Vendors of Hardware/Software

https://military-fasteners.com/Screws, bolts, fasteners
https://kicad-pcb.org/Open Source Printed Circuit Board (PCB) software
http://parts-express.comMisc. Electronic Parts
https://jlcpcb.com/PCB Manufacturer, China
http://pcbnow.comPCB Manufacturer
http://foamorder.comCushions, Foam Rubber cut to size
http://www.arrow.comElectronic Parts, etc.
http://www.jameco.comElectronic Parts, etc.