I finally found some time to check out the UCload project. A couple of weeks ago I quickly soldered the PCB and wrote a quick’n’dirty firmware for it. The basic functionality was working, but it wouldn’t do good for the shiny display.
Today I locked myself in my mancave and shut myself off from the world. Turned the light down, pulled loud music from the speakers and started coding like hell!! Not exactly but I found some time to write some more decent firmware for this load. In a previous revision of the PCB I forget the pull up resistors and swapped the SDA and SCL signals. I corrected that and made some small other changes (still ****ed up the silkscreen) in revision 2. The hardware is quite OK and rock solid (prolly more due to the robust FET then my analogue skills :)). However I managed to use a 1n4148 diode to measure the temperature. Connect it to the heat sink and if that one gets to hot turn on a fan. It accuracy is terrible but capable of detecting over temperature :)
Black Mesa Labs has been using a $20 hot plate for a year now for soldering QFN ICs to PCBs. Only issue so far has been the size ( 10″x10″x3″ ) and thermal mass of the thing as it consumes precious microscope work area and unfortunately stays quite hot for 30+ minutes after a quick 4 minute reflow job. BML boards are mostly 1″x1″, so a 800W hot plate with a 6″ diameter heating surface is overkill for most jobs.
Wanting something much smaller for a typical BML PCB – stumbled across this 24V DC heating element on Amazon for only $14. It is rated for 24V at 5-7 ohms ( or 4.8Amps ). A surplus 19.5V DC 5A laptop power brick laying around BML seemed like a perfect match for this element. BML has safety rules avoiding designs above 48V – so the 100Watt 20V DC supply coupled with the 24V element seemed like a great way to make a lot of heat in a small surface area in a short amount of time.
The first batch was a new run of the LivingColors Arduino shield.
The second batch was a breakout board for the NiceRF SX1276 LoRa module. Here I experimented a little with contour routing.
The third batch was an adapter board to use no-name CC2500 modules in boards designed for the Quasar QFM-TRX1-24G. The boards are small (about 20 mm x 25 mm) and the minimal size for dirtypcbs PCB’s is 100 mm x 100 mm. Here I experimented with breakout panels, putting 4 PCB’s in one design.
Most hobbyists use crystals as an external clock signal for a microcontroller. A less common use would be to make a bandpass filter (BPF) for an RF signal. [Dan Watson] explains his crystal ladder design on his blog and links to several sources for understanding the theory and creating your own crystal ladder band pass filter. If you want a set of these purple PCBs you can order them straight from the purple fab.
One of the sources that [Dan] cites is [Larry Benko]’s personal site which is primarily dedicated to amateur radio projects. Which you can find much more in-depth information regarding the design of a xtal BPF. [Larry] goes into detail about the software he uses and some of the applications of crystal ladder filters.
The process includes measuring individual xtals to determine which ones will work together for your target frequency. [Larry] also walks you through the software simulation process using LTSpice. If you aren’t familiar with Spice simulation you can get caught up by checking out the series of Spice articles by our very own [Al Williams].
We have lost something in PCB design over the last few decades. If you open up a piece of electronics from the 1960s you’ll see why. A PCB from that era is a thing of beauty, an organic mass of curving traces, an expression of the engineer’s art hand-crafted in black crêpe paper tape on transparent acetate. Now by comparison a PCB is a functional drawing of precise angles and parallel lines created in a CAD package, and though those of us who made PCBs in both eras welcome the ease of software design wholeheartedly we have to admit; PCBs just ain’t pretty any more.
It doesn’t have to be that way though. Notable among the rebels are Boldport, whose latest board, a tribute to the late linear IC design legend [Bob Pease], slipped out this month. They use their own PCBmodE design software to create beautiful boards as works of art with the flowing lines you’d expect from a PCB created the old-fashioned way.
The board itself is an update to an earlier Boldport design, and features Pease’s LM331 voltage to frequency converter IC converting light intensity to frequency and flashing an LED. It’s one of the application circuits from the datasheet with a little extra to drive the LED. Best of all the kit is a piece of open-source hardware, so you can find all its resources on GitHub.
We are fans of Boldport’s work here at Hackaday, and it should come as no surprise that we have featured them before. From one of their other kits through several different pieces of PCB wall art, to their work making an appearance in Marie Claire magazine they have graced these pages several times, and we hope this latest board will be one of many more.