Johan Beyers

Using Pocket

Sun, 20 Oct 2024 00:00:00 +0000

I’ve been using Pocket for more than 10 years, and I find it indispensable. It’s simple and fits easily into the way I handle links.

Using pyenv for easy environments

Sat, 21 May 2022 14:40:18 +0200

This setup works really well to manage Python virtual environments when working over many projects.

Calibrating wall ooze on a 3d printer

Sun, 30 May 2021 00:00:00 +0000

This is part one of a set of calibration test prints to fine-tune your 3d printer to print accurate 3d components to a level where the components will fit each other without post-processing.

Most 3d printers overshoot their wall widths while printing, making components just slightly too big to really fit each other.

Meetup 2019-05-02

Fri, 03 May 2019 00:00:00 +0000

Threads and Batteries: Another nice evening, with a full garage! Some highlights: Steph had his power-assist glove finished, and demoed it. His sensors on the fingers are just bare wires and the Arduino senses the capacitance/resistance. Nice solution, and a really neat project! He then worked on getting a radio link set up, blinking a LED triggered via the link. Hedley brought his roomba-knockoff vacuum cleaner and spent some time cutting out the battery compartment.

Meetup 2019-04-25

Sat, 27 Apr 2019 00:00:00 +0000

Skateboards and barcodes and CNC: That was a nice meetup! We had lots of people doing interesting stuff and sharing knowledge. Lowku and Chris worked further on their barcode recognition setup. Getting the Python dependencies and cv2 installed took a while, after which they started detecting barcodes of everything in the garage to test different materials and lighting conditions. Donnie brought his homemade CNC machine and we looked it over, including his plans for the next, larger version.

Meetup 2019-01-10

Fri, 11 Jan 2019 00:00:00 +0000

Wings and chairs and maps and cables: I decided towards the end of last year that the organising of the meetup was going on in too many disparate places: I advertised it on ZaTech Slack, Facebook, Twitter and we even had a Whatsapp group. I wanted to consolidate all of that. This is the first meetup organised through meetup.com, which is great for introducing the meetup to people in the area.

Meetup 2018-12-06

Mon, 10 Dec 2018 00:00:00 +0000

The last meetup of the year was quiet: Only Bouwer arrived, so we experimented on his project. Bouwer needed a circuit to buzz when pressure is applied to a sensor mounted on a stick, basically. He had some Velostat, which is a good choice in this case for building the sensor. The idea is to build a circuit with an op-amp set up as a comparator to then drive the output buzzer.

Meetup 2018-11-29

Fri, 30 Nov 2018 00:00:00 +0000

We had a very full garage this week! Lots of people, interesting projects, even though we had loadshedding from 8pm to 9pm. I did a few labels on my masking tape labeller, after having found a way to make it run consistently without first having to recompile the Arduino code. Steph cut out the wings for his pico stick (copied off my stick’s wings) and worked on his 7-segment display.

Meetup 2018-11-22

Sat, 24 Nov 2018 00:00:00 +0000

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

Meetup 2018-11-08

Fri, 09 Nov 2018 00:00:00 +0000

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.

Thursday meetups so far

Sat, 08 Sep 2018 00:00:00 +0000

The past 5 months I’ve held regular Thursday evening meetups in my garage. Some notes about things and trends I’ve noticed. Consistency counts My way of announcing this does not reach everyone interested, but since I’ve been doing this consistently every Thursday evening, people pitch up. I’ve only missed a few weeks while away on vacation in June/July. Make it easy It takes me about 20 minutes to transform my garage from car storage to makercave, and about 15 minutes to move it back again.

Meetup 2018-05-31

Fri, 01 Jun 2018 00:00:00 +0000

Knock sensors, ATTINY85, Satellite antennas, huge 3D printers and some drawing machine stuff. Last week First, a quick report on last week: Steph did the Arduino knock sensor tutorial, but it looked like his piezo element was not working. We tried a few of mine, but most were actually buzzers, which don’t work in this application. Evert came by: He’s interested in an IOT project with remote sensing, so we talked through the options, paying attention to the power requirements of the different technologies.

Meetup 2018-05-17

Mon, 21 May 2018 00:00:00 +0000

3D printers, robots and Sonoffs. My Sonoff Basic Wifi switches arrived! My evening was spent getting them working and set up the way I wanted. First step was to connect them and get them going with the stock firmware. I downloaded the EWeLink app and got one of them working. That done, they needed to be reflashed with OS firmware. Tasmota looked like the most complete firmware for the Sonoffs. It also had one BIG advantage: OTA (Over The Air) updating from the stock firmware to Tasmota!

Meetup 2018-05-10

Mon, 14 May 2018 00:00:00 +0000

Interesting evening, and we’ll do it again this Thursday. Earlier in the week, I managed to redesign the pendulum ball holders to snugly fit the magnets in place, as well as being a bit more springy an nicer-looking. My mission for the evening was to print out a few examples and tweak until happy. I did get a few prints, but the bottom layers are squished and misaligned, leading to a misshapen print that did not fit that great.

Meetup 2018-05-03

Mon, 07 May 2018 00:00:00 +0000

We had an interesting evening. My phone camera is fuzzy, and I forgot to take lots of photos again… Otto showed us his 3D printer battery holder for an ancient Festo drill/driver. Great design, with space for 4 18650 cells and a voltmeter to provide manual discharge cutoff. A really solid way to upcycle a rugged tool with modern batteries. No photos, aaargh. Otto also brought his Fluke scopemeter, and we hooked it up to the pendulum wave op-amp output and the FET gate.

