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#1
posted to rec.boats.cruising
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Say Larry..
"Roger Long" wrote in news:46b66da5$0$8977
: http://home.maine.rr.com/rlma/MOB.htm "I also found this nifty little light. Press or hold the switch and it strobes. Press it again and it can be used as a steady flashlight. Twelve bucks. The tiny little module (see insert) will weigh almost nothing on the pole and is all ready to be wired to batteries in the bottom and a switch. The light module weights less than the quarter next to it and is bright enough to light up a room." I copied this paragraph from your webpage...... Notice how you have to HOLD the switch CLOSED to get it to go into strobing mode? What happens when the switch gets a little old and holding it down results in a noisy connection is the IC keeps seeing intermittent presses, not a steady-state hold down for X seconds. One little intermittent interruption when your finger moves is enough to reset the timer that's trying to time down into strobe mode. It's a stupid design with such cheap switches. Clip a jumper wire across the reed switch and see if it doesn't start strobing reliably. If so, it's the reed, even though it will read fine on an ohmmeter which cannot see the pulsing probably going on. I bought a whole bunch of these little 3 really bright yellow LED "Emergency Flashers" from a flea market dealer. He wanted $1 each, but sold me the whole box for $10, what was left. I've given all of them away except what I wanted to keep. The button in it is unreliable in this same way. It's a rubber switch pressing on the circuit board pads. Its sequence is a little different than yours. One press gets a "steady on" light, which is an optical illusion because the LEDs are actually switching on and off at a very fast rate, 50% duty cycle, to save batteries. Press it again and the flash rate goes to about 2 per second at full power. Press it again and SOMETIMES the damned things will turn off....SOMETIMES...(c; The correct term for your observation is called "contact bounce" and has plagued data engineers since before ICs were invented. Most ICs that are forced to interface with humans have a timer circuit at each interface point that takes input, then refuses to take more input until the timer has timed out, several milliseconds, to keep the cheap, noisy switch from giving it 500 button pushes with each finger push. It's called a "debouncer", obviously. Your little light's debouncer isn't timed long enough, now that the switch is crap. ICs are way too fast for their own good....(c; Larry -- Democrats are raising taxes on oil companies by $16,000,000,000. Oil companies don't pay taxes, just like every other company. Consumers pay all taxes, corporate and individual. What's the price of a gallon of regular going to go to to pay $16B more? |
#2
posted to rec.boats.cruising
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Say Larry..
Thanks Larry. That makes sense.
I discovered when I put the thing together that just turning power on and off to the circuit board would result in its always going into flash mode so I just cut the wire to the original switch. A chattering reed switch could certainly be doing this though. Brian's observation about reed switches jibes with my other reed switch experience. I installed an AquaLarm raw water sensor in the boat three years ago. All was fine the first season and it did save me once from overheating my exhaust hose and or engine. Last year, however, it began sounding every time I started the engine and not going off until I went below and moved the adjustment back and forth or banged on it. Big pain. It's been better this year but is starting to do it again. This unit has a magnetic reed switch in it. Too bad. The ideas of a switch hermetically sealed from any moisture is conceptually attractive but I'm not sure thay belong on boats in critical applications any more. -- Roger Long |
#3
posted to rec.boats.cruising
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Say Larry..
