I’ve replaced the head on the 3D printer. Mechanically, it’s all fine. Physically, it looks good. There’s a bit of wobble, but that’s a matter I can deal with trivially with shims.
Now I need to flash new firmware. Probably not using a .hex file – I should be able to expand the Arduino environment a bit. So listen out for sobbing.
The method I’ve chosen to find out where body heat is can’t be done at the price I want it. I’ve got the wrong phototransistors, or at least I’ve been told I have. I should put the two transistor test version together, and see if I can get any sensible reading, but it’s been hot and I’ve been busy and I’m a bad robot parent. I also need to tidy my room enough that I can solder in it. Even by my standards it’s been bad lately, as I’ve been working elsewhere. I’ve got borrowed kit here and there as well, which I need to move to my Place For Borrowed Kit. Maybe I’ll just fake a house fire and start again.
I’ve printed out a holder for a new hot end, and a new extruder, and I don’t have room on my table to set up a 3D printer or do any soldering. No matter how much I tidy my room, it ends up with no visible floor. Much of this is for other people’s projects, and some of that I’m getting paid for, but it’s still a drag.
Nevertheless, I put together a 3d printer extruder. Three times. Damnit.
Trying to use phototransistors to find heat sources and work out where they are, for the brief ‘my robot army will hunt you down’. They seem to be the wrong stuff for a human heat source. I have not yet tried this out, and I should, but I’ve been told they are wrong.
I can do some other stuff, like have an IR source in the middle of the pupil, and then bounce off that, which might work. However, for the moment I’m failing with a 3D printer instead.
I’ve got a few choices to make with Itchy right now. Do I want my own machine for making art, or do I want to make a set of machines that others can use? If I get this ready for kickstarting, it’s one path, if I make it into a better machine for me, it’s another. I really want to make the better machine, but at some point that will probably run out of money as a project. Things that I have to do for both are relatively limited in crossover, but the big one is a redesign of the head so I can put different tools on there. The pen holder and the lino cutter are two different set-ups, and I’ll want a servo for the brush pens, and so on. For me, I want to make the Y axis and the gantry far more rigid. If I make it for lots of people, I’d want to make the frame in MDF with steel rods. I guess I could convince myself I’m doing that to find out how rigid it is…
So, I’m starting with asking tech companies and art councils about funding. If that comes down to nothing, and I’m not getting enough commissions to let me do my own thing on it, I’ll streamline it for kickstarting in my spare time.
I’ve borrowed a roll of kapton tape (maybe kaptan, I don’t know, I just know that kaftan keeps on trying to get in the way) and I’m using that to keep the thermistor electrically isolated from the heating block. Now I’ll start ‘er up again…
The kapton stayed on, which is great. I need to bind the thermistor in better, which I’ll do when it’s all cooled down again, but nothing broke.
There’s a school of thought that says the hot end of a 3D printer shouldn’t be a solid block of plastic. After examination of both sides of the evidence, I have decided to subscribe to this.
I bought a cheap 3D printer. Once I had bought it, I found out it was from clearance but had probably already been in some way paid for, which is annoying. Someone else didn’t get their machine, and while I know there is no direct connection between me having this and another, particular person not having it, I am still profitting in the cheapness of a clearance machine from the money that someone else put in.
That aside, and it’s not a moral problem for me given the circumstances, I’ve now got a cheap 3D printer. The hot end, where the plastic gets melted, is famously terrible on this machine. It was a new design and tiny tolerances were needed, and it didn’t quite work. And also, I broke mine. So I’ve 3D printed a different big of plastic to hold a different head, and someone who was not using an old heater end and some other bits donated them, meaning I’m still getting a cheap 3D printer rather than an expensive time sink. It’s a cheap time sink instead. Currently bits of the hot end are cable tied together and the whole thing is about as shonky as a unicycle on a rocking chair.
Last night I put everything together. The tool chain is now clear. I learned what ‘tool chain’ means from Co-Squidly. It was a word I knew but had never really respected, and now I do. So, here’s the flow:
- Generate paths in Inkscape
- Inkscape -> Extensions -> GCodeTool -> Path to GCode
- Clean Gcode – inkscape uses
(comments like this) and gcode needs
;comments like this
- Import to bCNC (python GUI to send gCode)
- Send to Arduino
- Magic happens. Stuff moves!
The silver circle on the wood above was drawn in inkscape and sent to the machine where it was drawn with a Sharpie. I’ve built a machine. I declared tea and victory, and went home.
My friends have nicknamed it wobblebot. This is not unfair. It needs a lot of work, but it’s what I was after.
A few days ago I helped someone at makespace do some laser cutting. I saw a man looking at the laser cutter stock shelves, and he asked me about the stock and one thing led to another and once we managed to post bail, I explained that volunteers to buy stock and get their money back were what made Makespace run. So, he very kindly ordered what we needed as well as what he needed.
His name is Steven, and he’s a radio astronomer, and he was making the front of a clock. But, as he wasn’t yet trained on the laser cutter, he needed someone to do the standing there getting hypnotised by the moving red light. So I did that. He had the file ready, and I just plugged in the cutting speed and power, and pressed Start.
Red light travels least, as I recall dimly from some source or another, which may be why the lights here are red, or it might be that the red light has other properties in radio telescope land, like keeping night vision working, or it might just be that red lighting was cheap. But anyhow, this is now ‘at the Thorrowgood telescope at the Institute of Astronomy, helping astronomers find their stars’.
Sidereal time is to do with where the bit of the earth you are on is pointing, and nothing to do with whether you’re late for work.