On New Year's Eve, I was cooking fillet steak for a party with some friends. I first put it in the pan to sear it and then in a hot oven for a few minutes to finish it. As I was pulling it out, a beeper in the oven control panel started screeching. As the steaks were done and there was nothing obviously wrong with the oven, I simply turned it off at the fuse box and went on to eat the steak and ring in the New Year. I switched the oven on again prior to going to bed, but about two hours later it started beeping. I crawled out of bed and switched it off.
In the morning light, I switched the oven on again. Sure enough, a couple of hours later, it started beeping and none of the buttons would quiet it. I deduced that if the beep started with a cold oven after a couple of hours then it was unlikely to be an over temperature alarm and was most probably a time out -- i.e., the timer had counted down to zero. I switched it on again to observe pre-beep performance.
This time I noticed that the clock button, which was a plastic sheet over contacts on the faceplate, did not set the clock mode but did activate the timer in the same manner as the timer button. Then I perceived a slight bump in the plastic over the clock button icon. At this point I could deduce that something, possibly to do with the bump, had somehow jammed the clock button and set the timer counting down.
I then removed the front panel of the control unit. The plastic sheet covering the front panel had a transparent area over a slot behind it, which was where the clock display was mounted. And the slot was just over the row of push buttons. Just at the edge, where the plastic covered the slot, I saw the dessicated cadavers of some tiny insects.
I shook those out, inverted the faceplate, banged it on the table, and for good measure, ran a piece of paper between the plastic and the faceplate. Several bits of exoskeleton showered out.
After reassembly, the oven worked perfectly, and I now know what debugging means!
This entry was submitted by Phil Hughes and edited by Lauren Muskett.
Phil Hughes is CEO of Clustered Systems Company Inc.
Tell us your experience in solving a knotty engineering problem. Send stories to Jennifer Campbell for Sherlock Ohms.
My uncle was in the Signal Corps in the Pacific in WWII. He used to tell me about how the rats would try to get into the transmitters to get warm and dry out. Of course the results of a rat getting across a several KV plate supply is somewhat more spectacular than an insect across a low voltage switch.
tekochip, sounds like you did a much more thorough job of designing--and testing--those interfaces than some of the examples we've heard about here. I like your "Twister" description--makes it easy to visualize.
Anytime one of these stories concerns food preparation and bug in the same story it gives me the crrep. I also do not like mebrane covered buttons and much prefer a keyboard type setup.
@Elizabeth: You find it hard to believe that a bug could be the source of the problem. I saw an ant colony bring an M-1 tank to a standstill. It had nothing to do with engineering and I hope the editors see fit to let this story fly.
We were on an operation in the jungles of Vietnam and my Armored Personel Carrier was following behind a tank as it busted brush. It approached a tree with a large cluster of red/orange leaves, that appeared to be dead. When the tank hit the tree, the red/orange fell out of the tree and covered a good portion of the tank. It wasn't leaves at all, but a colony of army ants. The ants quickly began biting any warm body they contacted, which was about 6-8 soldiers in and on the tank. Now if you were dealing with just a few it was no big deal and you could swat them off, but when there were hundreds the pain was unbearable. They quickly got under your clothes and the only thing to do was get out of the area, get out of your clothes and start beating them off.
So here sat the tank while the whole crew bailed out and off the tank pulling off their clothes while swatting ants off each other while jumping and screaming. You would be amazed at how fast those ants and their victoms can move. I saw one guy pull everything off without undoing a button or zipper. After the fuss had settled we poured diesel fuel around on the surface of the tank which seemed to solve most of the problem, but periodically for several hours we heard yelps and saw swats as the tankers discover ants not detered by the diesel fuel.
So when someone tells me a bug can mess up the works, I remember when I saw them stop a machine of war.
When I first got an oven with one of those touchpads, I was happy--thought it was cool. Now, 10 years later, it's failing--you have to push harder and harder to activate the contacts underneath. Sometimes the timer just doesn't work, since that's the function I use at least once a day.
Tool_maker's story made me sit up straight. The possibility of the "bug" in a system being an actual bug is an old joke in electronics. It's a joke because the actual occurrence is more than a pun, and has actually happened, according to my tech support friends back in the day.
On another note, the "beeping" sound of common appliances need to be toned down. I once took apart a microwave and removed the speaker for that reason. A volume control is a must. Also, remove the last beep of the warning cycle is key.
Just Like Father Guido Sarducci said about the birthday song, it's too long. Remove the second "happy birthday to you," and it's tolerable.
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