Running out of ground pins



  • Hello,

    i recently started working with the arduino pro mini and the nrf24L01+ (and more or less with hardware at all).
    The board has 3 ground pins. While wiring up with jumper wires i used one for the nrf chip, one for the battery and one for the voltage regulator.
    My problem is that there now is no ground pin left for the temperature sensor. What are my options here when i do not want to solder? Can i use the BLK pin as ground? Are there some kind of Y shaped jumper wires? Or is there another solution?

    Have a nice sunday šŸ™‚
    Michael


  • Mod

    Welcome to the MySensors community @Osch, great to have you here.

    I haven't seen any great solutions for this, but the best solder-free alternative I have found so far is breadboards. Either regular ones like these or my favourite, the small ones like https://www.aliexpress.com/item/Free-Shipping-wholesale-1pcs-SYB-170-Mini-Solderless-Prototype-Experiment-Test-Breadboard-170-Tie-points-35/32519558901.html

    An alternative can be to build custom y (or even 1-to-many) contacts from header pins (female or male) by connecting a stripped piece of wire to all the pins. The male header pins can be cut to any length you want. The female headers can also be cut, but cutting is a bit tricky so it is better to buy smaller ones, maybe 4 pins wide. Make sure you get a good connection between the stripped wire and the pins, otherwise you might spend a lot of time troubleshooting problems caused by loose connections



  • @Osch Kind of hard to splice small gauge wires without soldering or terminals. A step towards wire splicing without soldering is to buy a wire stripper suitable for small ~20-28 gauge wires like this:

    ā€¢ Small wire nuts (probably the purple ones for 20-28 gauge or so). Requires wire stripper. Just cut jumper wires in half, strip, and twist up 3 or more for more grounds. Wire nuts make excellent connections, maybe use electrical tape to wrap them if there is any concern of tugging on the wires.

    ā€¢ No-strip insulation-displacement connectors aren't likely to work with the tiny stranded wire in your jumpers.

    alt text
    ā€¢ Crimp splice connectors like used for telephone wire splices might work but then you need a decent crimper, although a pliers may do. May be too big for smaller wires.

    ā€¢ Screw terminal blocks can work well for wiring to sensors if you have a place to anchor the block.

    Tim


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