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132CommentsVadodara IndiaJoined January 4th, 2007
Am a retired mechanical. electrical engineer.

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  • How to Clean a Coffee Maker With Citric Acid

    I have read in Kodak's publication of photo processing equipment. Citric acid is recommended for removing rust from stainless steel. Another thing it is very good for is removing blood stains from clothes. This I can vouch from my school days adventurers. BTW citric acid is also used in your artificial lemon juice. Like in Lipton's ice tea with lemon.

    Do you add it to salt to prepare the back flushing saline solution to recharge the ion exchange resins? I have a softener that I use for my washing machine and dish washing. It could certainly use a boost !

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  • pmshah commented on JON-A-TRON's instructable Easy Exploded 3D Drawings1 year ago
    Easy Exploded 3D Drawings

    I am a mechanical engineer and the first time I saw these drawings was in parts catalog of International Harvester trucks back in early 60s. We were sole distributors for India. Getting every component in order and in the right proportion such that it also served as assembly drawing fascinated me from my early college days. In these situation use of computers is fine and even recommended but with respect to photography the "art" is lost.

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  • pmshah commented on JON-A-TRON's instructable Easy Exploded 3D Drawings1 year ago
    Easy Exploded 3D Drawings

    When I was studying engineering some 50 years ago making exploded view drawing was a big thing. It was time consuming but paid pretty well.

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  • pmshah commented on audreyobscura's instructable Patch Denim With Fabric Glue1 year ago
    Patch Denim With Fabric Glue

    Just one question. Does the repaired area turn still like the ironed on patches?

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  • pmshah commented on Naran's instructable Cheapest Smart Home for $381 year ago
    Cheapest Smart Home for $38

    I looked for these by googling. All I could find were the US type on eBay and Amazon. I need these for use in India. where I absolutely must have the Schuko type plug and socket. These are theones shown on your instructable.

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  • pmshah commented on Naran's instructable Cheapest Smart Home for $381 year ago
    Cheapest Smart Home for $38

    What is your source for RF Sockets? Any place like AliExpress or DX.COM? Would appreciate a prompt answer. Require them to handle 220 / 240 VAC as just like the ones shown in the images.

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  • pmshah commented on raikut's instructable USB to PS/2 convertor2 years ago
    USB to PS/2 convertor

    Actually for reversing you have ready made adapters available. These have 1 USB plug that will plug into the port on the PC and have 2 pigtails to accepy PS2 mouse and keyboard. Look up on dx.com or aliexpres. These are quite cheap and work VERY well.

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  • pmshah commented on vina1991's instructable 220V HOMEMADE PORTABLE POWER INVERTER2 years ago
    220V HOMEMADE PORTABLE POWER INVERTER

    I think you mean 10 W and not 10 A. 10 A would mean at least 2400 Watts at 240 Volt supply. O beleive even CFLs have a tiny inductor to initiate the lamp by an ionizing high voltage pulse. Perhaps you could try it and give us your feedback. Should not be a problem though. The load might be just too low for the circuit to operate reliably.

    You are sadly mistaken. Refer back to your text books. If you connect the .33 µf and 1.0 µf in parallel you simply get 1.33 µf and not 0.24812 uF as you have said. Here is a link for you that explains properly. http://www.allaboutcircuits.com/textbook/direct-current/chpt-13/series-and-parallel-capacitors/

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  • pmshah commented on vina1991's instructable 220V HOMEMADE PORTABLE POWER INVERTER2 years ago
    220V HOMEMADE PORTABLE POWER INVERTER

    You can simply place capacitors in parallel to add up to the required value. 100 ohm 5 watt can comfortably be used in place of the 1 wall resistor. No problem except for size. In fact it would be better choice from safety point of view.

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  • pmshah commented on noahw's instructable 5 Ways to Clean a Funky Water Bottle2 years ago
    5 Ways to Clean a Funky Water Bottle

    Just for you information, you can get both types of SS. Magnetic as well as non magnetic. And SS does not necessarily mean "rust proof". Unless they are cleaned on a regular basis ALL SS will rust to some degree.

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  • Make a Super PaperJet and fly over a 5-story building

    Nothing new here. I remember doing this very exact thing in my college days, some 55 years ago.

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  • pmshah commented on pizzidave's instructable Coiling a USB power cord2 years ago
    Coiling a USB power cord

    I lived in US for 6 years and brought a whole lot of used equipment back with me when I returned to India. At that time ALL the ac adapters were transformer based and there was no such thing as SMPS designed for international use. and believe me they did run hot and not warm. Blenders mixers and electric irons, almost purely resistive loads were an exception as they were universal type AC/DC operable. The advice of the GE engineers - specific to their A/C unit - worked perfectly and I used my 6 year old - from US use - for 10 more years when finally the plastic body simply fell apart. So don't discount everything out of hand. "THE inductance is a joke at 60 hz" may be true for the specific situation relating to the application here but certainly not in all situations. BTW US ...

