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Hero999

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Everything posted by Hero999

  1. If you want to attach a file, please upload it here, rather than over there. Don't worry too much about viruses, audioguru. Opening a zip file is a fairly low risk activity, far safer than installing software or even viewing a Word document. Even if it does contain a virus which isn't detected by your security software, it's unlikely to run unless you tell it to, i.e. you open the zip file and load an .exe file stored within the .zip. I'll do the following myself, when I have the time: Download the .zip Check it really does have a .zip extension and isn't executable i.e. it isn't really files.zip.exe Scan it with antivirus software. Open it with 7-zip. Check that none of the files are executable before extracting the files. Scan the extracted files with anti-virus software, just in case the scannercouldn't read the zip. Following those steps will greatly reduce the risk of viruses. If all is good, I'll attach the file here.
  2. It's probably too late the original poster but hopefully others will still be reading this. You can buy USB controlled power saving plugs. Perhaps you could use an MCU to control one via USB. http://www.savingtrust.dk/public-and-commerce/products/energy-saving-equipment/autopoweroff-plug-banks/autopoweroff-computer
  3. Oh I misread it. What mean I mean is why do you need to store energy? The 12V battery is still there right? All that needs to be done is not switch the light directly. The light could be connected via the control system (microcontroller and transistor/relays) which is permanently connected to the battery. The control system would then be programmed to respond to the switch's status.
  4. Forgive me for butting in, I've not had time to read the entire thread. I notice there are lots of LEDs connected in parallel; why? It's more efficient to connect them as three strings of five or even five of three. If all this does is buffer the PWM signal then why use an op-amp IC? A comparator such as the LM311 or LM393 would be a far better option.
  5. What do you mean by reverse energy? It can be done with a simple microcontroller, which is basically a very simple computer on a single chip, that can be programmed to do a variety of different tasks. There are other ways of doing it with logic gates, transistors and relays but by the time you've done that, you might as well have invested the time and money in learning about microcontrollers.
  6. They're not surface mount LEDs but through hole and the sopts you're talking about are the semiconductor LED dies themselves. How much current do the LEDs draw? You could build a tiny PCB with resistors and SMT LEDs but the trouble is building a nice convenient package for it.
  7. http://www.rapidonline.com/Tools-Equipment/Peak-Atlas-DCA-Semiconductor-component-analyser-36637
  8. I wouldn't recommend tapping into the dryer's electrical system. Although it would be a more complicated project, it's much safer to monitor the sound from the buzzer and trigger a relay.
  9. That circuit is wrong, the transistor is configured as an emitter follower with no gain so there'll be no oscillation. Here's a link to the correct version, with a better explanation: http://users.silenceisdefeat.net/~lgtngstk/Sites/Circuits/Buzzer/Buzzer.html It can be made louder by replacing the collector resistor with an inductor: http://homemadecircuitsandschematics.blogspot.co.uk/2011/12/how-to-make-simple-piezo-buzzer-circuit.html
  10. The motor will look like three inductors, each with a resistor in series, connected in delta.
  11. You haven't been provided with enough information to answer the question: without knowing the line frequency, it's not possible to solve the problem. You need to break the loads down into their inductive, reactive and resistive components: To calculate the resistance of the lighting circuit just use Ohm's law. You can calculate the capacitor's value using Ohm's law to get the reactance and transposing the formula for the impedance. The resistance and inductance of the motor can be found by transposing the power factor formula, to get the resistive and reactive components, then transposing the impedance formula to give the inductance. All of the above requires the line frequency, which is unknown.
  12. No I don't. So what do you want me to do about it? Do you want someone to design one for you? How much are you willing to pay? So far you haven't even given a proper specification, so how do you expect anyone to help you?
  13. It's nothing to do with switching speed, a logic level MOSFET has a low threshold voltage so can be switched from 5V or less, a normal MOSFET usually needs 10V.
  14. But I thought you were talking about DC current? Deriving the DC current is easy: you need to know the resistance and voltage and use Ohm's law. Calculating the AC current is also not difficult but you need to know the inductance too. A Hall effect sensor will work but for AC it'll need to work up to the frequency being measured. But why do it the hard way? It's DC so measure the resistance of the coil, the voltage across it and calculate the current.
  15. http://www.google.co.uk/search?client=opera&rls=en-GB&q=MOSFET+BJT+advantages+disadvantages&sourceid=opera&ie=utf-8&oe=utf-8&channel=suggest Going from your previous posts, you need a logic level MOSFET. You don't need a 12W resistor, as the power dissipation will only 12W for a few ms, a lower power resistor (try 1W or 2W) will be fine as the power won't be applied for long enough to overheat the resistor. With no resistor to limit the current, all of the power will be dissipated in the transistor which will have a lower resistance than 12R so will dissipate much more power, possibly enough to overheat it.
  16. There is no point in using an opto-coupler, if both circuits use the same ground.
  17. Nice project, assuming you really did build it yourself.
  18. Robot spies: sounds interesting. Who are you spying on?
  19. You need to know both the current and voltage,in order to calculate the resistance, for more information look up Ohm's law.
  20. Why didn't you say that before? What's an Rbatm?
  21. That's odd, it was working before, try this: http://buenotech.en.made-in-china.com/product/NewJdEgbyjkq/China-6-Channel-Digital-Fiber-Optic-Video-Transceivers.html
  22. http://www.huihongfiber.com/6-channel-video-optical-transceiver.html
  23. This is the open forum. All my signature means is please ask questions here, not via private message/email.
  24. No because the voltage isn't high enough to cause a large enough current to flow through you to harm you.
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