Search results

Search Forums New Posts
  1. C

    Reviving an LED Lantern

    the lm2596 is a simple switching regulator which set to 7v would chage your battery nicely... ideally you'd need a current adjust circuit to to prevent the battery getting > 1.5a max current surge on a 6v lead acid... but since you want to use lithiums, you'd need to keep a nice steady 6v to...
  2. C

    Reviving an LED Lantern

    wait..no sound? the electrolyte has dried, you might be lucky enough to get inside to top it up... stick with the lithium idea :p
  3. C

    Reviving an LED Lantern

    any 12v charger will do, then use an lm2596 or lm317 to fine tune it (lm317 is cheaper but less powerful so to speak .. up to 500ma from 12v is about the limit with a small heatsink...
  4. C

    Reviving an LED Lantern

    ok, shake the 6v battery... if you hear rattling noises, bin it... if you hear liquid swishing about, then you might be ok, a slow charge of a couple hundred ma over night (as simple as a resistor from 7.5v) first time charge... it's difficult to say without specialist tools, normally you'd...
  5. C

    Reviving an LED Lantern

    you need 7.5v to charge this battery.... chances are you'll have standard 5mm leds to power.. 2 lithiums in series would supply over 8v possibly damaging the circuit, an ldo at 7v might be an option. ..
  6. C

    LED Voltmeter circuit

    Because of the small power requirements of the 555, you might be able to use a 5v zener.. i'm not sure if a 7805/lm317 ... can handle 50v but a zener should if it's purely powering the 555... this job is would be easy if not for that 50v supply...
  7. C

    Personality Translator..

    A few years ago while using yahoo chat, someone developed a tool to give your text/speech a personality, i've been bringing it back to life! basically it's a text tool, disguises your text as a personality, a valley girl or pirate.. next step is to add a facebook share automatically, suggest...
  8. C

    LED Voltmeter circuit

    You also deal with 50vdc the 555 will not cope unless you step down the voltage first...
  9. C

    Resistances of different lamps

    You'd need to switch on the bulb until hot, then quickly before it cools down measure the resistance. .. the resistance will change as it cools
  10. C

    Walky Talky (no internet required!)

    how'd you mean? groups over local area network? because this does not have a server or ip like voip has, it uses multicast over udp... channels (eg channel 1 to 255) and only if you listen on these channels will you hear it? or have i misunderstood?
  11. C

    Piezo-triggered twinkling LEDs

    A small arduino nano clone for $4.. Simply using some silver thread (which basically is the resistor) fabric from each pin.. digitalWrite (pin, HIGH); or use multiplexing to give a twinkle effect... if you go past the max pin out you'll need shift registors and possibly transistors to drive...
  12. C

    cheap mains stepdown 240-120

    if it's a computer power supply, replace it with a 240v supply....
  13. C

    Walky Talky (no internet required!)

    i think i've ironed out all the kinks now (it was lagging when broadcasting) so until now i was hesitant to share it... how it works... it uses your modem/router and broadcasts your voice over udp to any other device running the app, i've had it running ok on 3 androids all in different rooms...
  14. C

    State of Charge LED indicator

    https://www.google.com.au/url?sa=t&source=web&rct=j&url=http://www.ti.com/lit/ds/symlink/lm3914.pdf&ved=0CBsQFjAAahUKEwj5w6Sky9nGAhUhraYKHZT9Cq8&usg=AFQjCNFpAsuQaolL4LLf9GuyFDXAvJoLOw&sig2=rutSm_zfB_GPWDoSZ_AXhw
  15. C

    State of Charge LED indicator

    Datasheets! modern man's best friend lol
  16. C

    State of Charge LED indicator

    ah... just 2 resistors to make a voltage divider, a zener can be added to prevent it going over say 5v (depends on the ic...)
  17. C

    State of Charge LED indicator

    The everycircuit one? that's purely a voltage status, full battery all led's light, low battery only 1 or 2 LED's will light... i cloned the circuit you already had to show you how it worked... i've not given you a chaser circuit...
  18. C

    State of Charge LED indicator

    you could divide the voltage to make it usable with any chip/processor .. eg a voltage divider reducing each step to a max if 5v (possibly with a zenner) feeding all those inputs into a shift register, then read each state of the led... there's many ways, just make sure the input matches the...
  19. C

    Sensing circuit for line following robot

    either your circuit is wrong or the opamp is faulty... are you measuring a voltage across the ir led when it's operational?
  20. C

    State of Charge LED indicator

    the lm3914 is just one ic chip of thousands, it's difficult to find emulators packing all the ic chips! and once you do find one... A. does the chip support 40v+ B. does the chip support sinking/sourcing current capable of driving the LED? (If it does not, more circuitry required) Welcome to...
Top