Fighting with computers

Since I got a beta version of Hephestos 2 from BQ before its launch, I have been using that printer more and more. After the initial annoyance about doing things on a certain way (like heating the extruder before performing a home move on an axis) I have got used to these details and I do not care anymore. And with a few exceptions were a part bottom failed to stick to the bed (nothing that a bit of hairspray could not fix) the printer has been delivering consistently quality prints. Z-axis became a bit noisy on long moves but I have no other complaints. However,  all the time I have been using PLA or Filaflex on a cold bed. There is no provision for a heated bed add-on so I had a look around for a stand-alone temperature controller.  I have found a simple pcb unit with display that controls a relay for a heating load up to 20A. Not sure how long that relay could last but for less than $5 I am going to give it a try. Next the bed, I do like aluminium beds with power resisto

I am working on an Art project that requires some radio-reception capability on a Raspberry Pi. I available online . But given the local nature of the data I need to treat this time I have to use a local receiver. have used in the past some interesting website that feature an SDR device whose reception is One suitable device I found very inexpensive are DVB-T USB dongles originally intended for watching Digital TV on a computer. These dongles can be had for less than $10 on eBay. The good thing is that the chipsets employed are Linux supported and there is a bunch of useful software that can use them as a Software Defined Radio (SDR). What is SDR? Well, basically it can act as a multipurpose radio scanner for many different purposes as spectrum usage recorder, amateur radio receiver or just listening to FM radio or airplane ADS-B transponders. For that latter purpose there is a cool program called dump1090 that will receive and decode the messages of the airplanes' tra

After watching a video of a new pen plotter made by Evil Mad Scientist we wanted to have a similar device. And having a 3D printer at hand plus some CAD software like Onshape or Fusion 360 it was a good exercise to design the whole thing. As usual the process was not completely straightforward, as initially it was more about copying the model we saw but as things were coming together some new ideas were explored. So while the first mock-up was based entirely on laser-cut parts (some of them glued together to make them thicker as the crappy laser I have access to is really depth limited as it is low-power).  Why laser-cut? Well because it was faster (or so it was supposed, but don't get me started on that). Once the first model was put together several ideas pop up: First, motors are in the way of carriage motion and reduce a bit carriage travel along smooth rods. Second, motors require another part that could be fused with the machine feet and rods support. Third, t