame. While aluminum is a great conductor of electricity, it isn't magnetic and that is what a metal detector is looking for. Iron is magnetic and also rather heavy so they try to use as little as possible of it in bicycles. There is one place they can't avoid it though and that is the bike chain. I have discovered that if you ride so your chain is directly over the sensor, there is enough iron in it to trigger the light. This may take a bit of trial and error for some lights but I have learned where all of the sensors are on my 3-mile ride to and from work each day.

When I saw those kids jumping up and down on the car sensor, I politely asked them to move and rode over the sensor. My trick worked and they entered the parking lot without any trouble. It is a simple trick but looks like magic to young kids.