LM2596 Case with Barrel Socket

thingiverse

Just a quick and dirty case for the LM2596. In my case, it's to step 12V down to 5V to power my ancient home CCTV unit. So, a few days before Christmas, I went out to my car only to discover that some thief had stolen the chrome dust caps from my car wheels! Thankfully, I don't fit expensive ones anymore because it's not the first time it's happened. But it was the first time it's happened when my car was outside my garage in full view of my CCTV. When I got back later on, I whipped out the CCTV's SD card to catch the thieves in the act. But Sod's Law prevailed: It turned out that the CCTV hadn't recorded anything since August! Arrrgh! Something in the CCTV's wall wart had died and left it putting out a very coarse 5.2V, 50Hz wave. So although the lights were all on, it was just acting as a flickering candle LED, and none of the processing side was powered for long enough to boot into record mode. I opened the wall wart to see if anything was obvious but there was nothing I could see; no signs of magic smoke or PCB skidmarks, not even a smell of overheating plastic to give me a clue. I then rummaged around in my shoebox of wall warts but I couldn't find anything that would give me 5V at the necessary current. I probably could have repurposed a USB charger but there were two problems with that: 1) I didn't have one, and 2) I didn't have one. But all was not lost. You see, while the CCTV box uses 5V, the cameras don't; they run from a 12v supply which is basically just a glorified laptop brick with barrel jacks. One of the barrel jacks was unused and I had an LM2596 converter and a spare barrel socket in my spares cache, just waiting to step into the breach. A few mouse clicks later I had a housing ready to print and once again the smell of molten plastic pervaded my living room. Once printed it didn't take long to solder the barrel socket and the lead from the old wall wart onto the board - although I won't claim it's my neatest ever soldering job; my eyesight is getting terrible for close work. It all works OK but I'll be honest, it's not an ideal solution. DC-DC converters are inherently noisy so you can see the effects of voltage ripple on the CCTV's monitor screen. But I can live with that for now because at least it's running again and the image is still plenty good enough to catch dust cap thieves should they ever return for another go. So I've just sharpened my bolt cutters in readiness and I hope it's still legal to castrate thieves if you catch them in the act! Happy Christmas, and a wonderful new year to all.