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    I lived in US for 6 years and brought a whole lot of used equipment back with me when I returned to India. At that time ALL the ac adapters were transformer based and there was no such thing as SMPS designed for international use. and believe me they did run hot and not warm. Blenders mixers and electric irons, almost purely resistive loads were an exception as they were universal type AC/DC operable. The advice of the GE engineers - specific to their A/C unit - worked perfectly and I used my 6 year old - from US use - for 10 more years when finally the plastic body simply fell apart. So don't discount everything out of hand. "THE inductance is a joke at 60 hz" may be true for the specific situation relating to the application here but certainly not in all situations. BTW US made high speed, high volume photo processing machines that I dealt with for many years used motors which were specifically designed for 50 Hz.

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  • Building The Flat-Pack Bandsaw (AKA the Jigsaw Table) | DIY Woodworking Tools #6

    I see a huge advantage of using this setup. The jigsaw is stationery and you have both your hands free to maneuver your work piece as well as use you foot for power control, preferably by a properly rated momentary switch. Since all of the mains powered power tools are universal type if you rig up a sufficiently capable phase control switch in your foot switch you also have speed control.

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  • pmshah commented on lanleo's instructable Expanding Coffee Table2 years ago
    Expanding Coffee Table

    One way I have found to get clean cut on plywood is to apply masking tape on both sides of the cutting line. This helps in preventing the edges from chipping.

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  • pmshah commented on brian_HobbyCNC's instructable DIY CNC Router2 years ago
    DIY CNC Router

    MDF stands for medium density fiberboard. We also have HDF which is high Density Fiberboard. These are phenol resin pressed extremely dense, heavy, structurally strong, practically impossible to distort. Impervious to water. Can't even nail or screw it without first drilling it and tapping it. Don't even think about using a conventional saw to cut it.

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  • pmshah commented on Ardumotive_com's instructable Arduino Based Smart Home IOT System2 years ago
    Arduino Based Smart Home IOT System

    There are similar ready made devices available on line ranging in price from about € 60 to € 100 for 4 to 12 outputs. Energenie EG-PMS2-LAN by Gembird in Netherlands is one example.The problems I have had with these devices is the fact that the control button on the interface is a toggle and not very useful for automation through application like Aut\oi-It. What I would like to suggest though is a small change in the web interface. Why not provide 2 distinctly separated buttons for each output so that you have very precise unattended control of the output regardless of its previous state. That would go a long way to automate the whole process through Auto-It. What would be really nice would be to have an application running on Windows platform that can control the output fro...

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    There are similar ready made devices available on line ranging in price from about € 60 to € 100 for 4 to 12 outputs. Energenie EG-PMS2-LAN by Gembird in Netherlands is one example.The problems I have had with these devices is the fact that the control button on the interface is a toggle and not very useful for automation through application like Aut\oi-It. What I would like to suggest though is a small change in the web interface. Why not provide 2 distinctly separated buttons for each output so that you have very precise unattended control of the output regardless of its previous state. That would go a long way to automate the whole process through Auto-It. What would be really nice would be to have an application running on Windows platform that can control the output from command line.

    I am fine with browser interface. No problem there. Only suggestion is to have separate buttons for switching ON and OFF. With Autoit script I can open a browser window with specified URL, resize the window, move the mouse to exact location on the screen and left click the mouse. I can run this script from a command line. Essentially I could very precisely switch any output on or off regardless of its status, automatically. Toggle would simply change the state which may or may not be what one wants.

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  • pmshah commented on lonesoulsurfer's instructable Cassette Tape MP3 Player2 years ago
    Cassette Tape MP3 Player

    In case anyone might be interested. AliExpress has quite a choice of casette tape players that output in mp3 format that can be directly saved / recorded on device of your choice.

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  • pmshah commented on vina1991's instructable $1 AUTOMATIC WATER LEVEL CONTROLLER2 years ago
    $1 AUTOMATIC WATER LEVEL CONTROLLER

    Before you use use the NC port on the relay be aware that the current capacity in this mode is lower than the NO contact which completes the circuit upon activation of the relay. In quite a few cases cases substantially lower. You are also dependent on the strength of the contact release spring of the relay which is not such a good idea.

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  • pmshah commented on Robin Lewis's instructable How to Make a Concrete Countertop2 years ago
    How to Make a Concrete Countertop

    Concrete counter tops are fine so long as you do not have to deal with hard water. Any cleaner one may use to remove the hard water stains is going to damage the surface.

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  • pmshah commented on vina1991's instructable $1 AUTOMATIC WATER LEVEL CONTROLLER2 years ago
    $1 AUTOMATIC WATER LEVEL CONTROLLER

    This assumes that the water source is always available and will not allow a situation that can run the pump dry. I suggest you add an quad dual input nand gate IC, work out a karnaugh logic map that also takes into account the water levels in the source tank.

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  • pmshah commented on pizzidave's instructable Coiling a USB power cord2 years ago
    Coiling a USB power cord

    "THE inductance is a joke at 60 hz" Really? Just try running a marginally designed 60 Hz inductive load device ( read - most US products) at 50 Hz and measure temperature rise. I had one hour long chat with GE engineers about how to safely use a 60 Hz US model AC in India on 50 Hz supply. It was an eye opener. Even your low power transformer based AC adapters will heat up under these conditions.

    "Besides you have both sides of the cord there which cancel out.". You are right. That is how Bifilar windings work to make non inductive load resistors.

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