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  1. BGB

    Audio Generator

    yeah. one can also use some old headphone wires or similar if needed (or earbud wires, or whatever else), and maybe solder into some heavier wire for access to them (headphone wire tends to be very thin enameled stranded wire, to be better for connecting up to stuff, generally want something...
  2. BGB

    Where to buy components?

    generally, I have been buying stuff off Amazon... maybe better is around, but prices are ok for the most part, except that orders go all over the place, so shipping cost is an issue, and it often takes a while for stuff to arrive (several weeks or more, depending on the seller), but it is...
  3. BGB

    Looking for a suitable transmitter

    ( non expert, just stating things as far as I understand them. ) water transmitter... dunno, I would guess maybe try to use comparably high power at low frequency (such as VLF or ULF band), and signaling would likely be by turning the carrier on and off. note that generally, the antenna...
  4. BGB

    Electric motor connections

    yeah, thus far, this looks like probably the most likely answer.
  5. BGB

    Electric motor connections

    between single phase and brushed DC: main obvious difference between them is that a single phase motor will always go the same direction (regardless of input polarity), whereas with DC motors, the direction depends on the polarity of the voltage applied. note that in many applications (where...
  6. BGB

    Electric motor connections

    maybe use a multimeter or similar to probe what connects where. for example, if it is a brushed DC motor (or a series motor), probably there should be two points with very little resistance (across the motor). possibly, some of the other wires could be sensors, such as a thermometer and a...
  7. BGB

    Current limiting strategies for L298N?...

    yeah, nifty. though some of it does seem to assume a specific type of controller (for example, in their C code, and some examples assume the ability to use analog IO and similar). otherwise, still waiting for diodes to show up... (so I can build the stepper driver boards). also now have some...
  8. BGB

    MOSFET H-bridge, weird effect...

    status update: observed that if both sides of the H-bridge are turned on at the same time, then the motor stops without braking. for example: 00=off, break 01=on, forward 10=on, reverse 11=off, floating also, here it is in action (driving the core from a cordless drill), but I didn't notice...
  9. BGB

    Cool circuit plotter with conductive ink

    possible. I was thinking likely both the reservoir/pot and airbrush would need to be at fairly high temperatures (yes, with the metal probably super-heated to some extent). maybe also the brush would need to be heated to some extent, and maybe also the incoming air (such as by coiling the air...
  10. BGB

    Cool circuit plotter with conductive ink

    I think it could be cheaper (and less messy/toxic/corrosive) for "medium-scale" hobby work than buying blanks and doing chemical etching by hand (the PCB blanks seem to be reasonably expensive, as in, several $ per board or so), and not everyone has access to a laser cutter or similar...
  11. BGB

    Cool circuit plotter with conductive ink

    hmm... this leaves me wondering about possibilities of directly extruding with or printing traces with metal of some sort (such as lead or tin), though there would be an issue with getting it to stick well to paper. one idle thought would be using a compressed air source and a venturi, to...
  12. BGB

    MOSFET H-bridge, weird effect...

    yep. I may consider something like this the next time I need some more MOSFETs. for right now, I have 18 remaining N-MOSFETs and 8 remaining P-MOSFETs. I originally found the ones I got partly as at the time I had considered the possibility of building a CNC welder / plasma cutter /...
  13. BGB

    MOSFET H-bridge, weird effect...

    those could also work for low-power uses, though with a drawback of being surface-mount (most of what I am doing thus far is through-hole, no real good way to do SMD at present). I used slightly bigger TO-220 style MOSFETs in the H-bridge I had built recently. but, I meant for full...
  14. BGB

    MOSFET H-bridge, weird effect...

    the L298 was a reasonably cost-effective option though. most other options cost more. the issue mostly is that saturating some of the transistors I have takes a lot of current, and it may be difficult to get enough hFE from low-power inputs to generate enough current to drive them (say, if we...
  15. BGB

    MOSFET H-bridge, weird effect...

    could be. I didn't use flyback diodes before, as I don't have any yet. I had basically tried suppressing the voltage spikes in some of them using capacitors, but mostly this just seems to reduce PDM induced squealing. does it make a difference if my past H-bridges didn't get enough gain to...
  16. BGB

    MOSFET H-bridge, weird effect...

    yeah. I guess the uncertainty is how braking would effect things like RPM and torque in the case of PWM or PDM driving, or if it poses a risk to the motor or similar. I guess potentially, it could either adversely effect PDM driving, or maybe alternatively make it easier to achieve a...
  17. BGB

    MOSFET H-bridge, weird effect...

    built an H-bridge, and something very odd happens... namely, normally, when the power is connected directly to the motor, it spins up, and when power is disconnected, the motor slows and stops over a period of around 1 second or so. similar also happens with my other H-bridges. however, when...
  18. BGB

    Current limiting strategies for L298N?...

    yes, that is the correct motor. info I have on the motors: detent torque: 0.40 Nm step torque: 1.0 Nm rated current: 1.3 A step: 1.8 degrees (200 steps per revolution) rated RPM: 600 RPM (from Chinese sites) voltage: 24v (also from Chinese sites) (measured) resistance: approx 3 ohm IIRC. cost...
  19. BGB

    Current limiting strategies for L298N?...

    I spent $4 each for the L298N by itself (I found some for around $3.95 each on Amazon, though the price is now $4.50 each). so, this was around $16 for 4 of them. if I had bought 4x L297 as well, it would have added a fair bit to the cost. with the L297, a clock pulse still needs to be sent...
  20. BGB

    Current limiting strategies for L298N?...

    I could have bought the L297, but that adds a little more cost, and you still need to give the thing accurately timed pulses, so it is about the same between using software PDM and an L297, apart from maybe saving a few GPIO pins and similar with the L297. the RPi's SoC is 700MHz, so raw speed...
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