New to building things! I’m building a system that can automatically push nutrients into my plants based on software measurements. So far, everything is going well – but I’m now starting to think about getting off the breadboard and onto a PCB.
I’m looking for a convenient cable type that I could use, to connect 4 peristaltic pumps “at a distance”.
The worst option I can conjure would be to use 4 barrel connectors, one for each pump. but I’m wondering if there isn’t a cleaner way to run a single cable. I had looked into PCIe 8-pin cables, but the molex connectors are very expensive, and I can’t find male to male cables.
What would you guys recommend? I need to run the cable about 4-6 feet away from the unit.
How much current do you need to carry? Ethernet is 4 pairs, and connectors are plentiful and cheap. If you are really running power through a breadboard I sure hope you aren’t using much current, because breadboards weren’t made for current.
If you need up to 5A try aviation connectors, e.g.:
If you really only need 5 because you are using common positive anyway and only need to switch the negative side, you can use a different plug; the aviation connectors come in different pin counts. I’m using 4-pin for CNC stepper motor connections, for instance.
Thanks Michael! I’d never really seen those, look like they’d do the job nicely!
I’m running 12V ~2A. Thing is, though I wrote 4-6 feet, I’d like the ability to run even longer stretches, and I read that CAT5 loses current very quickly.
I’m looking to print some cases for my rig, so I’m hopeful to be able to solder a connector for whatever cable I end up using straight onto the PCBs at either end.
No current running through breadboards! Though my Fritzing model shows it, it’s just for my remedial self to remember what goes together.
2A is more than you want to run over CAT5, yes. Is that 2A per motor, or 2A total?
Note that the 2.1A capacity of 24AWG wire in that table is for loose, unbundled wire. For double-insulated bundled wire, I’d go larger; for you case, I wouldn’t go smaller than 22AWG. I’d suggest 18AWG, especially if one of the wires will see a maximum of 8A because you are providing a single supply to all four motors with a 5-pin connector. If you are using 8-conductor wire, 22AWG is probably fine; or 20AWG for a longer run. (I use 18AWG wire for 3-4A/Ø stepper motors.)
MIDI connectors would be good if you aren’t pulling 8A total across a single wire, they are standard 5-pin DIN; you could provide +12V on one connector, and switch GND with your relay or MOSFET board on the other four. But MIDI cables are designed to be used for signal not power, so they are unlikely to have heavy gauge wire inside, and it’s really four connections plus a shield anyway. So making your own cable makes sense here.
Do use a proper fuse to protect against fire! Your circuit breaker protects only your house wiring, not this circuit. You should have a fuse that will blow before your wire melts or catches fire if you have a short circuit on the motor side of your cables! If you have a single positive supply to your motors that is capable of normally carrying 8A, you could put a 10A fuse inline with the positive supply, because there’s some safety factor…
