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I have a prototype board like this:

enter image description here

I have a breakout board like this:

enter image description here

I would like to solder the breakout board directly on top of the prototype board without using headers, so that I can reduce the height of my prototype.

  1. I am aware of edge castellation, but would prefer to explore an explore an alternative as I do not have access to anything besides the protoboard, breakout board, soldering iron and solder .
  2. I would like to avoid using headers to keep the height of my prototype small.

Is it naive to think that I can just put solder or wire in the holes of both the Protoboard and breakout board, and get them to sit ? I can probably add some glue also to hold the boards together. Is this a bad idea ?

I do not expect much mechanical stress, as I will secure the prototype board to the case.

Any suggestion ? As I am just hacking a prototype together for demonstration purposes I do not want to go through the trouble of placing all the individual components of the breakout board on the protoboard.

EDIT: I'm trying to keep the footprint as small as possible so do not want to place the boards side by side. I would like to place them one on top of the other and minimize the height as well.

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  • \$\begingroup\$ @jsotola I'm trying to keep the footprint as small as possible. \$\endgroup\$ – Kaizer Sozay Mar 13 at 5:27
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    \$\begingroup\$ You would have to be very careful about shooting things out in the bottom of the board. Kapton tape might work for an insulator. \$\endgroup\$ – Ron Beyer Mar 13 at 5:28
  • \$\begingroup\$ @RonBeyer Can you explain what you mean by "shooting things out" ? Do you mean insulating the breakout board from the PCB ? \$\endgroup\$ – Kaizer Sozay Mar 13 at 5:29
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    \$\begingroup\$ If there are tracks or pads on the back of the breakout board you must make sure that they don't contact anything on the prototype board that is part of your circuit. \$\endgroup\$ – Peter Bennett Mar 13 at 6:16
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    \$\begingroup\$ Insulation tape may work, but beware of any sharp points (like a wire soldered through a hole) on the back of the breakout board - such things may cut through the tape and make an unwanted contact with the prototype board. \$\endgroup\$ – Peter Bennett Mar 13 at 6:24
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Here's my suggestion:

  • As needed, add a sufficient layer of electrical insulation between the bottom of the DRV2605L board assembly and the top of the prototype board.

  • With your pin header assembly, push the plastic insulator all the way down to the far end of the pins without actually removing the insulator from the pins.

  • Position the DRV2605L board onto the prototype board as desired.

  • Insert the pin header from the bottom of the prototype board up through the 0.1" O.C. plated-through holes (VIN, GND, SCL, etc.) on the DRV2605L board. Ensure the pin header's plastic insulator is on the bottom of the prototype board, and the exposed ends of the header's pins protrude out the top of the DRV2605L board.
    (NB: Use a piece of electrical tape to keep the pin header's plastic insulator pressed against the bottom of the prototype board during soldering.)

  • Lay this assembly flat on the workbench with the prototype board on the bottom and the DRV2605L board on top.

  • From the top side of the DRV2605L board, flux the header pins and plated through holes in the PCB, and then solder each pin to the DRV2605L board and to prototype board. When soldering,

    • ensure the soldering pencil's tip touches primarily the header pin, and touches secondarily the PCB pad at the top of the plated-through hole on the DRV2605L board, and
    • touch the solder wire to the header pin—NOT to the soldering pencil's tip—during the soldering process.
      (NB: The header pin must become very hot as it must be the means of heat transfer down into the plated through hole in the prototype board.)
  • After all the pins are soldered and are cooled down, remove the electrical tape that held the plastic insulator to the prototype board, and then pry off and remove the plastic insulator from the now soldered header pins.

  • Inspect each solder joint on the top and bottom, and rework any joints that are unsatisfactory.

  • Remove the flux residue from the assembly.

  • Using a flush cutter tool (a.k.a., wire cutters, diagonal pliers, nippers, etc.), trim off the header pins to the desired height above the surfaces of the two boards.
    (NB: I recommend that you leave a stub height of about 1 mm – 2 mm after cutting each pin. A stub is required if you later need to desolder these pins with a vacuum desoldering rework station.)

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