Today I bought a new HDMI screen and connected everything up. I now have a working Rasbian computer with wireless mouse and keyboard. I’m well chuffed.
I’d like to do a lot more on it, like wire in the USB sockets on the top of the case, which isn’t horribly difficult. Right now, though, ZipPi is a functional, dedicated computer. It may be a Raspberry Pi 3 soon.
ZipPi the Raspberry Pi computer now has a MOSFET and board, and uses two case LEDs that indicate power to the board, and power to the Pi. It boots up, and we have played with it, but it needs a dedicated screen, mouse and keyboard, and a wireless dongle. I might get something with a decent antenna, or I might just get the Pi Dongle again. Those have to be extended out the back so I can close up the aluminium case and have it done. The board also has to be mounted inside its allotted hidden dead space. It works, though. And nothing burned down.
The MOSFET I wanted to use doesn’t provide much current at 5V. I’d seen the graph but my eyes had passed over it until Mat read it off, and then I understood what it meant and why it was important. And, y’know, why I should pay attention to the fact that graph is an upward curve. More voltage means more current – and I want to run the Pi at 5V through the USB power supply. It’ll protect it best, and allows for most flexibility. .7A is not enough.
Mat gave me the right sort of MOSFET, although he did insist on breadboarding it himself. I say I’m just teaching silicon to respect me.
Learning out of this: graphs are probably important. I should look at them or something.
It’s hard to make a MOSFET latch on and half-on, but I did it.
I made an initial list of hardware for the first build, which is the ordinary stuff like ‘raspberry pi’ and ‘SD card’. The big case is completely dismantled, and all useful parts I could get to easily have been stripped off. I now have far too many heat sinks, but I may use one on Itchy anyhow.
I’m not anticipating big problems, although I’m going to have to grab some extension cables for the USB dongles and the Cat5.
I’ve had another look at the case I want to put ZipPi into, and it’s already got separate power and reset switches, so I’ll probably use those. Which I should have all along. I still want to make a power switch for a separate, smaller case, but ZipPi the Computer will probably have the external hardware kept working.
As it turns out, a power supply with a switching MOSFET is probably unregulated and probably going to be passing a lot of electrons around really really fast. So, it gets hot.
I have holes in my breadboard that are not how they were originally designed.
I have the theme tune to Skippy the Bush Kangaroo in my head. ‘ZipPi the friend ever true…’
The Pi-based building a computer project needs a name. It’s really just a bunch of small, separate solutions. Everything takes input or is there for output, and I just need to join things up.
Solutions -> Pi Lab/Lab Bench/Benchtop Pi
Joining things -> Sew What?/Popper Pi/Glue Sniffer/ZipPi.
ZipPi. I like ZipPi. At some point the spelling may change, or the capital letter may be decapitated, or I might decide it’s too much like Sparky, but for now, it’s ZipPi, pronounced Zippy.