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  • I'd guess ACs of electric cars are driven by an extra electric motor anyway as they lack that serpentine belt that drives generator, water pump, AC etc. in a combustion car.

    According to Wikipedia, AC consumes about 3KW (or 4HP). That means it draws 3000W/12V=250A. A starter battery has about 36Ah - so it will last 36Ah/250A= 0,144h or about 9 minutes. Bring a lot of extra batteries...

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  • If your lapp is old enough to have a 25 pin printer port (LPT) you can find 5V and GND there. A DVI video output has 5V and GND too.But why not use the USB? Not as a power source, but using the 5V as your power on signal? If you tap into an extension cable, you still can use the port.

    If your lapp is old enough to have a 25 pin printer port (LPT) you can find 5V and GND there. A DVI video output has 5V and GND too.But why not use the USB? Not as a power source, but using the 5V as your power on signal? If you tap into an extension cable, you still can use the port.Or did I missunderstand and you want to switch the laptop on/off via an external signal? In that case ... no idea. AFAIK, there is no such input. You may open the laptop and tap into the power button. Best to use a relay in that case or do some careful measurements not to fry your laptop. Other than this, you may use Wake-On-Lan.

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  • Turn 9V Battery to 5V Battery (simplest and cheapest way)

    No.(Well, maybe just in an emergency, for some short calls.)Take a phone battery - a common one like the iPhone 5s has a capacity of 1560mAh.Even a (very expensive - like 10US$ apiece) lithium 9V battery has only 1000mAh (the fact that it has 9V instead of just 5V doesn't matter, those 4 volts get converted to heat by the regukator...) an alkaline battery is more like 500mAh and a zinc-carbon like 250 mAh...And don't forget that the regulator has no heat sink at all. Remember those 4V voltage difference? Multiply the current needed (and a charging smart phone may want like 2A) with thos 4V to get the power this teeny tiny regulator has to convert to heat. Any more than 200mW (or 50mA) - I'm just guessing here as the data sheet says nothing about the IC in mid air - will probably fry the...see more »No.(Well, maybe just in an emergency, for some short calls.)Take a phone battery - a common one like the iPhone 5s has a capacity of 1560mAh.Even a (very expensive - like 10US$ apiece) lithium 9V battery has only 1000mAh (the fact that it has 9V instead of just 5V doesn't matter, those 4 volts get converted to heat by the regukator...) an alkaline battery is more like 500mAh and a zinc-carbon like 250 mAh...And don't forget that the regulator has no heat sink at all. Remember those 4V voltage difference? Multiply the current needed (and a charging smart phone may want like 2A) with thos 4V to get the power this teeny tiny regulator has to convert to heat. Any more than 200mW (or 50mA) - I'm just guessing here as the data sheet says nothing about the IC in mid air - will probably fry the chip.This circuit may be okay for small loads - a few 10s mA - but keep in mids that the data sheet states a minimal load of 10mA for a stable regulation...

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  • verence commented on Dashing Rainbow Dash's forum topic Encryption and Ransomware?3 months ago

    That depends: If the hard drive is mounted (i.e. accessible, because you started the decryption program and entered the password) the ransomware will encrypt file by file with its own secret key. You can't access the files any more.If the hard drive is not mounted, but just a single gigantic file, the ransomware will just encrypt this big container file. You will not be able to access a single file in it any more.If the hard drive is not mounted and hidden from the file system (like been stored in an 'unused' part of the real drive, well then you are secure. Up to the moment, you mount the drive...

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  • verence commented on 7q2's instructable How to Tie Your Shoelaces3 months ago
    How to Tie Your Shoelaces

    Or do it like this guy.

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  • verence commented on Hafsah Aamer's instructable The Diameter Puzzle3 months ago
    The Diameter Puzzle

    Why so difficult? Fold the circle in half - done. Doesn't even need a pencil ;-)

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  • How to Find Smallest and Largest Number in Array

