blog.jmp.no

Electronics, coding and hacking. And ADD.

Bluetooth controlled relays

2011
28
December

As if moving to a new house in christmas wasn't enough, I've been ill for a couple of days. You know, just to top it off with something. Dunno what hit me, but it was hard. Now that I'm finally back on my feet, it's time to play with me ole' toys again.

Today's project was a bluetooth-controlled relay module.

Now, just to be clear, I've felt the unforgiving whack from 230VACs many times before, so I'm leaving the relays unconnected for now. I'm trusting the "tock" from the 10 amp relays to be reliable enough.

The bluetooth module is a UART bluetooth slave module purchased on eBay ages ago. Never really had the time to play with it, so now was the perfect chance to get my money's worth out of it. The relay board operates on 5V, and can be driven directly by the micro controller, which in this case is an ATmega128. The LCD display is not yet in use, but might be interfaced later.


Bluetooth controlled relays
Driven by a 9V battery at the moment

This was very straight-forward. After writing a simple UART program to interface the bluetooth module, it was only a matter of parsing the input and setting the PORTA pins accordingly. Honestly, this was about an hour of work, but the end result makes it seem like so much more.

Now, all I need to do is to grow a pair, and be a man enough to hook up some household items to this thing...


Boxes, everywhere! Everywhere, I say!

2011
15
December

I'm gradually starting to see the tip of the iceberg, now that we've unpacked a few boxes. Still lots of stuff to do, like cleaning out the previous place, but at least I'm getting installed where I'll be the next 100 years (because I'm not doing this ever again)

Getting there..

Mac's up, oscilloscope and some of the part racks are in place, but there's still about a metric ton of stuff missing. And I also need a proper soldering station, that'll be on my wish list for this christmas, I guess.

Stay tuned, lots of interesting stuff will happen soon..


While we're waiting..

2011
7
December

...we might as well do something useful. So, today, I wrote my first Z80 assembly program in many, many years. I keep asking myself why I favor the 6502 so much, when the Z80 is far superior in so many ways. It may not have the same efficiency when it comes to number of operations per clock cycle, but the instruction set is far more advanced and mature. But I guess that's the reason - limitations and restrictions attract me.

I've also studied N-MOS transistors and have designed a simple 4-bit ROM implementation using nothing but N-MOS transistors. I have also designed transistor-capacitor oscillators, LED matrices, and much more. You see, the electronics abstinence is kept under control using the Falstad Circuit Simulator, with the aid of pen, paper and daydreaming. It's actually pretty amazing how intense the urge to play with electronics is, when the real toys are out of reach.

I'm not implying anything, but the next project will certainly be a mess. Literally.


On the move..

2011
1
December

So we're finally on the move, it's finally happening. More or less everything is stored in cardboard boxes here and there, and quite frankly, I have no idea where anything is at the moment. All I know for sure is that my desk is empty, and I have barely touched my workstation in a week.

As soon as I've installed, I'll start experimenting again. The good thing about absence from your hobby, is the inspiration that comes with it. I'm full of ideas, good and silly ones, which I will test out as soon as I'm back. And I'm taking notes.

That's all there is to it for now, you faithful reader(s?) will have to wait for at least another week for an interesting update.

Oh, and Santa, if you're reading this: I need a signal generator and a logic analyzer.


Me, FPGA smitten? Unpossible!

2011
17
November

So I'm already experimenting with multiple FPGA "cores" (in lack of a better term) running simultaneously, interfacing with peripheral equipment and regular day dreaming, with an empty stare, figuring out what's next.

I used to frown upon the FPGA evangelists, with their high-level language and configurable devices. Maybe in the shape of an ASIC, but programmable? No way. But now, I think I'm becoming one of them, and it's frightening how quickly one can change his mind.

I've been studying some rather complex cores lately, for example the FPGA64 and the Apple2FPGA, both very promising hardware emulators, and I keep thinking to myself, "Hell, I can do this! I want to do this!" Now, if someone would sponsor me with an, oh, say Cyclone II board, that'd be great.... :-)

It seems like the perfect intermediate between electronics and programming - it's what I've been waiting for. I'm not a fan of high-level languages, but the thought process behind the design is very low level, and I can live with that. At least, that's how I feel at the moment - as I stated earlier, minds can change rather quickly.

But, let's not get ahead of ourselves here. Runner up is the mini board interfacing a PS/2 keyboard and an LCD display. Get that to work first, then gradually increase the difficulty as I'm noticing the progress.

Eventually, I'll get The Perfect VGA Display DriverTM up and running for the 6502 computer. Oh yes, all I need is spare time, and lots of it.


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