I've been wanting a Pi 400 since it released, but haven't been able to bring myself to pick one up. I even had one in my hand at Microcenter in Cleveland Ohio a few months back. I always felt too guilty to get myself anything in my life, and that was true of the Pi. I finally decided that I just need to do it already. I had a good paycheck, all my bills are covered until next pay, I really want to start working on this project, and I know if I don't do it now, I may never do it. It's gotten far easier to justify though, since Vilros released the Pidock 40p that turns the Pi 400 into a laptop. It lacks a battery or speakers, but has everything else I need. Seeing as I'm looking to travel the country, I need a compact and convenient way to carry a Pi 400 with me. I could have used the 7" touchscreen and a Pi 4, but that's not the intended platform for this cartridge format. I need actual hardware. Carrying around a Pi 400 and a portable monitor sounds like as huge hassle to me, which is a major reason I've been hesitant to get anything.

The Pidock 400 requires 12 volts, which isn't as common as 5 volts from USB, but it means I have plenty of power options. Renogy makes a massive power bank that outputs 5 volts through USB as well as 12 volts. It's 72,000mah capacity is collosal and could run the Pi 400 for maybe 24 hours if my crude math is correct. Add the screen of the Pidock and it will probably be something closer to 12 hours. Still, 12+ hours on a charge would be fantastic. I could easily spend an entire day working out in the desert or mountains somewhere, and. It worry about power. It can also take in 100 wats from a solar panel, so I'll be buying a panel for it as well. I haven't ordered the battery bank as it's about $180, and I don't need it right now. I really like that the system takes 12 volts. I can easily pull that from a solar panel, motorcycle battery, battery bank, vehicles, and anywhere else that harbors 12 volts DC. The battery bank can charge from 12 volts DC as well, which means I could just plug it into the motorcycle and let it charge while I ride. Very exciting stuff. 

I should have the Pi and Pidock in less than a week. I'll get it set up and updated, as well as get some more updates posted. Next up is a soldering iron so I can finish assembling my prototype carts. I'd love to test the carts in the next few weeks so I can get started on development. I've kept extensive notes on ideas, problems, and solutions since I began this project, so it's a matter of getting them out and reading back through. 

The current plan so far goes as follows:

Get Pi and Pidock working with stock Raspberry Pi OS image.

Solder memory chips onto the PiHAT prototyping boards.

Test memory chips on Pi 400.

Flash EEPROM on PiHAT boards to tell the Pi what pins to use and how to set them up.

Set up Pi to load cart EEPROM without rebooting, if possible.

Develop test program to be stored on and loaded from cart.

Develop cart management software to be run on the Pi and handle loading, saving, backing up, and other file operations of carts. 

Develop PCB for custom carts and order a test batch.

Develop case for carts using PCBs, order test batch.

Develop advanced cart with extra hardware such as microcontroller and environmental sensors.

Continue developing software and cartridges.

This is a massive project for me, but ordering the development hardware is the biggest step I've taken so far. It was $360+ for the Pi 400(full kit), the Pidock 400, and shipping. I don't spend that kind of money lightly, but I want to get back to this and finish this project. Spending that kind of money will force me to take it seriously, and give me a default activity aside from sleeping and watching tv. I don't have much to be excited for when I get home every day, so I finally gave myself something. I plan to use this Pi laptop as an every day computer as well. I already use a laptop from 2013 running Linux, so it's really not much of a jump to the Pi 400. I've used a Pi 4 as an every day computer and it was fine. YouTube playback wasn't great, but I know ways around that. Like using my phone. I want to simulate real world use of the Pi 400 as I develop for it so I can find any sort of weird problems. It would be easy to develop on a clean system image, but that's not realistic, and not how I want to do things. I plan to develop for the Pi 400 just as it comes out of the box, aside from updating the default software. I'm incredibly excited and can't wait to post the big update when the hardware arrives. Off to choose a soldering iron now. One of the last missing pieces.