3 ms·

A lot of it comes down to being mindful of what you're spending the most time on during assembly, but some of it is just hard-won. But I've learned a lot from r

A lot of it comes down to being mindful of what you're spending the most time on during assembly, but some of it is just hard-won. But I've learned a lot from reading Hackaday. Some simple things that you shouldn't have to learn the hard way (but most people do): Make sure your wiring contacts are electrochemically compatible. Gold-to-gold is safe in almost every household environment. Strain relieve every wire. Solder is not meant to be structural. Every circuit component degrades over time. Heat, humidity, and dust accelerates that process. Make a plan to mitigate the ingress of each, and a plan to account for that degradation. Learn to design simple breakout-board carrier boards. The best breadboard layouts are still worse than a mediocre PCB, because the PCB doesn't have flywires to catch on literally everything. Make sure you include mechanical support points for your designs, and pick the right size and material for your mechanical supports. All of this to say, your hardware thing is a thing first, and an expression of your software/firmware design second. If it cannot physically survive being that physical thing, the elegance or resiliency of your code is meaningless.

andyjohnson0 3y ago
Thank you.
joshspankit 3y ago
Please improve this (I have only dabbled), but I’ll add a couple points as well: - Don’t run data lines and power lines right next to each other (electric signals flow through a field surrounding the trace/wire, not in or on the metal itself) - PCB pros avoid right angles for the same reason. Bevel your corners. (You see examples of this on every board if you’re not sure what I mean) - Verify PCB traces with a multimeter before soldering components to it (or if it’s been assembled by the PCB manufacturer, verify everything before powering it on for the first time)
- petsfed 3y ago
  > - PCB pros avoid right angles for the same reason. Bevel your corners. (You see examples of this on every board if you’re not sure what I mean) If your design suffers from the consequences of this, your reach has probably exceeded your grasp. Its true that you can get noise from sharp corners, but unless you're running SPI at maximum speed, it probably won't cause any bugs in your project. And if you need to run that fast, you're going to run into other, less straightforward signal integrity problems too. PCBs with right angle trances look ugly though. So I might still judge you for it, but only if you also wear white before Memorial Day.
  - jacquesm 3y ago
    And right angle traces are more prone to delamination, which is the major reason why you want to bevel your corners.
    - prabhu-yu 3y ago
      Etching would be difficult. ie, if you bend two traces side by side with 90 degree corner, watch the etching around the corner. ie copper may be left on the inner angle of the 90-degree turn. So, I do not use 90 degree turns for this reason, if not for the EMI reason.
      - jacquesm 3y ago
        Yes, the EMI thing is real but not at typical hobbyist frequency ranges. But the mechanical aspects are far, far more important and right angles are simply a bad idea. Ideally the lines are smoothly flowing (like say at the bottom of the old KIM boards), but that's not how auto routers place the traces. 45 degree angles in succession are a good enough compromise. They're mechanically reasonably strong, they don't delaminate and can be easily placed and used for bus patterns with closely spaced traces that will reliably etch without the outside being eaten up and the inside being 'too late'.
        joshspankit 3y ago
        What frequency ranges does it start to become an issue? Cheap controllers can be on in the hundreds of MHz now.
        petsfed 3y ago
        >The limiting factor that will determine whether any resonances are excited is the size of the square region in a right-angle PCB trace. In particular, the lateral size of the region will be approximately equal to the quarter wavelength of the lowest order resonance, so this gives you a good baseline for estimating the fundamental resonance frequencies. The remaining harmonics will be approximately odd multiples of the fundamental frequency. If we allow a very generous trace width of 30 mils with an effective dielectric constant of 3.5, the lowest order frequency is 112 GHz! If we take this as a knee frequency for a digital signal, this is equivalent to a 3 ps rise time, which is well-below that for commercially available digital components. [0] That whole article addresses the myths surrounding right angle traces pretty effectively. 0. https://www.nwengineeringllc.com/article/right-angle-pcb-traces-its-time-to-kill-the-myths.php https://www.nwengineeringllc.com/article/right-angle-pcb-tra...
- leptons 3y ago
  >Don’t run data lines and power lines right next to each other (electric signals flow through a field surrounding the trace/wire, not in or on the metal itself) Not true. The electrons certainly do travel within the copper. The movement of the electrons generates a magnetic field around the conductor, but the electricity does not "flow through a field surrounding the trace/wire". The electric power absolutely does flow through the metal itself. >PCB pros avoid right angles for the same reason. This is a myth except maybe in very rare cases. Most hobbyists aren't ever going to have a problem with right angle traces. https://www.nwengineeringllc.com/article/right-angle-pcb-traces-its-time-to-kill-the-myths.php https://www.nwengineeringllc.com/article/right-angle-pcb-tra... >Verify PCB traces with a multimeter before soldering components to it (or if it’s been assembled by the PCB manufacturer, verify everything before powering it on for the first time) You should be sure that your design works before sending it to be assembled. If you designed the PCB with proper software that does analysis between the schematic and the PCB design, then there really shouldn't be any surprises that would require you to verify any PCB traces with a multimeter before soldering components. Sure you may have had it manufactured by a crap PCB company, but it's unlikely, PCBs have gotten really easy to make. Software like KiCad if used properly make it practically foolproof to design a PCB that matches the schematic. Designing the schematic is another matter though, it's very easy for a noob to get that part completely wrong and testing PCB traces with a multimeter is not going to fix that. >or if it’s been assembled by the PCB manufacturer, verify everything before powering it on for the first time Not sure what that would accomplish. What are you going to test? Many components can't even be tested unless power is applied. Seems like you're suggesting superstition more than practical knowledge about hardware design and manufacture.

