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  1. KrisBlueNZ

    Bicycle Turn Signal Electronics needed.

    Good advice duke. Potting resin is probably a good way to construct it. You'd have to use a fully enclosed control switch. You could probably drill and tap some holes into it afterwards, and use a pipe clamp to fasten it onto the bike. Or would the resin crack from the strain?
  2. KrisBlueNZ

    Bicycle Turn Signal Electronics needed.

    I've seen circuits that do, and circuits that don't, decouple pin 5. It's not really high impedance; it connects part way down the three-resistor voltage divider that sets the upper and lower threshold voltages, and the resistors in the divider are nominally 5k each - at least, they are 5k each...
  3. KrisBlueNZ

    Help with a logic LED testing circuit 4049 IC question.

    Like you said, the negative side of your input voltage goes to the common ground rail, VSS, the negative side of your 5V supply. You have the input voltage shorted out because your diagram shows the +ve side of the input voltage connecting to the bottom end of the resistor, which is grounded...
  4. KrisBlueNZ

    SMPS boost regulator using a schmitt trigger oscillator

    That's brilliant Steve! Could you post an updated list of component values? Has the schematic changed at all? What value and type of inductor are you using? Are you still using the same rectifier? Now that you've fixed the errors, have you tried applying the feedback at the capacitor again...
  5. KrisBlueNZ

    Bicycle Turn Signal Electronics needed.

    Hi Ernst, Putting the switch inside the controller, and using an internal battery, and removing the hazard flash option, all simplify the circuit a lot. This circuit will work from any voltage from 6V to 12V. The absolute maximum is 15V (exceed that and the 555 may be damaged). The only...
  6. KrisBlueNZ

    Bicycle Turn Signal Electronics needed.

    Hi Ernst. I've designed something for you to get the detailed discussion started. This is a controller module that may do what you want. Please have a look at it, and my description, and tell me what changes, if any, you want to see. Also anyone else on this thread, please add your...
  7. KrisBlueNZ

    Bat Detector Load Issue

    I think you can simplify your design quite a bit if you want to. I don't think you need that complicated high-current rail splitter. The only components that really need a centre rail are the three op-amp inputs (the two amplifiers, and the comparator). This could be easily handled by a voltage...
  8. KrisBlueNZ

    Motor control diy

    Yes, as duke37 says, you can't reverse an AC motor by reversing its power connections. It has to be a DC motor.
  9. KrisBlueNZ

    SMPS boost regulator using a schmitt trigger oscillator

    That's an interesting idea. I'd be interested to know whether it works once you've installed a good battery. I kind of suspect it won't work very well. I think it's better to generate the control waveform independently of the voltage comparison. I was going to upload what I thought was a nice...
  10. KrisBlueNZ

    SMPS boost regulator using a schmitt trigger oscillator

    Cool Steve :-) I like circuits that look simple but have some level of ingenuity behind them. Your design has a low component count but still has closed loop voltage regulation. As I understand it, your circuit uses on/off control of a fixed duty cycle signal; since U1A's output is a...
  11. KrisBlueNZ

    SMPS boost regulator using a schmitt trigger oscillator

    That's interesting Steve. I would be interested to see the schematic too.
  12. KrisBlueNZ

    1V/Oct Control for oscillator

    I think you'll find it very hard to avoid pressing two keys simultaneously! You'll need a pretty exact voltage for your resistor chain. A fixed regulator will only be accurate to a few percent. The current through the chain won't be high, so I would use a small variable regulator such as a...
  13. KrisBlueNZ

    Problems substituting a relay

    Yes, that would be a good solution. I will suggest that to them.
  14. KrisBlueNZ

    1V/Oct Control for oscillator

    All the resistors need to be the same value. For five octaves you'll actually need only 59 resistors, because you only need a resistor BETWEEN semitones. The bottom and top keys are the ENDS of the string. But you've got the right idea. You haven't addressed the issue I raised about contact...
  15. KrisBlueNZ

    1V/Oct Control for oscillator

    Yes, that's a resistor chain. It's the type I described in the paragraph starting with "Another approach ...". If you press two keys simultaneously, you get an output voltage that doesn't correspond to either key; most of the time, it won't be an exact semitone voltage either. Yes, you can and...
  16. KrisBlueNZ

    Problems substituting a relay

    That partly explains why the software wants a peak voltage value, but IMO it doesn't excuse the unintuitive dialogue box. This is a shame because generally I've found LTspice IV to be very intuitive and nicely implemented. The dialogue box allows you to select the "function" (pulse, sine, exp...
  17. KrisBlueNZ

    1V/Oct Control for oscillator

    The best way is digitally. You can pick up MIDI keyboards fairly cheaply. You may be able to buy or find a design for a MIDI to control voltage converter that will produce a voltage that follows the 1V/octave convention, and a gate signal. If you want to get into microcontrollers, you can make...
  18. KrisBlueNZ

    Problems substituting a relay

    I think it's non-intuitive. AC sinewave voltages are pretty much always specified by their RMS value. The least they should do is clearly point out that it's the PEAK value you're entering, not the RMS value.
  19. KrisBlueNZ

    Problems substituting a relay

    Sorry to flog a dead thread, but I've just discovered another mistake in my simulation. In LTSpice, a sinewave AC source with a "voltage" of 230V actually has a PEAK voltage of 230V, not an RMS voltage of 230V. If you want a 230V RMS voltage source, you have to specify a voltage of 325V. "Go...
  20. KrisBlueNZ

    What value of resistors do I need and a sanity check

    RL and RB are used to provide currents of around 1 mA for the switched LED and the voltage reference LED. The values have to be adjusted according to the battery voltage used. These changes could be avoided if they were replaced with constant current sources. There used to be the 1N5283 series...
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