Search results

Search Forums New Posts
  1. KrisBlueNZ

    supply voltage for the sensor

    I don't understand the question. We need a lot more information. What Hall sensor? Post links to the data acquisition system and the Hall sensor. Post a schematic diagram of what you have so far. What power supplies are you considering?
  2. KrisBlueNZ

    help with a small project - precise 1rpm motor & circut

    Since you're using this for star tracking, you clearly want something very accurate. I would use a stepper motor running faster than 1 RPM and gear it down to 1 RPM. A stepper motor is controlled by a logic circuit, often a microcontroller, and driven by MOSFETs. Each time the control signal...
  3. KrisBlueNZ

    Curious about the 4060 integrated circuit

    No problem
  4. KrisBlueNZ

    Curious about the 4060 integrated circuit

    A flip-flop can store one bit of information. It is like a memory location with one bit of storage. http://en.wikipedia.org/wiki/Flip_flop_(electronics) There are several types of flip-flops and latches. D-type (CD4013, dual, 74HC374, octal), JK (CD4027, dual), SR (set-reset) and transparent...
  5. KrisBlueNZ

    Curious about the 4060 integrated circuit

    Right, I wouldn't put a crystal oscillator on breadboard. For experimenting, you can just bend the IC leads up and solder the crystal, capacitors and resistors directly onto them. I don't know if crystal-based clocks would be less accurate than wristwatches. I haven't done any testing. Yes...
  6. KrisBlueNZ

    PWM circuit

    Probably, but I don't think that's a very good design. There are much better options available. Linear Technology makes the LTC6992, a versatile device that includes the oscillator and open-loop pulse-width modulator, that would be perfect for this application. Digikey have an evaluation board...
  7. KrisBlueNZ

    Curious about the 4060 integrated circuit

    Yes, stray capacitance is capacitance between PCB traces. If you have a groundplane, keep it away from the crystal oscillator. There's also the capacitance of the gate input on the 4060 which is a few pF. Right, with a crystal specified for 12.5 pF loading I would use 22 pF or 18 pF caps. Re...
  8. KrisBlueNZ

    Stepper/sequencing relay circuit

    Sorry about that. I think there's a bug with the forum software. I've had that problem before. It should be OK now. No problem. I still need to know how the switch is wired to the seat heaters so I can draw the 4-pin connector onto the diagram.
  9. KrisBlueNZ

    Mysterious diode identification help!

    Anything you do that stops it from blowing fuses is a good thing. I don't see how you could have connected the inductor or transducer wrongly. But it's interesting that your replacement transducer might not be a proper match. I have no experience with high power ultrasonic transducers so I'm...
  10. KrisBlueNZ

    Curious about the 4060 integrated circuit

    Yes it's a convenient timebase. Yes, it doesn't have all the outputs brought out because there aren't enough pins! The designers decided that it was important to have 14 division stages, and they only had 10 pins available for outputs on the 16-pin package (after allocating VDD, VSS, reset, and...
  11. KrisBlueNZ

    Rasberry Pi + Relay

    Well, I'm glad that you want to fully understand what you're doing. You seem to be living up to your username :-) BTW re the jumper between VCC and JD-VCC, I don't know. I found several hits by Googling jumper VCC to JD-VCC but no clarification. It should be covered in the documentation for...
  12. KrisBlueNZ

    Choosing a uC

    Arduino is just AVR with a serial downloader and lots of support software, right? Yes, I'm sure ARM will be a lot more complicated. But it's an architecture worth learning. Most smartphones use ARM cores. I should be learning it too. :-(
  13. KrisBlueNZ

    PWM circuit

    For everyone's reference, here's the schematic. And here's the parts list. R1 = 1k R2 = 47k trimmer R3 = 10k R4 = 33k R5 = 270k R6 = 1M trimmer R7 = 330k R8 = 2M2 R9 = 2k2 R10 = 39k R11 = 100k R12 = 470k R13 = 100k R14 = 5k6 R15 = 390k R16,17 = 100k R18 = 4k7 R19 = 33k R20 = 10R R21 = 470R 2W...
  14. KrisBlueNZ

    Stepper/sequencing relay circuit

    Redesign using latching relays I've come up with a design using latching relays. It's a lot simpler and more robust than the other design. The relays are Omron G2R-2-DC12 types which are available from Farnell I think. These are latching types which retain their state, and have two coils...
  15. KrisBlueNZ

    Curious about the 4060 integrated circuit

    That's about all you can use it for! It's just a ripple carry counter with some gates for making an oscillator with. You can make it divide by a specific number, rather than just powers of two, by ANDing several outputs together and feeding the AND gate output into the reset pin. When the count...
  16. KrisBlueNZ

    Rasberry Pi + Relay

    Driving a relay is a very common and relatively simple thing to do. So I thought a quick Google search would turn up lots of documents that explain it simply, clearly and thoroughly. I was half right - there are lots of documents! The best I found after a quick search was...
  17. KrisBlueNZ

    Choosing a uC

    The source code for simple programs will be identical or very similar. When you start using the built-in peripherals, the differences will be significant. When you get into debugging you will need to become familiar with the architecture and instruction set. A larger processor will have a more...
  18. KrisBlueNZ

    Stepper/sequencing relay circuit

    Here's where I'm up to. I'm afraid there's quite a lot to it. Here's a circuit description. US is a CD4017B CMOS decade counter wired with its fourth output coupled back to its reset input (by DC). It has three states: 0, 1 and 2. State 0 doesn't do anything. The outputs that are active...
  19. KrisBlueNZ

    FM Stereo

    Start by looking --here--. Also try http://en.wikipedia.com/wiki/FM_Broadcasting#Stereo_FM If you listen on a mono radio you get both channels mixed 50-50.
  20. KrisBlueNZ

    Stepper/sequencing relay circuit

    Thanks for that diagram Rich. It doesn't explain much, but it's clear that there are four wires going from the rocker switch to the chair. The question is, how are they driven? Can you see the connections to the rocker switch? Can you trace them out, or take a photo and post it here? From the...
Top