My DIY projects out there for the curious souls to see.

    A couple months ago I finished my third homemade 3D printer. The objective was to make it as cheap as possible by avoiding all unnecessary expenses. In the end the printer came out well under 100€, with almost enough to spare for a 1kg spool of PLA.     One of the cost cuts was to omit a heated bed and instead use a piece of regular window glass as the bed surface. With the help of a heatgun the temperature of the bed could be brought up before a print and most of the time that would be enough to keep the part stuck to the bed.     The problem with heating the bed this way is that it's hard to keep the heat uniform and all the hot air coming from the heatgun also interferes with the hotend and causes instability so it was not ideal.  Nevertheless I continued printing this way because it already worked well enough for the small prints I was making.      Not long after completing the printer I overheated the piece of glass and caused i...

      I needed some MOSFETs for a four channel constant current load but didn't have any besides some counterfeit IRL3803 MOSFETs I had received from aliexpress. I mean these are still MOSFETs inside, just very small ones. For my load I need something that can handle 1A and max ~5W dissipation, so let's take a look at the silicon die and see whether these will work or not. The method described is only good for a rough estimate, but at least allows you to make use of the MOSFETs instead of tossing them away.     First I need to crack one open, which I already did when filing a refund, so that's done. I also need a genuine MOSFET as reference, that we'll use to extrapolate the approximate characteristics of the counterfeit MOSFET. For this I chose a blown NTD70N03R.  I used this website to take the measurements: https://eleif.net/photo_measure.html     The area on the fake IRL3803 die is abut 1.45sqmm and the area on the NTD70N03R is about 6.6sqmm, ...

      I got a defective Airwheels pack from my internship and it had 64 18650 cells inside, of which 16 were dead but the remainig 48 were still good. And I saw this as a great opportunity to make a big lithium battery pack for other projects, like my homemade electric scooter, for example.     These packs are most often welded together with spot welders but I don't have one. Previously I used to solder to salvaged batteries. When I salvage batteries I leave a piece of the nickel strip on them so that I can solder to it later. But for a big pack soldering would take ages, not to mention how tedious it would be trying to get a good solder joint without cooking the cell. Oh and don't forget the mountain of solder it would take and all the fumes you would be huffing the entire time. Because of this I decided that it's finally time to build myself a battery tab spot welder.     I've previously explored the world of spot welders many years ago and even expe...

      I've been making printed circuit boards at home for more than 10 years now and I've come a long way since the early days. Now I've reached the point where I can get reliable traces down to 0.2mm and perhaps even smaller but I haven't had the need for traces smaller than 0.2mm. And I've decided to share my knowledge with the world because I think this should help people get right into toner transfer with minimal fuss. So here it goes.     First you need a laser printer, because they print with toner and without toner there would be no toner transfer. For my toner transfer I use an old Samsung SCX-4216F printer that I found at the dumpster. It has a copier at the top and that's a very bad thing if you have younger siblings because they will stick anything they can find in there to make a copy. My younger brothers did this and in the process managed to damage the drum on the toner cartridge and it's very important to have it intact, because as it rolls ov...