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  1. Alec_t

    12v Fan Reduce speed in every minute interval using 555 timer.

    How many wires does your 'normal' DC fan have? 2,3,4,6?
  2. Alec_t

    How to switch something as soon as power is applied

    Apart from invalidating any warranty, would such a wiring mod also invalidate the driver's insurance (it would this side of the pond)?
  3. Alec_t

    Simple stall over current 12v dc motor protection?

    Have you tried a slow-blow fuse? Whatever you use will be a compromise, since it will have to allow the motor to get up to speed from a stopped/stall state.
  4. Alec_t

    12v Fan Reduce speed in every minute interval using 555 timer.

    Welcome to EP! Does the fan have a speed-control input? Model/specification?
  5. Alec_t

    pwm opinions

    Are you using gate resistors to suppress any HF oscillation?
  6. Alec_t

    Changeover Switch Relay?

    This one looks a better bet, but I doubt it could handle your motor(s) directly.
  7. Alec_t

    Changeover Switch Relay?

    Stall current is the current when the motor is stalled (i.e stationary) but power is applied, such as at start-up. It is many (perhaps 5 or more) times the running current (i.e. the current when the motor is up to full speed). Your relay contacts need to be rated to handle at least the stall...
  8. Alec_t

    Changeover Switch Relay?

    I second the use of an impulse relay (driving secondary relays or contactors or SSRs). Is 10A the motor run current or its stall current?
  9. Alec_t

    Windows 10...opinions?

    My recently-purchased lappy came with Win8.1, which is all apps-and-buttons-oriented and pretending to be a tablet. I didn't particularly like that, having been used to XP, so went for the Win10 offer. It installed without a hitch. No probs so far. It gives you the option of a tablet-mode...
  10. Alec_t

    Cadillac Intrusion Sensor

    I think leaving it just cut is unlikely to work, since the wire is described as a 'signal' wire. If you're going to risk connecting the trigger wire to either battery positive or the negative line (which could be either Pin B or Pin C, but my guess would be Pin C), then you could do so via a...
  11. Alec_t

    Burnt out Blanket Controller

    Welcome to EP! Further info needed. Brand/model number/schematic?
  12. Alec_t

    Need a Relay with Timer

    Welcome to EP! If the relay has form C contacts then won't the normally-closed contact do what you want? BTW, that Omron one only offers a delay up to 0.5 secs. There are lots of time delay relays listed by the main component distributors (Farnell, Mouser etc) which would seem to meet your...
  13. Alec_t

    I have found free energy...sorta...

    Here in Cardiff the hot air generated by our National Assembly members in their debating chamber (siambr) is indirectly used to save energy :). The Assembly building has a cowl on the roof so that hot air rising creates a negative pressure to induce a cool air inflow, thus reducing the energy...
  14. Alec_t

    Charging Batteries using a Power Supply

    If the max specified is 1.75A I'd use something less, say 1.5A, hopefully to prolong the life of the batteries.
  15. Alec_t

    Cadillac Intrusion Sensor

    Do you have a wiring diagram of your Caddy? If we know what connects to all the three pins of the sensor (presumably two of them are the power supply) it might help to decide how to fool the Caddy. I see the maker of the sensor (May & Scofield of Basingstoke, UK) is still in business. There's a...
  16. Alec_t

    Cadillac Intrusion Sensor

    Are there any type/part numbers or other markings to identify the sensor? If so, some technical info might be found by googling, or availble from the manufacturer.
  17. Alec_t

    I need help building a solenoid controled by a rheostat

    This was the sort of thing I was suggesting :-
  18. Alec_t

    Help Identifying a Thermistor? (I have temps and Ohms)

    Thermistors are generally specified by their resistance at 25C (= 77F), so your readings tie in with it being a 5k one.
  19. Alec_t

    Bracelet That Pings A Nearby Ring [Help]

    Welcome to EP! Even if you have access to a micro-assembly robot I'm afraid this project isn't practical :(. The Laws of Physics are against you, in that any RF energy harvested will be incredibly low and unlikely to be able to turn on an LED, yet alone power a transmitter.
  20. Alec_t

    Controlling Motor with 0-10V input

    If you use an off-the-shelf controller for the brushless motor it will have a speed control input which might accept PWM or a 0-5V analogue input. Check datasheets for candidate controllers.
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