andyjohnson0 3y ago

Thank you.

joshspankit 3y ago

Please improve this (I have only dabbled), but I’ll add a couple points as well: - Don’t run data lines and power lines right next to each other (electric signals flow through a field surrounding the trace/wire, not in or on the metal itself) - PCB pros avoid right angles for the same reason. Bevel your corners. (You see examples of this on every board if you’re not sure what I mean) - Verify PCB traces with a multimeter before soldering components to it (or if it’s been assembled by the PCB manufacturer, verify everything before powering it on for the first time)

petsfed 3y ago
> - PCB pros avoid right angles for the same reason. Bevel your corners. (You see examples of this on every board if you’re not sure what I mean) If your design suffers from the consequences of this, your reach has probably exceeded your grasp. Its true that you can get noise from sharp corners, but unless you're running SPI at maximum speed, it probably won't cause any bugs in your project. And if you need to run that fast, you're going to run into other, less straightforward signal integrity problems too. PCBs with right angle trances look ugly though. So I might still judge you for it, but only if you also wear white before Memorial Day.
- jacquesm 3y ago
  And right angle traces are more prone to delamination, which is the major reason why you want to bevel your corners.
  - prabhu-yu 3y ago
    Etching would be difficult. ie, if you bend two traces side by side with 90 degree corner, watch the etching around the corner. ie copper may be left on the inner angle of the 90-degree turn. So, I do not use 90 degree turns for this reason, if not for the EMI reason.
    - jacquesm 3y ago
      Yes, the EMI thing is real but not at typical hobbyist frequency ranges. But the mechanical aspects are far, far more important and right angles are simply a bad idea. Ideally the lines are smoothly flowing (like say at the bottom of the old KIM boards), but that's not how auto routers place the traces. 45 degree angles in succession are a good enough compromise. They're mechanically reasonably strong, they don't delaminate and can be easily placed and used for bus patterns with closely spaced traces that will reliably etch without the outside being eaten up and the inside being 'too late'.
      - joshspankit 3y ago
        What frequency ranges does it start to become an issue? Cheap controllers can be on in the hundreds of MHz now.
        petsfed 3y ago
        >The limiting factor that will determine whether any resonances are excited is the size of the square region in a right-angle PCB trace. In particular, the lateral size of the region will be approximately equal to the quarter wavelength of the lowest order resonance, so this gives you a good baseline for estimating the fundamental resonance frequencies. The remaining harmonics will be approximately odd multiples of the fundamental frequency. If we allow a very generous trace width of 30 mils with an effective dielectric constant of 3.5, the lowest order frequency is 112 GHz! If we take this as a knee frequency for a digital signal, this is equivalent to a 3 ps rise time, which is well-below that for commercially available digital components. [0] That whole article addresses the myths surrounding right angle traces pretty effectively. 0. https://www.nwengineeringllc.com/article/right-angle-pcb-traces-its-time-to-kill-the-myths.php https://www.nwengineeringllc.com/article/right-angle-pcb-tra...
leptons 3y ago
>Don’t run data lines and power lines right next to each other (electric signals flow through a field surrounding the trace/wire, not in or on the metal itself) Not true. The electrons certainly do travel within the copper. The movement of the electrons generates a magnetic field around the conductor, but the electricity does not "flow through a field surrounding the trace/wire". The electric power absolutely does flow through the metal itself. >PCB pros avoid right angles for the same reason. This is a myth except maybe in very rare cases. Most hobbyists aren't ever going to have a problem with right angle traces. https://www.nwengineeringllc.com/article/right-angle-pcb-traces-its-time-to-kill-the-myths.php https://www.nwengineeringllc.com/article/right-angle-pcb-tra... >Verify PCB traces with a multimeter before soldering components to it (or if it’s been assembled by the PCB manufacturer, verify everything before powering it on for the first time) You should be sure that your design works before sending it to be assembled. If you designed the PCB with proper software that does analysis between the schematic and the PCB design, then there really shouldn't be any surprises that would require you to verify any PCB traces with a multimeter before soldering components. Sure you may have had it manufactured by a crap PCB company, but it's unlikely, PCBs have gotten really easy to make. Software like KiCad if used properly make it practically foolproof to design a PCB that matches the schematic. Designing the schematic is another matter though, it's very easy for a noob to get that part completely wrong and testing PCB traces with a multimeter is not going to fix that. >or if it’s been assembled by the PCB manufacturer, verify everything before powering it on for the first time Not sure what that would accomplish. What are you going to test? Many components can't even be tested unless power is applied. Seems like you're suggesting superstition more than practical knowledge about hardware design and manufacture.