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bobleny's Achievements


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  1. So, I am working on an alarm system for my bike. As apart of that system, I would absolutely love to have it recognize me from a short distance, say 1 to 2 meters away, and deactivate the alarm and turn the accessories on. For that to work, I would obviously have to keep something on me that could either be read by the bike or something that could send a signal to the bike. My current thought is to use a micro controller to create a public private key pair. It would of course transmit the public key that the device I have on me will use to encrypt a secret password known only to device on me and the bike. How can I do something like this? Can anyone think of a way of doing this with out having to carry around a brick sized device? It would really be nice to just shove something in my wallet. Does anyone have any other ideas on how to something similar? Thanks!
  2. So, I am looking at this project here: http://www.serasidis.gr/circuits/AVR_oscilloscope/avr_oscilloscope.htm I am not actually interested in building an oscilloscope, I am more interested in building a 120-240 vac 50-60 hz signal analyzer. I would like to build something for monitoring the power being fed from the electric company into my house in as close to real time as I can get (obviously it takes time to convert and analyze the signal). The project won't work for what I want it to, but I feel that it is not too far off. My questions are... Can I increase it's voltage range to meet my needs, or do I need to use a transformer to lower my line voltage? --> If I use a transformer, is that going to significantly alter my signal? The probe circuitry uses an amplifier. Would I really need an amplifier in this case? He says he increased the sampling rate from the last project. Is there any way to actually calculate what that rate is? Thanks!
  3. How do I create an inductive switch? I know you can buy them, but I'd like to make one. Does anyone have any one know where I can find a circuit diagram of a simple inductive switch? Thanks!
  4. Well, the fuss is, I don't want to break my electronics!! However, it never occurred to me that they would have a built in voltage regulator. Of course, now that you pointed that out, it seems stupid that they wouldn't. That's why it was so strange to me that there was such a large difference between what the devices input was rated for, and what the wall adapter was pumping out. Now I just feel stupid... Thanks!
  5. Thanks, that answers my question. Now I'm wondering how to get around this problem of 12v in to 12v out. I know they make low dropout regulators, but even if the dropout voltage is .01v, I will still run into the same issue. It doesn't seem wise to use a 20v regulator to power a 12v regulator. Are there any other options?
  6. I was actually referring to a 15V regulator for everything. I don't have an effective means of measuring the voltage under load. I doubt any of them are regulated, but the router, because of its 13.7v, might be. I'll just get a 12v regulator and run the modem, router, and answering machine off of that, and the speakers off of the battery. I did read the datasheet; that is where I learned of the dropout voltage. What I don't under stand is if it is a 12v fixed regulator with a 1.5v dropout, how can it have an input range of 5v to 25v? Does the voltage dropout when you give it a 12v input? I'm guessing the current drops, not the voltage, right? There are two graphs that mention the dropout voltage in the datasheet, which can be found in the link above or here: LT1085CT-12, but the graphs don't mean anything to me. They are comparing the input output differential to the output current, but I'm not really sure how that helps. That is where I got the idea of the max current dropping and not the voltage.
  7. I'd still like to know what happens when you run a 12v regulator on a 12v source. I guess I'll just have to buy one an find out the old fashion way...
  8. That and glow plugs are only used to start the engine. Once the engine is running they turn off. Do all alternators produce the a nice sine wave?
  9. You are correct, they are running at 15.5V. If I where to hook them up to the battery directly though, wouldn't they get quieter and quieter as the battery drained? I was curious, so I checked the power supply's of my modem, router, and answering machine as well. The modem and router are both rated at 12VDC. The modem is 17.2V. The router is 13.7V. The answering machine is rated at 7.5V, but the power supply is supplying 13.2V. What I find most interesting about this is the voltage of my incoming power, which is 112V AC. I know a lot of houses, in America anyways, are running closer to 120V AC. I guess that means most electronics aren't as picky as I thought they where. Still though, my modem is always really hot, maybe I should run it on a lower voltage? Should I just get a 15V regulator and call it a day?
  10. I will do that the very next time I get my hands on an oscilloscope. Sure, but not all diesel engines have glow plugs. This one for example does not. I suppose without seeing an actually picture of the output, it is a little hard to tell exactly what kind of distortion it is producing, huh? I did hook up a Islatrol active tracking filter which is a "high-frequency noise filter with transient protection for critical loads," but it had no real effect. I will work on getting a picture of the output and continue to hold, one hour at a time, as my call is very important... ::)
  11. I'm trying to build a basic power supply for a few of my electronics, which include my desktop speakers. My concern at the moment is the voltage dropout rating. I've never built a 12V regulated power supply that runs off of a 12V battery. I was looking at a LT1085CT-12 from Digi-Key. It has an input range of less than 25V (I guess that means I don't even need a battery) and a dropout voltage of 1.5. This is to run off of a battery that will have a voltage range of about 10.5V to about 14.5V. The maintenance charge is about 13.5V. So, assuming a voltage dropout of 1.5, if I hooked up this regulator, would I get 12V? What happens when I remove the battery maintainer and the voltage drops to about 13V? Do I all of the sudden get no voltage? Is the actual input range 13.5V - 25V and less than 10.5V? Thanks!
  12. Sorry for the delay, I'm still trying to get a hold of the manufacture of my generator to see what they can do, if anything... Well, the graph I made only shows the worst couple of spots. There are spikes and dips along the entire have form. I was just really lazy in drawing the graph. On the good side though, it is very constant. It was almost like looking at a picture on the screen. I don't know what you mean by ignition system. I know I didn't specify before, because I wasn't sure what the output rating is, but it is a 6kW pull start generator. As far as I know there is no ignition system. There is no battery and there are no glow plugs... I'm not familiar with AC capacitors and I can only assume you need special inductors for AC as well. I do remember building a DC power supply a while back in which I used a very specific formula, some capacitors, and some inductors to get my ripple to basically zero. Is there a different formula I need to follow with AC? I don't want to flat line my AC... What kind of capacitors do I need? What kind of capacitance would I need?
  13. I'm not sure if this is the right forum to put this in, I'm not even sure if this is the right site to post this in, but I have a diesel generator that produces 120V AC via a badly regulated alternator. It was actually causing our ACP UPS's to go nuts and click on and off repeatedly. I finally got the chance to hook it up to an oscilloscope and found out why. It looks kind of like a really bad stepped sine wave. Here is a really bad illustration of what it kind of sort of almost looks like: Unfortunately, I didn't have the foresight to take a picture of it. It has the basic shape of a sine wave and the peaks are at about 175V, but all along the line it had several voltage drops similar to the ones illustrated above. I just showed the worst ones, very little of it, if any, is smooth Like I would expect. So, I need to find some way of fixing the power. I would like something that I plug in line between the generator and the switch panel. I did find a power conditioner by APC but I don't think this would do what I would like it do, defiantly not on the scale I would like it to work. http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=h15&tab=features I've read several posts in various forums on this subject and they all seem to say the same thing, you shouldn't have bought such a piece of crap. I was hoping you guys, who seem to be very knowledgeable would be able to provide a better insight. Any ideas? Why is it so are to make dirty AC pretty? Thanks!
  14. I know it's not magic, I was only joking but thank you for the explanation...
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