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Ehn't the purtiest etch evar, but it'll probably do.
(Some of what loox like gaps are artifacts of playing with overexposure.)
I finished the final (hopefully ;) PCB design! Now I have more time for writing the firmware: bitbucket.org/wizard23/magicshifteros
I'll won't do any eagle design the next weeks ;)
Dépannage informatique Genève pour particuliers, indépendants et PME.
Cours d'informatique Genève
Création site web
Création e-boutique
Référencement web
Marketing 2.0
Gestion de campagnes publicitaires
The component side of the keyboard PCB, which contains much of the internal circuitry.
The 2 large ICs are the top are the display drivers. The square IC roughly in the middle of the PCB is the 80C32 microcontroller, to the right of this is a smaller square IC which is the CCITT modem. The system ROM is the socketed IC in towards the lower left, to the right of that is the 8K RAM. The 2 small ICs at the right are the PLLs to dectect baudot mode tones (1800 and 1400 Hz), with red-painted presets to set the frequencies. The 3 medium-sized ICs in a row to the left of the processor are system I/O ports, below them (near the ROM) are the keyboard column driver and address decoder. The small IC to the left of the display drivers is the contrast control multiplexer. Along the bottom edge of the PCB are an output port to drive the DAC next to it and a pair of quad op-amps ICs (transmit filter to the left, receive filter to the right)
A collection of boards from the tinyCopter project. More information at my blog: www.qwertyboydesign.wordpress.com
Uncut PCB for a couple of projects: IR camera and LED array. Semitransparency of FR4 material can be useful.
Let's find some JTAG pins.
Red: address / data line bus (interface to Broadway)
Blue: RAM / flash
Yellow: DI?
Cyan: USB
Purple: AV
Having used the STM32L Discovery board, I've now got an STM32F4 board. It doesn't have an LCD, but it does have a faster CPU and an on-board accelerometer chip. There's also a DAC interface for audio, which comes out on the 3.5mm stereo jack socket on the right-hand side. The chip is programmed via a serial bootloader from a Linux host.
Laser stripped conductors
Overmold provides additional strain relief to minimize pistoning
Automated welding for unmatched consistency
Welding results in less dielectric shrink-back than soldering
Typical PC motherboard about the 1998 era with an Intel Pentium II processor. The processor of this computer contains 7.5 million transistors on a single chip. This is a Micro-Star International motherboard.
From Dirty PCBs dot com. Dirt cheap, better than adequate quality, simple ordering, good web feedback, any shape you like, the panelising that enables and dirt cheap, yeah really dirt cheap... Which means you give your imagination a chance for minimal risk. One of these panelised boards was more of a rushed test than the other and having received them in the flesh I can instantly see how I might have done it better. But the total order price was $25 for 10 10x10cm of board, which I fit 2 boards into panelised. So it was $12.50 to experiment, get 10 functioning boards and a powerful experiential lesson. That's the real value of dirt cheap. Then there's the other 10 boards that I couldn't be happier with... for $12.50. My next order is already in...
My second printed board, this one much simpler-- a relay circuit for triggering via a microcontroller. 3-pin female header, L-R:
1) Signal
2) +
3) -
I'm happy to provide the complete EAGLE file if anybody is interested.
This uses a Futurlec JQC-3FF-05 relay, and I didn't drill the NC output pad-- just figured I should have a trace for it (?).
I think I turned around this board in under an hour, from the PDF. I'll never use perfboard again, if I don't have to!
UPDATE: re: mightohm's question: the process for making the pcb:
* switch layers in Eagle to display only the top layer, pads, and dimensions,
* "print" and save to PDF,
* in Photoshop, open the PDF at 1200dpi,
* run an action to fill the pad holes and make B+W,
* print with Samsung ML1740:
* 8.5x11 piece of paper with a glossy catalog page taped to it (Sur La Table fwiw),
* printer output set to "transparency" to (hopefully) get more toner,
* cut the pattern out of the middle of the page
* iron onto a slightly over-sized piece of single-sided copper-clad:
* lightly sand with ~220 grit (finest I had around) and cleaned with acetone,
* pre-heated board with iron (piece of paper in between) for ~30s,
* CAREFULLY drop the glossy printout onto the copper, then just as CAREFULLY drop on another (blank) piece of paper, then a paper towel on top of that,
* put the iron on and let it sit for ~30s,
* gently move the iron around, applying pressure for ~1 min,
* remove the paper towel and keep ironing on the paper over the glossy printout for another ~2-10 min (?), maybe moving it around.
* let board cool for a minute,
* drop board into a container with water,
* after a minute, pull paper off and gently scrub off the rest of the pulp with a toothbrush,
* fill gaps/dropouts with an etch-resistant pen,
* drop into ferric chloride bath for a few minutes, checking periodically,
* remove the board and drop immediately into a container with water,
* rinse,
* drill,
* solder,
* circuit check-- pretty much involves cutting solder and scraping down to the fiberglass where solder blobs bridge traces/pads.
* Bob == uncle.