Fighting with computers

3D printers use a heated bed to promote the adhesion of molten filament to it. Many printers have a heater and a thermistor to heat up and measure the bed temperature. Some microcontroller code creates a closed-loop regulator that keeps the bed temperature around the desired set point. The question is what to do when you have a large bed. Some manufacturers have just gone bigger: a large bed is coupled with a large heater and a thermistor (or thermocouple is used for measuring the actual temperature of the bed). Others, like the Prusa XL print bed, have actually gone smaller and composed the larger bed as a set of smaller tiles, each with an independent temperature control. That approach is more complex and expensive in terms of control. Still, it comes with the added advantage of independent control of the temperatures of different bed zones, which might have power savings consequences. From where I stand, simpler and cheaper is the way to go with our project's budget. So, I settl

 For one of my recent projects, we built a pellet-extruder 3D printer. Its hotend has four different temperature sections. That means four heaters and four thermistors to create four independent temperature control loops. So far, all my printers have had a single heater for the hotend, so this was new to me.  Handling so many temperatures required enough thermistor inputs on the control board. In my case, a Duet 3 6HC board features precisely four temperature inputs. Which seems to be enough. However, I have a heated bed (which I will describe in an upcoming post) that also needs its temperature to be monitored, so I need five temperature inputs; I am one short so far. The solution was to buy an additional Duet Expansion 1HCL board. This one features two additional temperature inputs, two additional fan outputs, and an additional high-power motor driver I will not use now. This additional board connects to the 6HC using a CAN bus interface. Its default address is 123; you can test it w

  So you have a 3D printer, and you want to configure your slicer so it can create g-code for it. The most obvious data is the size of your print envelope, but a less visited problem is how to deal with pellet printers or past-based extruders. Your printer for sure can respond to your commands, so after a while, you have a good understanding of how the amount of material needed to get your desired line width at a given layer height. That ratio would be the number of steps/mm the extruder needs to print the sort of lines that you need. Now you just need to tell your favorite slicer that. If you are like me, and your favorite slicer is PrusaSlicer, please be warned that a 1200 mm cube is its maximum print envelope (that was a no-go for one of my concrete printers).  On the other hand, Cura was happy with a larger volume (but I have not asked or tested their max volume). However, I was expecting the "filament diameter" in the extruder configuration in Cura to be the number I cou

  Given that my previous cellphone renovation was a switch from Android to iPhone, I did not expect it to go smoothly, and it did not, primarily because of the WhatsApp database export. But this time, moving from one iPhone to a newer iPhone, I expected a smooth transition. The process started nicely; the new iPhone guided me through a process to find the old one and begin transferring data. However, at a given point, I was left with the latest iPhone stuck in the process (with a non-working link that prevented the import from finishing). To make things worse, the old iPhone was asking me if it was ok to delete all data and restore it to factory defaults (which I did not want to do before I was sure all my data was safely transferred and all my apps were working correctly on the new iPhone). I could only think that calling Apple was the only choice, and I am glad I did, as they helped me sort this out. However, all that ruins the experience of a smooth transition. Even worse, they reco