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  1. K

    Garage door open switch to Honeywell thermostat

    How important is it to keep the garage interior from freezing? As an alternative, you might consider (ONLY IF THERE ARE MULTIPLE FUNCTIONING OBSTRUCTION SAFETY SWITCHES) an automatic, timed door-closer. A reed or microswitch indicates door is opened and starts timer. At the end of the time, the...
  2. K

    Reducing Energy consumption in Data Center

    Since a major portion of your energy consumption is for cooling systems, move your server center to a location with cold climates. Big server centers like Google's are actually doing that. Since cooling with increased temperature differential have increased efficiency, that's 4+ months a year...
  3. K

    Wanted: Jeco/Smith tuning fork movement (working only).

    I would go to the local thrift/second-hand/Goodwill store and buy an old battery wall clock. Remove the cover and hands. Unscrew the 3/8" nut. Pull the movement out. There you go. Ken
  4. K

    Help with a timer circuit

    You might try this. Not bench tested, so I'm not sure of the value for C1. I would probably go with a MOSFET version as you could a smaller cap for C1 and get longer times. Ken
  5. K

    how to make buzzer only beep once.

    A relative simple solution with passive components. The buzzer will beep and the LED will flash momentarily as the magnet passes the reed switch. If the magnet stops with the reed switch closed the buzzer will beep once and the LED will stay on. Ken
  6. K

    A new concept for the electric kettle

    Measuring on the bottom of the container vs the top center will show some variation. But heated water is turbulent and distributes the heat throughout the container. The closer the heat source temperature is the desired water temperature the less variation you will see. I can't see any way that...
  7. K

    A new concept for the electric kettle

    Can you elaborate on that? Ken
  8. K

    A new concept for the electric kettle

    How is a sound detector or a pressure sensor going to be more accurate than a temperature sensor/controller, when water "temperature" is the goal? Ken
  9. K

    speed control system

    Google: cascade control Ken
  10. K

    Transformer

    It helps to let us know where you are when asking for component sources. That one looks like it will be OK. Ken
  11. K

    Transformer

    Where in the world are you? Ken
  12. K

    Transformer

    Fairly inexpensive: http://www.mpja.com/12V-CENTER-TAP-6-0-6-1A-TRANSFORMER/productinfo/7838+TR/ or http://www.mpja.com/12VAC-40VA-Plug-Transformer-Ault/productinfo/18556+PA/ Ken
  13. K

    Digital Door Sensor

    For starters, Google: USB counter Ken
  14. K

    A new concept for the electric kettle

    That sounds sort of Rube Goldberg'ish. Since water temperature is what you're concerned about, why not just monitor/control the water temperature? Or am I missing something. Ken
  15. K

    magnetism.

    Actually, it's the high current discharge through a low resistance path that cause the damage. (Well, it really is a result of the high voltage charge.) If you're holding an IC and scuff across a carpet, the IC is OK....until it gets between you and a low resistance ground return path. If you're...
  16. K

    Re-routing an analogue signal

    OK, those are "line-level" signals...~1v. You can do it with a 2P3T mechanical switch. Or, by an analog-switch IC like a CD4066, controlled by a CD4017 or a CD4022 or a microcontroller. Do you want to press one switch that steps through the 3 inputs with each press? Or, 3 pushbutton switches...
  17. K

    magnetism.

    Are you grounding a metal bench frame and/or a metal bench top? Ken
  18. K

    magnetism.

    "Magnetized" tools will not harm electronic components. Static electricity (from low humidity in winter months) can though. I also don't think speakers will harm electronic components, though they may induce spurious signals in to nearby, sensitive, electronic circuits. Ken
  19. K

    Re-routing an analogue signal

    Still confused :( Again, do you mean: 1. 3 low level inputs--->3xswitch--->1 amplifier--->1speaker? or 2. 3 low level inputs--->3 amplifiers--->3xswitch--->1 speaker? If #1, what is the signal voltage levels of the inputs. If #2, what is the amplifier's output power. Ken
  20. K

    Re-routing an analogue signal

    Almost any microcontroller with 1 input to step through 3 inputs, or 2 digital inputs for three buttons (00,01,10,11)...and 3 digital outputs will work. So, are you switching the outputs of three power amplifiers to one speaker, or three line inputs to one power-amplifier and speaker? Ken
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