Printer back online

After a long hiatus, my trusty printer is now back online. The hiatus has partly been due to a series of problems, partly due to me finally getting my shit together to do a proper workbench in my room (another post coming on that soon). Among other things, I replaced my Melzi with a new and slightly nicer one, though I'm not now sure that the old one was actually broken - turned out despite my testing the D-sub connection was done wrong. I was tempted to get one of the TronXY models which come with nicer connectors, as connecting raw wires in a cramped space is not easy and rather error-prone. I just don't know if they're truly compatible, and haven't been able to find any evidence one way or another. They seem to be Chinese knock-offs, and what I have seen about them doesn't sound encouraging, but then people only post when complaining, so I don't know.

After a number of rewirings - it seemed every time I fixed one wire another started having trouble - I now have it printing again, except the print fan is dead. That's not just a wire problem, I applied 12V straight to it, and it didn't react. So that needs to be replaced. It shows quite clearly on this McBenchy:

Ridges on the brow and drooping above the door - sign of a missing print fan

I have changed the hotend fan to take 12V from the hotend + on the breakout PCB. This is in preparation for putting in the probe, which should use the spare P pin as signal. However, I would need to put in either resistors or a voltage regulator to get the signal down to 5V, so I will probably need to redo the board to support that. Yes, I could make a tiny side board for this, but I have had it with messy setups. At the same time, I could change the connectors to some that are easier to plug in and out. This is the most informative thread on the current layout wrt probes. That thread says to not put too much current through the shared thermistor ground, this fan uses 150mA, which might be a problem for the thermistor, maybe. The probe wouldn't add much. If necessary, I could draw an X limit ground wire, but I would rather not. I think the lack of spare wires into the breakout board was somewhat of a false economy, it makes it hard to upgrade. There are also potentially good links on this thread.

Make Munich: Sensor chips, all-in-one printers, and some ideas

Make Munich is this weekend. I went out there for a couple of hours, that's all I was up for. It is better than last year, with more interesting little start-ups and creative groups rather than big commercial entities taking up chunks of space.  There were quite a few pretty retro things, as well as some really nice art pieces done with paper and lights:

Dragon!

I found a company called Aconno, which has done the small cheap battery-driven humidity/temperature/light sensor I've been thinking of for a while. At €30, it's quite a steal, and rather than having to be plugged in, it can do intermittent recording and use BLE for sending the measurements, leading to a lifetime of about 1 year with fairly regular logging, longer if you reduce the frequency. They have a nice app, open-sourced, so I don't have to worry about getting locked in. And the device itself can also be reprogrammed. Once they come out with some that do a bit more buffering and the price drops more, I'm going to get more - I already got two today.

I was also looking for something to potentially be my next printer, though no earlier than next year. There was a nice little 3-in-1 3D printer, CNC, and laser cutter called Snapmaker for €700 - smaller build volume than my Mendel90, but having my own laser cutter would rock.

One idea that crossed my mind was an easier way to make custom masks. Yes, it's possible to take a face mold and scan it, or scan straight from the face, but then turning that into a mask plus printing a curved surface nicely is not so easy. A simpler solution may be to print a generic (or possibly parameterized) mask flat using PLA, then heat it up to where it becomes bendable, and just slap it onto the face to shape it. Obviously, some face protection would be required, possibly foil, and some way to align it properly. A quick search doesn't show anyone having done such a thing. There's plenty of pages on making molds with 3D printing, or using 3D printing for various skin treatments, but so far little on hot-shaping PLA and only one page on doing it onto skin. There's this Reddit thread on hot-shaping which talks a bit about various people's experience with hot-shaping.

WARNING: Potential for burns ahead.  THIS HAS NOT BEEN TRIED!

I'm thinking laying the print flat on something pillow-like in the oven and heating it to its glass transition temperature (~60C). This allows pressing more evenly than if you press directly. Though maybe oven mittens for pressing would also work. Cut a piece of aluminium foil and two pieces of thick cloth, layering the foil between the cloths. Cut this sandwich to somewhat beyond the shape of the mask, with holes to put elastic band around the head to hold it in place. Then place the mask as symmetrically as possible and press.

Another less dangerous idea: 3D Julia sets. The 3D Julia sets are nice, but you can get some awesome structures out of 3D projections of 4D sets calculated on quaternions. And yes, people have done it, including a number of designs as vases, which is another thing I was thinking I would like to print.

I also want an illuminated hat. Not just a hat with an LED strip doing fun stuff, but where the light is more dispersed and just looks spooky.