Wednesday, September 9, 2009

Slow progress.

No recent updates because unfortunately there's nothing exciting to report. I've spent a lot of time hacking and troubleshooting since last week, but I just can't get my flickering LEDs issue resolved.. I've tried rewiring my driver board, I've tried filtering my power lines, I've tried adjusting my power levels, nada. What I have managed to do so far is burn out my microcontroller, which was no fun. I think I accidentally must have discharged a capacitor into the power line when I was trying out different filtering caps. I'm buying the micros from farnell who aren't the cheapest, but easily the fastest. Besides, no one else I've found stocks the pic24s. The chip it self is $17 and delivery is $10, so I ordered 3 to have backups..

My strongest lead at the moment is electronic/signal noise. There sometimes seems to be a correlation to how much flickering there is and how far away from the controller board I hold my hand. That to me indicates magnetic fields and capacitance and stuff. But I also know sometimes you can swear your hands making something happen when it is actually entirely random. What I've started to do is consider getting a couple of PCBs made up for my driver boards.. This would cost about $100 - $120 from, I've read some reviews around and most people seem to suggest they are decent enough. There are lots of places in America that do it and seem to offer more service, but as usual, you typically add US$50 for shipping to Australia. Futurlec is in Thailand so the shipping is almost non existent, for my normal orders under $50 it's $4.

The can of worms that this idea opens up of course is; I've never designed my own PCB, so the last few days has been a crash course in PCB design. I'm still not 100% sure I'll get them made, but I'm probably 80% sure now where as three days ago I was only 50% sure. I had a quick look around on the net for PCB design tools and picked up express pcb, let me tell you here and now: do not use express pcb. I spent about 3 hours making up my first pcb until I realised that this program could not export the industry standard "gerber" files. Instead it uses a propriety file format which, guess what? Only works for orders placed with express pcb. From all accounts their service is reasonable and competitive and the software was easy to learn and use, but locking you into a service with the design software still smells like a dirty trick, plus they charge US$50 for shipping. So needless to say, express pcb has now been uninstalled and I have seen the light of freepcb. Freeware open source and not locked into a manufacturing service. Not quite as intuitive, but so much more powerful, if express pcb was MS paint, freepcb is Photoshop. I'm not going to pretend to be an expert, but it has been a lot of fun getting my feet wet with it, especially once you have the components placed and start routing. The latest freepcb comes with a java app called freerouter which automatically configures the pcb traces, you just sent the links and parameters and the program does the rest, it's amazing, it's borderline a video game, in fact I don't think you would need to do much to it at all to make a game out of it..

So for now I'm going to keep playing with the pcb design and probably in a week or two I'll concede and order a few boards from futurlec. Not really sure what else to try. I'll take some screenshots of my circuit and schematic soon and put them up here.

No comments:

Post a Comment

visitor counter