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  1. Externet

    Proximity sensor for parking

    A thin piece of flexible plastic/rubber protruding 3? inches from the trouble point, anchored to a microswitch could work. When dragged/bent clicks the microswitch to sound a buzzer. In other words, a microswitch by the door frame with a long enough-non-marring arm. Wrong orientation for its...
  2. Externet

    Will 13v led lamps run on 12v?

    The picture shows output being from 8.6V to 13V with 23V as max. Seems like a constant current supply for a couple of series leds to several in series, maintaining a fixed 0.7A current. Applying 12V regulated voltage not recommended. Seems the lamps have 4 led in series inside. with no...
  3. Externet

    Help about fridge protector delay time

    Hi ! Perhaps may give some clues: ---->...
  4. Externet

    Any expert in radio-controlling drones ?

    The receiver is the one that has to work at 3V from a solar charged 18650 during the day, enabled to be activated after dusk to turn on a beacon on command.
  5. Externet

    Frequency response ?

    CD writers use laser, not LEDs.
  6. Externet

    Frequency response ?

    Thanks, fellows. Canibalized a Toslink Tx jack from my junk box to use that LED, supposed to be faster. Will see...
  7. Externet

    Frequency response ?

    Perhaps am misunderstood. Up to what frequency can be pulsed ? Trise+Tradiative+Tdecrease+Toff
  8. Externet

    Frequency response ?

    Hi. For plain indicator LEDs, nothing fancy, rarely published in specs... What could be the typical maximum frequency response ? Do they go beyond 10MHz ? Varies with color/chemistry ?
  9. Externet

    Receiving a radio signal...

    Thanks, gentlemen. Dave : I meant knowing if 10.7MHz is present. No audio detection desired. To work on silent unmodulated signals. My searches found complete receivers as your suggested chips. Intention is to know if a carrier is present, on a receiver chip that does not have tuning...
  10. Externet

    Receiving a radio signal...

    Hi. When a radio receiver is tuned to say, 100 MHz; its local oscillator is at say 110.7MHz, the mixer stage produces a 10.7MHz intermediate frequency for later demodulation. If the broadcast ceases to emit, goes off the air; Or, shifting tuning to a blank unoccupied frequency; Or, shorting...
  11. Externet

    Lithium ion polymer battery: What is the 3rd (yellow) lead? what can I use for a replacement?

    If a single 4V cell, the extra wire should be temperature sensing for external management; if a two-series 8V battery, can be a center feed point for external management circuitry if has no protection/balancing board built-in. If a management board is built-in, can also be a 'enable' control...
  12. Externet

    Anyone has schematic of ANY printer with USB port ?

    Thanks. Missed that on the linked page. Previously I looked at another information page about the gadget. Found two more brands for the same application, also belly up, unobtanium. I believed a plain wifi dongle fed with 5V at the printer port should do the bridging...
  13. Externet

    Anyone has schematic of ANY printer with USB port ?

    Thanks, Harald. You are confirming what I thought. But this gadget makes me scratch my head : ----> http://www.actisys.com/Documents/Spec_BT5900US.pdf I asked the manufacturer; hope will get a reply on how is it powered...
  14. Externet

    Anyone has schematic of ANY printer with USB port ?

    Hi. If you have a schematic of ANY printer with USB port; can you please check if 5V is provided at its jack ?
  15. Externet

    Magnet pole pieces...

    Not exactly electronics; please delete if improper. A magnet exhibits its field as demonstrated with iron filings aligned between its poles. Say you have an ordinary bar magnet 1cm x 1cm square, 10cm long Such magnet (N,S at left) fitted with long, straight, parallel pole pieces (upper ====...
  16. Externet

    Any expert in radio-controlling drones ?

    Or, ---->...
  17. Externet

    Any expert in radio-controlling drones ?

    --------------------------------------------------------------------------------------------- Could this be modified/managed as remote control ?? ---->...
  18. Externet

    Any expert in radio-controlling drones ?

    Thanks. Drones are not my toys. Just looking for its components (boards) to implement a remote control using their guts. No intention to fly. Just turn on/off something a mile away that will be powered with 3V.
  19. Externet

    Any expert in radio-controlling drones ?

    Thanks ! Meant transmitter as the handheld control, not any return from the flying unit. OK, good to know - 0.1W at 2.4GHz will reach the mile. Is the flying receiver working on 3V ? - Or any on the market that does ? And something else as it is not my kind of toy... If I buy a 4 channel...
  20. Externet

    Any expert in radio-controlling drones ?

    Hi. Is there 2.4GHz drone receivers that work on 3V supply ? What about less than that, like 2.5V ? Looking for a mile range; what transmitter power is reliable on line-of sight ? 0.5W ? 0.2W ?
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