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Filippo Federici edited this page Oct 22, 2024 · 6 revisions

Overview

Inside a PiGun there are two electronic boards. The first one, located in the handle divides and distributes power to the different components. The second one is the main board, located in the underbarrel area, which hosts the Pi Zero and other circuitry needed for PiGun operation.

Power Supply Board

The power supply board is powered by a 24V source and has three terminal outputs for 24V, 5V and ground. The 24V line will power the recoil solenoid system, while the 5V line powers the Pi. It is possible to simplify greatly the whole design by using only 5V for everything, but the recoil would be quite lame.

This board is simple enough that we did not find it reasonable to design a dedicated PCB and have it manufactured.

Parts

parts required for the power supply board

Important

  • Any voltage regulator could do, as long as it fits in the handle.
  • The M2 mounting holes on the PiGun handle are positioned to match the holes on this perfboard.

Instructions

  1. solder four male headers on the perfboard, to host the LM2596

Important

The headers must be positioned to fit in the through holes of the LM2596 board.

  1. solder wire connector
  2. solder the wires connecting the LM2596 input and output to the wire connector
  3. solder the LM2596 board to the male headers

Note

This is very inelegant because the LM2596 will be permanently attached to the board, but with female headers it will stick out too much and the handle would not close properly.

Main Board

The main board hosts the Pi Zero W, circuits and some buttons that make the whole thing work.

Parts

  • female header for RPi (2x20 2.54mm pitch)
  • n-type MOSFET (high current)
  • diode
  • NE555 timer (dip 8)
  • PC817 optocoupler (dip 4)
  • IC socket (one dip 14 or one dip 4 and one dip 8)
  • three colored LEDs, 3mm diameter (recommended red, yellow and green)
  • tactile switches 6x6x5mm x6
  • CDR two-positions connectors x6, right-angle
  • capactors:
    • 10 nF x1
    • 100 uF x1
  • resistors:
    • 330 ohm x3
    • 220 ohm x3
    • 75 ohm x1
    • ...

If making the board from scratch instead of buying the PCB, these are also needed:

  • solid-core wires
  • Elegoo perfboard, dual-sided, 5x7cm

Instructions

PiGun 1F PCB

The repo includes a PCB design that can be submitted to a manufacturer (like JLPCB or Aisler) and shipped at a moderate cost. This design does not include sockets, connectors or other components: you will have to solder them yourself on the PCB. However, the wiring is printed in the PCB copper layers, which eases the pain.

  • picture of the PCB

Full DIY Solution

Before designing a PCB, early PiGun prototypes featured a home-made main board, soldered on a perforated board.

  • picture of the board schematics

Warning

The following components connect to the physical parts of PiGun, therefore they should be soldered exactly where indicated in the schematics:

  • LEDs
  • tactile switches
  • Pi Zero female headers

Not going to give much more instructions here, it is pretty straightforward: just make it as in the figure.

There will be some serious amount of soldering to do, good luck!

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