Recent content by mvadu

  1. M

    DS1621 pc thermometer

    Hi Siddharth, Also please mention from where you get LM-2936, because I could not get it here in Bangalore
  2. M

    increasing backup time of ups

    Hi Arun, In my house i have two sections of wiring, one runs all high power appliances like pump, refrigerator. Other line powers all low power devices like TV, FAN etc. I have connected my UPS to the second line. And I have told my mom to "NOT to use all of the appliances together" :) so we...
  3. M

    increasing backup time of ups

    Yes, it does, as i mentioned in my post, my UPS is giving me a uninterrupted supply to my whole house for 3-4 hours. :) About transformer, you need to chanrge the external battery somehow right?, and your inbuilt charger can't carry it off, so you need to have separate charger. Instead of...
  4. M

    Please help on "Telephone voltage levels".

    In India also same DTMF signals are used. You can use a DTMF decoder IC to get BCD equivalent to the key pressed by the caller. When phone line is not used its voltage will be 50V DC, when it rings 50V AC will be applied by your exchange, when you pick up the phone its arround 12-16V across...
  5. M

    Suggesion for LCD (Graphical or Charecter)

    Ya.. even LED is also fine, but the reason why I switched to LCD is other than displaying speed in big fonts, i planed to show up odometer readings also in say 1minute intervals in small fonts. And using cellphone display is not possible because I need a font height of 1 inch, and 4-5 such...
  6. M

    increasing backup time of ups

    Hi, I have done the similar mod some three years back. What I have done is 1. I removed inbuilt battery, 7AH 12V sealed Lead Acid, in that place I installed a 5A 0-18V transformer and a battery change control circuit. 2. I installed a standard 120AH tubular battery outside ups. 3. Connected it...
  7. M

    Suggesion for LCD (Graphical or Charecter)

    Hi I am working on a digital Speedo project. I need to display speed reading in 3:1 digits (three digits and one decimal). Digits should be big enough to read from distance..(as Honda Civic has in its dashboard) I am thinking about using PIC16F628A for communication. But I am not sure about...
  8. M

    Dead accurate 1Hz clock signal???

    The simple most circuit for this would be to take the circuit chip out of a dead watch or a table clock. They use a crystal oscillator and dividing technique. You need to cut off the coil winding and add two diodes (IN4148) on both the outputs (P side of it) and join the N-side to get study 1-Hz...
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