Still unclear how I will proceed on PiDP10 power switch hack; printed three more PCB handles for EDUC-8

HAD A SUGGESTION HOW TO RESOLVE KEYSWITCH ISSUE

One of the other builders of this kit saw my post about the inability of the modern USB-C power supplies to provide power to a 'dumb' receptacle because they need to negotiate voltage and current with the device they will power. 

He mentioned that the Raspberry Pi 5 has a jumper which can be momentarily shorted to act like the 'Power on' button of the Pi. This is not the same behavior as expected with the hack - switch turns on machine while the key is in one position and turns off when put in the other position. The jumper can cause the machine to power up if it has been powered down before, but it won't cause it to power down. Further, it can't be continuously shorted by the switch turned to the On position, instead it should be a short connection. 

ONE OPTION IS TO BUY ANOTHER POWER SUPPLY BUILT FOR 5V DUMB CONNECTIONS

If I buy a supply that only provides 5V and does not engage in the protocol negotiation like smarter supplies, then it will deliver power as intended. It needs to provide enough current for the RPi 5 plus the PiDP 10 electronics, USB keyboard and USB mouse. which is around 5A total. 

THE HACK DOES NOT PROVIDE THE IDEAL FUNCTION I WOULD WANT

I wish that the keyswitch would power on and run when switched to ON and left in that position. I would like it to signal the RPi5 to fire off a Linux shutdown command to cleanly terminate operations and ensure all file systems remain uncorrupted, then power down. This would require some code running in the Debian Linux on the Pi and a different wiring. The keyswitch as it is currently wired will just immediately drop power when switched to the OFF position. 

In fact, the PiDP10 environment requires that the user carefully manage shutdown of the PDP10 software it is emulating as well as the Debian Linux of the underlying RPi, as both have file systems that can be damaged if not shut down cleanly.

When running ITS on the PDP10, I first have to issue the 5down command and wait five minutes until the operating system quiesces. Then I have to issue a shutdown command to Linux which ultimately causes the RPi to power down after quiescing its OS. 

Thus I guess a real ideal solution will issue the shutdown to whatever OS is running on the emulated PDP10, then shutdown the Linux on the Pi and finally power down. Lots of software hacking involved. 

NOT SURE WHICH DIRECTION I WILL GO

Because this is not an ideal power switch solution, I am not sure what I will do. I might leave the machine as it was, ignoring the keyswitch I installed. I might buy a different power supply to implement the keyswitch hack as it exists. I am unlikely to bother engineering the ideal solution. 

THREE MORE HANDLES PRINTED TODAY

As long as I remember to fire off the next print job regularly, I can have the printer working away while I attend to other tasks in the workshop. 

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