"Roger Long" wrote in
: Too bad. The ideas of a switch hermetically sealed from any moisture is conceptually attractive but I'm not sure thay belong on boats in critical applications any more. Other than it all being a cheap piece of boat crap, that aside, reed switches have, after being left on (magnetized) for a time, the perpensity to become magnetic, themselves. The reeds are not supposed to be magnetized, but they get that way. Once this happens, they become either always on by their own magnetism, or so sensitive any magnetic field stronger than the background earth magnetism will switch them on, rendering them pretty much useless. The other problem is the glass case. You wouldn't think it could bend, being brittle glass, but it can! It only has to flex a tiny bit to make the reeds touch "on" again. Sometimes the heat on one side of the glass is more than the other and it'll bend them on without breaking them. I've made a fairly good living on reed switches because Hammond Organ used reeds actuated with pieces of refridgerator magnet rubber for pedal switches for years. All this information comes from observing this design defect and replacing reeds soldered into a really flimsy, cheap circuit board wrapped in a curve around wood screwed down with sheet metal screws as cheaply as possible. Hammond would have never used them. Electromusic in Chicago has no scruples to cheapness under the Hammond name. They made them this way. Well, I just had a panic call from a pudgy little Phillipino girl who plays the organ at her church. When they turned the organ off last night, it stayed on and smoke came rolling out from behind the power switch. The power switch has a paper bypass capacitor to keep it from making a pop in the audio amp and I suspect it shorted and all the organ current went through its short causing a little fire. I got an old Hammond to fix at 1 then I'll meet her after work at 6 to have a look... It's gonna be a profitable afternoon! SEND MORE THUNDER STORMS!! Larry -- Democrats are raising taxes on oil companies by $16,000,000,000. Oil companies don't pay taxes, just like every other company. Consumers pay all taxes, corporate and individual. What's the price of a gallon of regular going to go to to pay $16B more? |
#4
posted to rec.boats.cruising
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Say Larry..
So Larry, what would you recommend for this MOB application?
I have one of those plastic mounted magnetic switches used on windows in burglar alarm set ups epoxied into the pole. The magnet is glued into a Velcro strip with a line to the boat. When the MOB pole goes overboard, the magnet stays behind and the light goes on. Perfect - except for reed switches being unreliable. What would be flush, watertight, and reliable? -- Roger Long |
#5
posted to rec.boats.cruising
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Say Larry..
On Mon, 6 Aug 2007 16:55:40 -0400, "Roger Long"
wrote: So Larry, what would you recommend for this MOB application? I have one of those plastic mounted magnetic switches used on windows in burglar alarm set ups epoxied into the pole. The magnet is glued into a Velcro strip with a line to the boat. When the MOB pole goes overboard, the magnet stays behind and the light goes on. Perfect - except for reed switches being unreliable. What would be flush, watertight, and reliable? There is a reed switch - a mercury wetted reed switch - which is less bad than most - though environmentally suspect. Brian W |
#6
posted to rec.boats.cruising
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Say Larry..
"Roger Long" wrote in news:46b78aba$0$30688
: What would be flush, watertight, and reliable? http://www.nitro-pak.com/product_inf...roducts_id=802 &osCsid=810cd61405cfedde7f1534bb270970af Not sure about "flush"....??? I just hate to think someone's life isn't worth more than a strobe from the flea market when this one is only $20. There's one on my Sospenders with the 10 year Lithium D cell. I go all out when I'm drowning....(c; Why not use the same one on the pole? Larry -- |
#7
posted to rec.boats.cruising
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Say Larry..
"Larry" wrote I just hate to think someone's life isn't worth more than a strobe from the flea market when this one is only $20. There's one on my Sospenders with the 10 year Lithium D cell. I go all out when I'm drowning....(c; Why not use the same one on the pole? Actually, it was a brand new bicycle light that I took apart for the pole. Bike lights are subject to a lot of shock and weather and are a pretty critical safety item so I don't think it's being cheap. The real issue was weight. I could have bought a ready made MOB pole, with a light even, but a lifetime of doing stability calculations told me that the ones I saw in stores and catalogues were going to blow pretty much flat in the water in heavy weather. I wanted to get the light high and the center of gravity as low as possible. Now that we have GPS with instant MOB waypoint input, the primary purpose of the light is to enable the person in the water to find the pole. Trying to find a strobe floating at the surface can be hard for a swimmer because half the ocean seems to light up. Every foot of height counts. The super light bicycle components with a large battery pack making up part of the ballast still seems like a good solution. The rest of the ballast is a length of steel pipe filled with lead. This sucker is heavy but should stand up in any wind that the boat can work against to get back to the person in the water. I just need a reliable switch. -- Roger Long |
#8
posted to rec.boats.cruising
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Say Larry..