    What are your tmp variables for? The are not used anyhow.Start your loop with the second element. The first one is already in small and large.for (int i = 1; i < arr.Length; i++)Why a second loop through all of the array to count the appearances of the smallest value? Do it in the first loop.if (small > arr[i]) { indexAmountSmallestNumber = 1; small = arr[i];}else if (small == arr[i] indexAmountSmallestNumber++;In that case, you'll have to initialize the indexAmountSmallestNumber to 1.Getting arr[i] four or more times can be costly. Get it once into a temporary variable and use that, or use a foreach loop.Remove your comments. They are less than helpful. For example://large == 4, arr[i] == 5Well, maybe the one time you checked it in the debugger. But will that help you to unde...see more »What are your tmp variables for? The are not used anyhow.Start your loop with the second element. The first one is already in small and large.for (int i = 1; i < arr.Length; i++)Why a second loop through all of the array to count the appearances of the smallest value? Do it in the first loop.if (small > arr[i]) { indexAmountSmallestNumber = 1; small = arr[i];}else if (small == arr[i] indexAmountSmallestNumber++;In that case, you'll have to initialize the indexAmountSmallestNumber to 1.Getting arr[i] four or more times can be costly. Get it once into a temporary variable and use that, or use a foreach loop.Remove your comments. They are less than helpful. For example://large == 4, arr[i] == 5Well, maybe the one time you checked it in the debugger. But will that help you to understand the code in two years? Good comments do not say, what the code does - good readable code does this itself. Good comments tell you why it does it this way.

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  • verence commented on MarkRadler's forum topic FEATURE REQUEST: Language Selection5 months ago

    +1Especially for your RSS feed - just make one feed for every language.

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  • verence commented on vivering's forum topic Arduino moist sensor with email function5 months ago

    So what's your problem? Finding the sensors? Attaching them to the Arduino? Calibrating the sensor data? Sending an email? Or should we just do all of your school project for you?To get you started:- buy an Arduino, learn how to program it - get a sensor, learn how to attach it to the Arduino, make measurements in wet and dry soil- get a LAN or WLAN module for Arduino and learn how to connect to your local LAN/WLAN - in case you don't have a local internet connection, buy a modem that connects to the mobile phone network and get a SIM card with a data plan- find out, how to send emails- get a LCD and learn how to connect it with the Arduino- get all the parts together and you are done.

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  • verence commented on maalikm911's forum topic Trimmer Engine Generator5 months ago

    1. Would such a combination workIn theory: Yes, why not? In real life: Yes, maybe. 2. Would it be best if I directly connected the engine to the alternator with no drive belts or chainsYes. Any kind of gear system / belts will waste some energy. Unless they are needed to match the optimal speeds of engine and generator. 3. What is the best way to connect the two? As direct and as short as possible. Or, if you need gears / belt discs - as few as possible.4. Where should I remove the engine from the "trimming part". As close to the engine as possible - or as close as you can manage with the knowledge and tools you have access to - you didn't tell us about that.

    A gear system will not change the energy. You can only get higher RPM - with lower torque, or a higher torque - with lower RPM. The power is always the same (minus the losses in the gears). But your generator may have a sweet spot (frequency), where it converts more of that mechanical energy to electrical energy. Same, your engine may have a sweet spot where it runs most efficiently. If those RPMs are too far apart, a gear system is a good idea. You can never get more energy out than you put into the system (in form of fuel), but you can minimize the losses in each step.

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  • Well, no problem. Design the weight pad in your favourite MEMS (Micro Electro Mechanical system) CAD system - just put into mode for silicon (unless you have a multi material foundry) design some micro controller and RF components in your favourite VHDL designer (or buy some ready made IP design), send it al to the foundry of your trust and your done. Should be possible to do it the size of a piece of rice (the RF antenna is the limiting factor).Oh! You didn't want it that small! (How should we know?)Oh! You don't want to design your own µC?! (How should we have known?)Oh! MEMS design is not your strong part ... (How ...)Hey JCDA, What do you really want to do? What have you already done? Where is your problem? What is your level of knowledge? What is the weight? Micrograms? Gram...see more »Well, no problem. Design the weight pad in your favourite MEMS (Micro Electro Mechanical system) CAD system - just put into mode for silicon (unless you have a multi material foundry) design some micro controller and RF components in your favourite VHDL designer (or buy some ready made IP design), send it al to the foundry of your trust and your done. Should be possible to do it the size of a piece of rice (the RF antenna is the limiting factor).Oh! You didn't want it that small! (How should we know?)Oh! You don't want to design your own µC?! (How should we have known?)Oh! MEMS design is not your strong part ... (How ...)Hey JCDA, What do you really want to do? What have you already done? Where is your problem? What is your level of knowledge? What is the weight? Micrograms? Grams? Kilograms? Tons?What is fairly small? Injectable with a syringe into the blood stream? Small enaough to be driven around in a car? .. a lorry?

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