While it has two speakers and the booklet implies stereo, it’s mono. I thought maybe they goofed on the speaker wiring, but the chip matches a mono NS8002 rather than a TSA2822. Ah well, the risks of re-purposing cheap stuff from Dollarama. Mono works in this application, but I could have used stereo amps elsewhere.
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Work in progress:
Should make a pretty nifty looking bowl once it’s done. Gonna slice about an inch off one end and make that into a lid.
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That’s gorgeous! Is the draw limited to 28"? I’m not huge, but bows with a draw that short are pretty much unusable for me.
Forgot I promised to post the results back in June.
34 panels, 36 microinverters, some racking… at a cost of two 16-hour days of hard labor on the (somewhat treacherous) roof of a burned-out building.
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Thank you!
It’s customary for bowyers to report draw weight at 28" since 28" is the average draw length for an adult using the standard anchor points. My friend Sean draws 33"; his arrows look impossibly long.
That bow could probably be drawn to 30" if it were backed with rawhide- figure another 2# per inch, so it would weigh around 50# at 30". Beyond 30" it would probably start to stack pretty badly and the lower limb would be in danger of failure.
62" is on the short side for a longbow, but that’s what that stave could do. The rule of thumb is to match the bow’s nock to nock length to the archer’s armspan. Longer bows accommodate longer draw lengths without stacking or overstressing the limbs.
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I’ve been working on a home screen program for the Picrate. It might as well display a default something. The colors and look will probably change later. (And my phone is the wrong tool for macro screenshots.) It checks Environment Canada every couple hours during the day (and plays a Protoss Observer sound effect). I’ll add the temp and weather icon in upper right, and well as a temp/humidity sensor I picked up on Friday. I’ll have to see if there’s a way to get push notifications of severe weather alerts. The calendar panel will get hooked into my Google calendar, because why not?
After 11pm, it changes the colors to dark gray on black, because I have too many LEDs in the room already.
I’m using Lazarus / Free Pascal. I can code on my Windows PC, compile and test on my workstation Pi, and copy the executable to the Picrate. Lazarus executables are stand-alone, which is nice for dropping them on a virgin Pi without installing dependencies.
I should get around to githubbing it or something, so other people can use pieces of it.
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Anyone feel like doing some painting?
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Because one of the parts of someone else’s design was just too big to fit in my 3d printer, I modified the shape of the abdomen in this giant posable Halloween spider, splitting it in half using Tinkercad. Then I spent 29+ hours printing everything out using glow-in-the-dark filament and glued it all together.
Here’s the modified pattern on Thingiverse if you want to try printing it yourself.
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Making some of these electrically etched fender washers. I call them “mandalas” although some of them are more like Japanese kamon.
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Those look great! What will you do with them?
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Three of them will be used in a mini guitar amp I’m building – one each for the volume and gain dials, and one for the place where the guitar cord plugs in. I’ll post a pic when it’s done
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My technique: I use 2" zinc-plated fender washers.
It starts with a mask cut w/ a vinyl-cutting machine. I also make circle masks for the back of the washers, to prevent unwanted etching and also to hold the wire in place.
I scrub the front of the washer with steel wool & clean off any fingerprints with acetone, then apply the mask:
The electrolyte is copper sulfate in water, 75g to 300ml then diluted 4:1 with more water. Copper sulfate is available in any hardware store in crystal form, sold as root killer for use in sewer pipes.
Here’s the setup: A power supply set to 5 volts, a variable resistor to control the voltage and prevent everything from melting (really!), a volt meter, a container of electrolyte, and the cathode, which is just any hunk of metal (see photo above; I use a big square plate). I keep the volts to around 3-4 VDC.
A film of coppery sludge forms on the piece, which must periodically be brushed away w/ an old toothbrush.
After a couple hours of this, I shut it all down, peel off the masks, wash and polish w/ my Dremel & wire wheel. Usually then I’ll spray on a clear coat. And that’s it!
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That is the damned coolest thing I’ve seen on BB in a while.
At university, I spent a lot of time making intaglio prints. Then I heard about etching with cupric chloride (CuCl2) which, unlike nitric acid (HNO3), doesn’t produce toxic gases when reacting with zinc. As I prefer not to sacrifice my health for my art, I asked my prof is we could set up a small bath.
The problem with CuCl2 etching is that it’s far slower than nitric acid. Solid lines drawn through asphaltum mask with your standard etching needle take no more than ten minutes with nitric; in the CuCl2 bath, it took a couple hours.
Now I’m wondering if I could’ve accelerated the process with just a little zap.
ETA: Just re-read your post and noticed that this process also took a couple hours. Huh. Perhaps it has something to do with molarity of the solution. Now I wish I could recall my electrochemistry.
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Wash fenders?
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I think with a different power supply, those times could be sped up. Higher voltage or amperage could help, although my electrochemistry knowledge is likewise sparse.
Part of the slowness is these washers are zinc-plated steel – not really an ideal metal for etching with copper sulfate. You can etch brass or copper much more quickly than steel, for example, at least when using copper sulfate as electrolyte. Ideally I would have etched these with ferrous sulfate, but my local hardware store doesn’t carry that stuff. 
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A quick self-portrait; a friend took the original photo that I worked from. Hand drawn and inked, then scanned and digitally coloured.
Apparently I stand like a Scandinavian Noir detective…
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