On Aug 7, 6:49 am, "Roger Long" wrote:
"Larry" wrote I just hate to think someone's life isn't worth more than a strobe from the flea market when this one is only $20. There's one on my Sospenders with the 10 year Lithium D cell. I go all out when I'm drowning....(c; Why not use the same one on the pole? Actually, it was a brand new bicycle light that I took apart for the pole. Bike lights are subject to a lot of shock and weather and are a pretty critical safety item so I don't think it's being cheap. The real issue was weight. I could have bought a ready made MOB pole, with a light even, but a lifetime of doing stability calculations told me that the ones I saw in stores and catalogues were going to blow pretty much flat in the water in heavy weather. I wanted to get the light high and the center of gravity as low as possible. Now that we have GPS with instant MOB waypoint input, the primary purpose of the light is to enable the person in the water to find the pole. Trying to find a strobe floating at the surface can be hard for a swimmer because half the ocean seems to light up. Every foot of height counts. The super light bicycle components with a large battery pack making up part of the ballast still seems like a good solution. The rest of the ballast is a length of steel pipe filled with lead. This sucker is heavy but should stand up in any wind that the boat can work against to get back to the person in the water. I just need a reliable switch. -- Roger Long A mercury switch? Terry K |
#9
posted to rec.boats.cruising
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Say Larry..
On Tue, 7 Aug 2007 05:49:51 -0400, "Roger Long"
wrote: "Larry" wrote I just hate to think someone's life isn't worth more than a strobe from the flea market when this one is only $20. There's one on my Sospenders with the 10 year Lithium D cell. I go all out when I'm drowning....(c; Why not use the same one on the pole? Actually, it was a brand new bicycle light that I took apart for the pole. Bike lights are subject to a lot of shock and weather and are a pretty critical safety item so I don't think it's being cheap. The real issue was weight. I could have bought a ready made MOB pole, with a light even, but a lifetime of doing stability calculations told me that the ones I saw in stores and catalogues were going to blow pretty much flat in the water in heavy weather. I wanted to get the light high and the center of gravity as low as possible. Now that we have GPS with instant MOB waypoint input, the primary purpose of the light is to enable the person in the water to find the pole. Trying to find a strobe floating at the surface can be hard for a swimmer because half the ocean seems to light up. Every foot of height counts. The super light bicycle components with a large battery pack making up part of the ballast still seems like a good solution. The rest of the ballast is a length of steel pipe filled with lead. This sucker is heavy but should stand up in any wind that the boat can work against to get back to the person in the water. I just need a reliable switch. I don't really want to get between Larry and an electrical problem but I did once know a bloke that had a built in tube, in the transom, where he stored his MOB pole. It apparently had a mercury switch built in. If it was horizontal it was off, vertical on. Seemed to work all right. As an aside I believe he had some sort of launching device, i.e., pull the handle and WOOSH the pole was deployed. Bruce in Bangkok (brucepaigeATgmailDOTcom) |
#10
posted to rec.boats.cruising
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Say Larry..
There is no switch more reliable than a mercury wetted switch. There are no
moving parts. The pole should be graphite and all the electrics should be in the bottom, including a 406 MHz EPIRB. Store pole on the rail bottom up. Steve "Roger Long" wrote in message ... "Larry" wrote I just hate to think someone's life isn't worth more than a strobe from the flea market when this one is only $20. There's one on my Sospenders with the 10 year Lithium D cell. I go all out when I'm drowning....(c; Why not use the same one on the pole? Actually, it was a brand new bicycle light that I took apart for the pole. Bike lights are subject to a lot of shock and weather and are a pretty critical safety item so I don't think it's being cheap. The real issue was weight. I could have bought a ready made MOB pole, with a light even, but a lifetime of doing stability calculations told me that the ones I saw in stores and catalogues were going to blow pretty much flat in the water in heavy weather. I wanted to get the light high and the center of gravity as low as possible. Now that we have GPS with instant MOB waypoint input, the primary purpose of the light is to enable the person in the water to find the pole. Trying to find a strobe floating at the surface can be hard for a swimmer because half the ocean seems to light up. Every foot of height counts. The super light bicycle components with a large battery pack making up part of the ballast still seems like a good solution. The rest of the ballast is a length of steel pipe filled with lead. This sucker is heavy but should stand up in any wind that the boat can work against to get back to the person in the water. I just need a reliable switch. -- Roger Long |
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