First PCB

I spent many days designing this PCB, at first several times over in Eagle, but could never get the gerbers to work. So I switched to KiCad, where atleast the gerbers was no problem.

I was very hesitant at first, but eventually sent it off to JLCPCB to have it made.

first_pcb0

I know that it is overengineered, but I wanted a flicker-free display where each digit is completely controllable and can be individually addressed. Also wanted the LEDs to shine with the same intensity regardless of how many of them are lit.

It turned out just like I wanted. Nothing at all wrong with the PCB.

clock3

Lately I’ve gone ahead and designed and ordered two more. One dual-channel noise source and a rough draft Z80 prototype board. They have not yet arrived but I expect them within a week or two. I’ve already gone ahead and designed yet one more, but I’ll delay ordering it until I have more designs to order along with it.

Maybe I’m on my way to becoming a PCB master….

The beginning…

A couple of weeks back I started designing my own CPU (called Bizzas CPU) in Quartus II with the initial goal of getting it running on an FPGA. Right now im bouncing between many different tasks as well as trying to just chillax from time to time.

Elements of a CPU such as registers, program counters and ALU‘s are pretty easy to design. I have most of that done. My current task is to design a robust and efficient instruction decoder, or instruction executor as I call it. After that, I will make an instruction loader.

Once those are done, the CPU will hopefully be ready to run inside the FPGA without any significant connections to the outside world. Then the next step is to wire it up to some memory and other peripherals, maybe even make a VGA interface.

End goal is ofcourse world domination!

Here is what a 1-bit ALU block looks like inside:

alu1bit

This particular configuration can do add, subtract, XOR, AND and OR. Not bad for only 7 logic gates.

My project is shared in its entirety on GitHub: https://github.com/joonicks/BizzasCPU

Scrap electronics

IMG_20171105_150434

It wasn’t until just a few days ago that I was informed that the neighbourhood garbage recycling shack had a bin for old electronics. This is spite of telling lots of people that I wanted to get my hands on scrap electronics.

I have been living in this area since before they even started the recycling thing. Im not the one that takes out the garbage (I’m disabled, not lazy).

Right away I grabbed the two DTV boxes = two 80Gig harddrives, the vacuum = 10 AA Ni-MH batteries plus a motor. And I grabbed some coords and power supplies.

Working house monitor

For some time now my house monitor circuit has been working and logging data as well as providing a web interface where the current status of the sensors can be seen. Not that many sensors right now but;

  • Door sensor. Simple aluminium foil pads in the doorframe wired such that if the door is closed, the input pin is directly connected to ground. If the door opens, the connection is broken and through a 5k resistor, the pin is pulled up to +5V.
  • Motion sensor pointed at my hallway and door. To see when people come and go, as well as seeing when I visit the toilet and such… there is no such thing as too much information…
  • Photoresistor underneath my desk lamp. Any time Im at my desk, my desk lamp is lit, so its an indication of wether Im at my desk or not.
  • Dallas 18B20 temperature sensor. Next to my desk (but one shelf up above a server so its constantly reading a bit hotter than the rest of the room).

In the future I hope to expand the system with wires to my window for reading outside temperature and light.

And I have to work on making graphs for trends over the course of a day, month or year for temperature and light sensor readings.

housemonitor1