In the final part of the series, we fix the timing issues with the code, add an NPN transistor to drive the output relay from a 5V supply an...
In the final part of the series, we fix the timing issues with the code, add an NPN transistor to drive the output relay from a 5V supply and add a thermistor for temperature monitoring. We assemble all of the components into the 3D-printed case and then set to work on designing a suitable welding head. Finally, we weld together a battery pack at 5x speed so you can see how well it all works.nnThe music used during the pack welding part of this video was a collaboration between myself and a friend. I'm afraid I can't tell you what it's called because we never named it, and you can't buy it anywhere either... Sorry.nnThis project is released under the Creative Commons Attribution Share Alike License.nnMessing around with mains electricity is dangerous business and there are risks of death by electrocution and fire. nThis series of videos is intended to show you what I did - not to be a defacto guide on the best way to do things. nIf you decide to undertake your own similar project, I accept no responsibility or liability for anything bad that happens to you.nDo not even think about replicating this project unless you are fully competent in all areas covered and fully understand exactly what you're doing and the risks involved.nThere is also an element of danger in welding to batteries, so once again, if you decide to do that, you're doing it entirely at your own risk. If you melt holes in your batteries and they burst into flames, then it's not my fault.nnWith all of the caveats above, I'd love to see someone else make one the same, or even better make an improved version and contribute back code tweaks or 3D design improvements. nFor changes to the code, please raise a pull-request on github. nTo collaborate on the 3D-model, you'll need to message me with a Fusion 360 username so that I can give you edit permissions.nnHere's the relevant links:nnThe LUA Code: https://github.com/jimconner/NodeMCU-Dual-Pulse-Weld-TimernHere are the STL shape files for 3D-Printing: https://www.youmagine.com/designs/battery-tab-spot-welder-projectnhttps://www.thingiverse.com/thing:2429361nThe Autodesk Fusion 360 model: http://a360.co/2sEro9YnnWhere to get components:nnI chose the components for this project almost entirely on the basis that they were lying around on my desk, or not tidied away correctly into component trays. nI only actually ordered two parts specifically for this project (the illuminated power switch and the 35mm crimp terminals.), but as I was asked to provide ebay links, here's some now:nnThe OLED Display : ebay search for 'arduino oled blue yellow i2c'. Sort by lowest price+p&p. Choose the cheapest one which has 4-pin connector (you don't want the 7-pin SPI version)nThe Solid State Relay: ebay search for 'solid state relay 40A'. Choose the cheapest one. Fotek brand (I'm told that they're fakes/clones, but they still work OK)nThe Power Swtich: ebay search for 'Mains Snap-In Illuminated Rocker Switch 15A 250V'. They are a standard size to fit a 22x28mm coutout. nNickel strips for welding: ebay search for 'nickel strips battery 100pcs'nCopper bar: ebay search for 'flat copper bar 15mm x 3mm'nCopper rod: ebay search for '3mm copper rod'nNodeMCU board: ebay search for 'NodeMCU LUA'nRotary encoder: ebay search for 'Arduino rotary encoder'. They all look the same to me.nThermistor: ebay search for 'TTF 103'nThermal Cut-out swtich: ebay search for 'Thermostat Temperature Thermal Control Switch 20°C~150°C'. I used a 45C version because PLA softens at 60C Less
