Posts

Testing the ESP32-C3 ...

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  Having used the ESP32 using both Arduino IDE and MicroPython, I have been quite happy with it. However, I have found MicroPython more stable and powerful, especially if multithreading is needed. Do not get me wrong, you can get multiple tasks in FreeRT too, but it gets tricky quickly.  ESP32 features a dual-core 240 MHz Xtensa 32-bit processor, but the ESP32-C3 changes that to a single-core 160 MHz RISC-V processor. They both keep the handy Wifi and Bluetooth interfaces and a nice collection of built-in peripherals and communication interfaces (SPI, I2C, I2S).  What I did not know was the new architecture was also supported by Micropython , which was a nice surprise. So I went on and bought one of them to give it a go. The system feels a bit less powerful than its dual-core sibling but it works nicely with Micropython nonetheless. Having fewer I/O pins available can be a problem for certain applications but I definitely recommend this device if you need a wifi-enabled microcontrol

Crimpers, crimpers, crimpers, ...

 I happen to have bought a few crimpers over the years. I understand how convenient is to have a trusty connection using a crimper, but I have had trouble shelling out the hefty sum a brand-new required. Being mostly a hobbyist I had a difficult time accepting paying hundreds of dollars for a glorified set of pliers that I would use to make less than fifty contacts a year.  However, whenever I have had a hint that an affordable tool could do a reasonable job within a budget I have bought a new crimper. Most of the time to get a disappointing result, or a poor one at best. I usually deal with 2.54 mm DuPont and Molex connectors so I have bought SN-28B (actually twice by mistake), TU-190-8, and another one I bought from RS. The one from RS almost did the trick for DuPont but it crushed the top metal too flat so I needed to use some pliers so I could squeeze it into the plastic part. The two jaws did leave a small space on the side so I reckon the crimp was good but the geometry was off. 

The trusty ImageMagick package

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  Seven years ago I made a simple script to turn a pile of scanned exams into a personalized email for each student to get their marked exams. I used our photocopy machine that doubles as a scanner to create a large PDF file containing all the exams. ImageMagick's convert, identify and mogrify commands were used within the script for several massaging of the scanned pages but, years later, using WSL instead of a Linux machine, I was shown a weird error. None of the commands seemed to be able to handle a PDF file as a source anymore: identify-im6.q16: attempt to perform an operation not allowed by the security policy `PDF' @ error/constitute.c/IsCoderAuthorized/408. Luckily, I quick search lead me to a solution: just edit /etc/ImageMagick-6/policy.xml and enable PDF use, which was disabled as a safety feature as PDF can be an attack vector. More info .

Remote development of a hardware device

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I am familiar with helping other people remotely using tools like TeamViewer. Many times it has to do with a friend having trouble with her computer, operating system, or software.  But quite recently, I took care of the development of a complete machine without ever touching it even once. The project was part of a friend's Ph.D. work about the proper tensioning of old paintings. He asked me for help with a specific need in mind. He needed a machine that could push a probe against a canvas surface while monitoring the back force generated.  As usual, there were a few more constraints, like it was needed to be used in a few weeks as an appointment was already made with an important European museum. And all the parts needed have to be available online to get quickly to my friend's residence in Rome. Fortunately, my friend can solder and wire or build a contraption, though he cannot code. So the plan was to make this happen by shipping all the parts to his apartment and he will do

What is IDEX 3D printing all about?

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  While single extruder performance with BCN3D Epsilon W50 was not fast (around 20% slower than a Prusa MK3) its printing volume is significantly larger. So we put that to some u se, packing several large parts into the print bed.  If some of these parts are similar (either equal or mirrored) the use of IDEX can help here. So what is IDEX? IDEX is the acronym of independent dual extruders, which may not explain much yet.  These are 3d printers that have two print heads instead of one. Each one of these two print heads has its own extruder that can be operated independently from the other. This is quite a different thing than these other printers that can handle different filaments in the sense that here two extruders can operate at the same time, so two hotends can be pushing plastic onto the bed to create two different parts. Not very different as if you were able to write or draw with a pen on each one of your hands, but with a little catch here: although we can draw two lines at th

When epsilon is actually quite large ...

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Before the summer holidays, we were approached by a Spanish company ( Sicnova )  that wanted to help us with our research project about modular 3D printed beams . So after some talks, we borrowed a brand new BCN3D Epsilon W50 3D printer.  Contrary to other printers and similar to an industrial robot, the machine was delivered over a wooden pallet that needed a manual forklift to move it to our lab. Overall volume was not very different from a washing machine or dishwasher. I went to the lab for unpacking it but returned empty-handed: the instructions called for two people for the unboxing procedure. So I had to return the next day with a colleague so we could remove the packaging and rise the printer to the workbench where it will live. Once the printer was powered on, we noticed the nice touch-sensitive display on the bottom-right corner, that greeted us and guide us through the setup procedure.  The printer has a USB, Ethernet, and WiFi connectivity, but we were not prepared to netw

What happened to Meshlabserver?

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A few days ago, one reader comment on the blog (thank you Lance) made me aware of the changes happening with the Meshlabserver program. I misread the comment first as if the MeshLab project was discontinued, and after checking I replied back that a new released was just a few days old. But then it hit me, Lance was spot on,  MeshLab  project was deprecating the Meshlabserver program, now becoming "unsupported" and users were diverted to a new program called  PyMeshLab  which, as you all can guess, is now Python-based.   So that was interesting news for me as I have been using meshlabserver for various automation processes dealing with 3D meshes. And the even better news is that now installing it should be quite simple, just type pip3 install pymeshlab.  Linux and OSX install was uneventful and it all worked as expected. I learned that you could even use .mlx files created with Meshlab software. Windows 10 install was equally simple but, once I imported the library in Python I