Meetup report: 22 November 2018

Yes, these are just dry reports of what happened, but they provide a kind of archive of the goings-on at the Thursday evenings and gives me a way to track attendance and what’s happening.

I found a pic of the rendering of the vase, so here it is:

Scorped vase

Last week:

Steph got some 2mm Depron from a local hobby shop, and we talked a while about the ideal material and setup.

Kolijn continued with the design for the Lora signal strength tracker, and we went through options for getting the cases machined consistently. The plastic box is about R12, but would cost over R100 to get the holes in.

Danie came to chat about his art car project for AfrikaBurn. We tried to figure out how many controllers he’d need and how much power it would require. Lots.

Kim popped in for a short while to say hi.

This week:

Last Saturday and Sunday I messed around with getting a LED to sense light levels, and then average that out and get a moving envelope of the variations, so that I can communicate with an Arduino using flashing lights. This is still in a very early stage, but I can now reliably detect a flashing light at about 1Hz frequency, so it’s going to work. Thursday evening I found out that the capacitance (or something) of my hand approaching the board also has a big influence on the voltage levels, so we might be able to do something with that too.

SOS in Morse code, detected via LED

The MaslowCNC frame is built! Jan got the belts this week, and came to pick up my spare wood to be used for the build. The machine is to be housed against Otto’s garage wall, so I could not help build.

Maslow CNC frame up on the wall, no moving parts yet.

Steph had a four-character 7-segment display, and got it to display a scrolling ‘Hello’ by putting together pieces of code found from various examples on the web. Pretty awesome!

ello, because 4 segments

Reuben had the new trinamic drivers with SPI control installed, and spent some time getting the Marlin settings right. In the end, the motors did not run. Time to take a step back and get it running using the non-SPI setup, then we can sort out if it’s a setup problem or a hardware issue.

Reuben getting the settings figured out

Altogether, a really nice evening.

Meetup report: 8 November 2018

Last week:

I finally figured out a good rendering setting for my random-scorped vase so that it takes less than forever to produce a rendered stl file. I started heating up the printer, but then got busy discussing things.

Steph got a few mini drone boards from a friend. He wasn’t sure what condition they were in, apart from the motors being gone. He managed to solder some leads to the power input, and the board lit up. Progress!

Kolijn (first time visitor) worked a bit on a Lora board that was developed together with JP Meijers. This board transmits GPS location on a regular basis. If any TTN (The Things Network) access points pick up the transmissions, they store that in the cloud together with some signal strength stats etc. This then allows them to produce a coverage map of TTN coverage.

He was looking at light pipes to mount in the standard bought case, instead of having to wire up external LEDs. Looks like a good solution. The switch is still a problem, since they want something recessed that cannot be accidentally switched off.

Kim visited, and we talked through a few options for her silicone bioreactor stretching setup. The basic setup would involve having a silicone part with some Tyvek sheets molded in on each side. This would then be attached to an 8mm shaft that turns to give the stretch. An 8mm shaft gives about 24mm of movement per full rotation, and there will be one on each side. Even if rotation is limited to half a rotation, that provides about 24 mm of stretch, which is more than the 10% needed on a 100mm silicone surface.

This week:

The vase got printed! Due to the low-poly render, the edges are quite sharp, so there is a lot of ghosting on the surfaces. Not great, but at least it works.

I also started with a project to print parts containers, like little parts bins that I can arrange on a grid. Single wall for this is not great, and my printer seems to have a few problems with the bottom 5mm of the prints, so this was not a huge success. Yet.

Steph brought along a cardboard plane that he wants to put radio control onto. It might be too heavy for the motors he has, so we discussed some alternative materials and design. We went into propeller selection and gearing as well.

Kolijn worked on the layout for the TTN GPS board and chatted a bit about how it works with Jan, who helped set up the hi-sites for this and had some ideas around power saving for the GPS module.

The motors and motor drivers for the MaslowCNC arrived! Jan and Otto got the motors turning with PWM and reading the encoders. At the end of the evening, they got the motors to run 5000 encoder steps and then reverse for 5000 steps, so we now have some confidence that it all works together.

We also spent some time discussing the layout of the frame for the MaslowCNC, taking into account that we want to cut right to the edges of a 4X8 foot board.