Search results

Search Forums New Posts
  1. kellys_eye

    Wireless proximity detector that goes off when blocked

    There's a possibility of detecting lack of content using sound - much the same way a car engine management unit can detect knocking, you can detect a change in sound from the lack of material sloshing around the hopper. It would take some experimentation to determine the type of signals...
  2. kellys_eye

    DC to AC converter

    Such low levels of AC could be generated using a simple oscillator and amplifier and give a true sine wave. But if the equipment uses a 12V AC input it's likely to convert to DC inside anyway and the the AC adapter could be changed for a DC adapter at the appropriate voltage (around 15-16V)...
  3. kellys_eye

    Remote shotgun blast sound

    300 yards? Not an easy task. The sound energy in a real shotgun blast is enormous and not easily reproduced electronically without considerable effort and a large, powerful amplifier/speaker arrangement. MP3 is a good idea and the actual sound reproduction would be accurate using it but...
  4. kellys_eye

    Wireless proximity detector that goes off when blocked

    Proximity detectors rely on the physical attributes of the object being detected - the human body is a massive sack of s**t - errr, I mean water which is easily detected (it alters tuned circuits by capacitance) but the likes of cookies (as your example) hold little water or any property that...
  5. kellys_eye

    (1973) Imperial HIFI 2700 stereo decoder and memories

    So pressing a button physically moves the scale pointer too?
  6. kellys_eye

    (1973) Imperial HIFI 2700 stereo decoder and memories

    The voltage on the presets DO change - they switch between fixed values depending on where the individual tuning preset is set to. It would also change if you adjusted the control manually - like when you set each preset to the required station.
  7. kellys_eye

    (1973) Imperial HIFI 2700 stereo decoder and memories

    You can get 0.15μF capacitors as tantalums. Where are they located in the circuit?
  8. kellys_eye

    Sony Bravia picture problem

    If the fault is identical on separate video signal inputs then it's not related specifically to the bit rate of the internet connection but within the signal processing circuitry itself - possibly indicative of a dropped 'bit' in a parallel bus. You might try to find the 'secret code' access to...
  9. kellys_eye

    Sound Dynamics subwoofer schematics

    Got any pics of the parts? Does the pot have three terminals? If so, measure between the two outer, then measure between one outer and the middle pin and, whilst adjusting the control, see if the resistance value changes. Do this from the other outer pin (to centre pin) too. Let us know your...
  10. kellys_eye

    Wireless proximity detector that goes off when blocked

    Weigh scales - alarm on minimum weight.
  11. kellys_eye

    Sony Bravia picture problem

    Picture quality over streaming services can vary with bit rate and the 'fault' you indicate is indicitive of this process. Try the set with other external inputs of known quality and see if there are any other indications.
  12. kellys_eye

    Positively charged "holes"?

    Mine would just say "what are you wasting your time on that for?..." :rolleyes:
  13. kellys_eye

    Solar astronomy taken to a new level for me

    Any form of astro photography floats my boat. Been a keen astronomer for years but, strangely, when I moved to my present location (one of the darkest night sky areas in the country) I've hardly taken the opportunity to set the 'scope up..... Love the solar image - have you been doing it long...
  14. kellys_eye

    (Please help) Portable solar powered powerbank

    You haven't done 60% of the work at all. You haven't shown us anything (other than a useless flow diagram) - all you've done is describe what you WANT to do. If you consider the 'pointing out the obvious' to be hostile then you are surely of the snowflake classification? When (if) you get your...
  15. kellys_eye

    Positively charged "holes"?

    which makes 'us' GODS!!!!!!! I never knew :p:D
  16. kellys_eye

    (1973) Imperial HIFI 2700 stereo decoder and memories

    P106 looks to be a large (physically large - to get a long resistive track) potentiometer coupled to the back of the main tuning capacitor. This would be used to develop the fully-variable tuning voltage required for the normal FM tuned range. The innards may even include some form of...
  17. kellys_eye

    (1973) Imperial HIFI 2700 stereo decoder and memories

    P108 sets the main tuning voltage to the switched presets. The presets are (or at least were) commonly used in TV tuners too - the spiral shaft holding the wiper of the potentiometer and adjustable via the push button (pull it out to adjust?). You will have a DC voltage at the wiper of P108 -...
  18. kellys_eye

    Help identifying unknown component (SMD Diode?)

    Bah.... Vote ELECTRONS for 2020......
  19. kellys_eye

    Odd Behavior of Circuit

    The bell may draw an initial high consumption that caused a spike 'low' to occur. Equally such bells are notorious for introducing back EMF (being simple mechanical contacts operating an inductive load) so some form of suppression would be required.
  20. kellys_eye

    (Basic Question) Two Circuits on the Same Power Supply

    Two identical fans will consume the battery at twice the rate of one fan. Both will run at identical speeds (when wired in parallel). The microphones can be powered by a simple regulator circuit to convert the 12V to 5V (5V being more convenient and harmless to the circuit) using a device like...
Top