Meetup 2018-04-19

Fri, 20 Apr 2018 00:00:00 +0000

Another successful maker evening! I was so busy that I forgot to take any photos, and I did not make a timelapse, so just a text report this week. Tom brought his little walking robot, an updated version of Bob The Biped . Very nice little robot. Stèph brought his Alphabot 2 robot, which he’s busy getting up and running. With some help from Tom, he managed to get it programmed, but there’s still some issues with the display etc, and he needs the correct batteries to get it to run.

Damping the swinging cutting wire in my vertical hot wire cutter

Sat, 14 Apr 2018 00:00:00 +0000

My 3D printer has a detachable x-y stage, which makes it very easy to create a hot wire cutter. In fact, that was the first thing I did when I got the x-y stage working. The cutter is very simple: I hang a rope from the roof, with the cutting wire (a steel guitar string) tied to it, and a 12V supply to heat up the guitar string. I added a weight at the bottom to keep the guitar string under tension and vertical.

Meetup 2018-04-12

Fri, 13 Apr 2018 00:00:00 +0000

Yesterday evening I hosted a Maker evening in my garage. We had some good discussions and even worked a bit on projects! The garage door was wide open most of the evening, so people had no trouble finding us. Nice warm evening. Timelapse of almost the whole thing here: https://youtu.be/rVXQBAnWsEs Discussions Otto showed his very nifty 3D printer that folds up into an aluminium tool briefcase. He mentioned how much trouble he had getting the heated bed to work, since it’s a very specific smaller size.

Having a meetup in my garage

Wed, 11 Apr 2018 00:00:00 +0000

I’ve decided to start holding makers meetups in my garage. I announced it on Facebook on the Arduino Cape Town group and on Zatech Slack. Here’s some info, copied from the announcement posts: Initial announcement: Calling all Makers in the Stellenbosch area! I have a double garage, a bunch of tools for mechanical and electronic making, and Thursday evenings dedicated to building interesting things. Bring your projects, get some help and inspiration, and make things!

Building a Speedometer for my Dog

Fri, 06 Oct 2017 00:00:00 +0000

I built a Persistence of Vision speed indicator for my dog, using an Arduino, a few LEDs and resistors, and less than 40 lines of code. This is the story of the process and results. The beginning I’ve had an arduino for ages, but didn’t really have a project that I wanted to build. Then, at the end of 2012, I had an idea: Why not build something interesting and a little bit crazy?

Impressions of Beijing

Wed, 22 Oct 2014 00:00:00 +0000

Our family went on a 10-day trip to Beijing at the beginning of October. I won’t give a blow-by-blow account, just note some of my impressions. We were invited by Astrid’s parents, and stayed with them. Her father is a guest professor at the Beijing Forestry University for a few months each year. While we did all the touristy things, we had a chance to experience some aspects of Beijing city life that the typical short-term tourist does not see.

A trick to autonumber in ZPT

Sun, 21 Sep 2014 00:00:00 +0000

I had an interesting issue a few months ago. I was doing some work where I needed to create a pdf from a template. This was a numbered legal document with optional clauses. The problem is this: How do you make some clauses conditional, but then autonumber the rest? Normally, you would hardcode clause numbers into the paragraphs, but if you did that, the paragraphs following on the optional ones would be incorrectly numbered.

Configuration tools: A few thoughts

Tue, 24 Sep 2013 00:00:00 +0000

I just found a post in my drafts folder, summing up my thoughts about CM (Configuration Management) tools from a little under a year ago. Since then, I’ve started using Ansible to set up servers. I’m still not fully converted, but I find Ansible a very useful tool. I have 7 active machines at home, and running my update scripts on each of those is a pain. Ansible makes it a lot easier.

Setting up a simple smtp server for testing

Sat, 26 Jan 2013 00:00:00 +0000

On many websites, there is a need for sending mail from the webserver. While testing, it’s sometimes painful to get a working smtp server to test this. I’ve used this script for a while now, since it’s the simplest way to get a mailserver running. It will accept any smtp connection and print the mail to the terminal where you started it from. The script: 1import smtpd, asyncore 2 3print 'Mailserver is on port 8025.

Plone Conference: A great experience

Sun, 21 Oct 2012 00:00:00 +0000

I went to the Plone Conf 2012 in October. This was my first Plone conference, although I’ve been working on Plone since 2006. The conference was from Wednesday 10 to Friday 12 October in Arnhem in the Netherlands. I also stayed for the coding sprint on the 13th and 14th. TL;DR: The conference was awesome. I had an incredible time, learned a lot and came back energised and enthusiastic about contributing to Plone and the community.

100 Words

Fri, 28 Sep 2012 00:00:00 +0000

100 words each day. That’s the goal. I have almost started a blog for a few years now. I get going with a post, and then the impetus to finish just kind of peters out. So I’ve decided to take another tack: Just write consistently each day. “We are what we repeatedly do. Excellence, then is not an act, but a habit.” - Aristotle Why 100? 100 words per day is a manageable goal.

Using Fabric to manage your deployments

Sun, 23 Sep 2012 00:00:00 +0000

I’m using Fabric very successfully to manage deployments of projects on my servers. Fabric is simple enough that it does not add extra layers of complexity to the setup, and easy enough to use that it makes deployments easy and much less error-prone. This blogpost is an updated and expanded version of a presentation that I did at the local Plone users group. What is Fabric? Fabric is a simple system to write commands that can be run on remote systems.

Polycaprolactone: Wonderful stuff

Thu, 23 Aug 2012 00:00:00 +0000

I recently got my hands on some polycaprolactone, and I’m really enjoying playing with it. It is one of the most useful materials I’ve seen in a long time. This is a summary of a talk I gave at #HackSTB on 21 August. So, what is it? Basically, it’s plastic that you can heat up to just over 60 degrees and hand-mould it into any shape you can think of. It sets as a white plastic that’s strong and tough.