Search results

Search Forums New Posts
  1. Externet

    Pocket Note-Taking Device

    Typing would not be 'like' pencil/paper. Typing would be easier; and for sure applications exist for smart phones. Check ----> https://duckduckgo.com/?q=handwriting+notes+on+phone+application&t=canonical&ia=images for handwriting.
  2. Externet

    Question about a dc motor

    You need a timer integrated circuit set to that 1:3 duty cycle and 20 seconds time on square wave and a transistor or relay driven by it to energize the motor.
  3. Externet

    What the Beeeep...

    Visit an electronics store, service center or amateur radio operator for obtaining that solder at your location.
  4. Externet

    Underwater Wireless Communication

    10 feet underwater, no.
  5. Externet

    AC/DC converter - If I cut/ splice the wire can I use it in my car?

    Leave several inches of the original cable next to the supply and cut only the black wire, not the white dashed one. Remove insulation on both ends of the cut black wire. Plug the supply to mains wall outlet. Connect any automotive spare 12v light bulb between the black wire coming out of the...
  6. Externet

    Underwater Wireless Communication

    From the buoy to the laptop, the Wifi should have no problems. From the submerged sensor to the buoy, Wifi will not work, and if it does, will be because of a very short propagation path but not a reliable way to do it. I would use modulated LED light emission from the sensor to send the data...
  7. Externet

    Ultra-Capacitor Powered Car

    I would not use any buck/boost converter. The current does not need to be limited for one of those kids car. Actually, only two capacitors in series instead of three is more than enough if such toy car works at 6 V instead of your projected ~9 Volts. And it will run for a looong time...
  8. Externet

    Ultra-Capacitor Powered Car

    About 1000F at about 9V ---> Q = 9000 Coulombs. To make the 50 metres in say 60 seconds; the current drawn by the motor should not exceed I= Q/t -----> I = 9000/60 ----> I = 150 Amperes Which seems very achievable. At much less current, one of these should run a loooong distance : ---->...
  9. Externet

    Hacking a microwave oven

    Unsure to believe that only works with presets. There is a numeric keypad to enter cook time. Download the manual and confirm. From what I read, does what you believe does not. Any other model that may only work in cooking combination, could be hacked by just turning off the heating element...
  10. Externet

    Hacking a microwave oven

    Microwave oven plus convection, plus grill in one box ? ----> http://www.bedbathandbeyond.com/store/product/cuisinart-reg-convection-microwave-oven-with-grill/1016719927 ----> http://www.cuisinart.com/products/microwaves/cmw-200.html ---->...
  11. Externet

    Homebuilt Signal Generator

    Do not know and do not care much. I can try to go to the postal office and mail you an envelope with the chip. Am not selling anything anyway, and for hobby purpose. And if trouble happens, they will put me in ¿ jail ?. The world press will have a noisy ball with it. Or do I have to mail...
  12. Externet

    Homebuilt Signal Generator

    Hi tocayo. Find this chip; and you will be very pleased. Performed like a charm in a project done 10 years ago. ----> http://www.intersil.com/en/products/other-analog/special-analog/other-miscellaneous/ICL8038.html?pn=ICL8038 Do not have any of those now; but can mail a XR2206 still in my...
  13. Externet

    Help need for amp. hum

    Power your circuit with a car battery. If there is no hum, the power supply you made is under-rated or bad. If there is hum, shortcircuit the input signal to ground and crank volume up. If no hum then; your input is noisy. If hum then, there is a poor ground in the signal path.
  14. Externet

    Help with transistor radio.

    Check the battery contacts, on/off switch to start. Or find a friendly true amateur radio operator in your neighborhood to attempt the repair. I do not think radio-repairers exist any more. Someone here can bite...
  15. Externet

    Connector advice required.

    Seems it is not a PC fan, but a big MC (mainframe computer) fan. Get a IEC extension cord, cut it in half and use the ends for the source and the fan. ----> http://www.microton.co.uk/image/cache/data/products/cables/power extension 2m-500x500.jpg (small small means nothing) give dimensions !
  16. Externet

    Help with aerial for channel 38

    Just in case, worth mentioning... If the antenna you built is now marginal or not working, will let you know the one I built has that behavior now. Trying to find why, I can only think both, yours and mine where put to work and were satisfactory in winter. Colder temperatures should have some...
  17. Externet

    Help with aerial for channel 38

    Hi tocayo. Two turns should not provide gain in my opinion. Will be detrimental to the frequency of reception. I would place reflectors and director loops in front and back to make it unidirectional gain instead of the current bidirectional behavior. The spacing is supposed to be calculable...
  18. Externet

    Hovering Drone....W/Kg Calculation.....

    Found this, may be of help : Theoretical lift developed by common helicopters: 300 hp, 30' rotor develops 3,400 pounds of lift 25 hp, 12' rotor develops 347 pounds of lift 2 hp, 6' rotor develops 39 pounds of lift
  19. Externet

    Beginners multimeter quest.

    This is one of those surprisingly accurate: ----> http://www.harborfreight.com/7-function-digital-multimeter-69096.html?hftref=cj And often are also coupon-advertised free with any purchase : As of NOW. ----> http://www.retailmenot.com/view/harborfreight.com#print.6960527 Must be original...
  20. Externet

    AC plug for DC purpose?

    Yes. AC plugs/jacks for DC. If you choose a 4 terminal type, can wire two and two paralleled for redundant current sharing. No way to plug it reversed polarity either. And meant to carry the amperage. ----> https://duckduckgo.com/?q=range+plug+and+outlet&t=canonical&ia=images ---->...
Top