AC (E26 / A15) video light adapter for a softbox

thingiverse

This project is for people who has a home photo studio based on speedlites (portable flashes), Bowen style softboxes, and Godox S-Type Speedlite Brackets for Bowens (https://www.bhphotovideo.com/c/product/1342131-REG/godox_s_bracket_for_bowens.html). This 3D-printable adapter allows one with the above setup to easily swap speedlites inside their softboxes with AC (E26 / A15 base) LED bulbs, for video recording (youtube etc). **WARNING: this project involves dealing with AC 110V wiring, so do not attempt it unless you are comfortable with this stuff! Use insulation on all wire connections, and make it sure that AC voltage is not present on the enclosure bolts and nuts after you assemble the adapter (use a special AC voltage detector for that, like this one: https://www.amazon.ca/Non-Contact-Voltage-Tester-Flashlight-Buzzer/dp/B0819MDFYP). Never connect the adapter to AC when it is not fully assembled!** Important: to avoid a meltdown, only certain types of LED lamps can be used. If in doubt, test it with the adapter inside the softbox say for an hour, then measure the adapter/socket temperature with an IR thermometer. (BTW this is for video, so you wanna stay away from bulbs with a built-in fan.) For bulbs which are long and heavy (like the 100W bulb I describe below), one needs to add a small metal support inside the metal ring from the softbox (see the pics). I tested and found to be fully usable with my adapter the following two LED bulbs (both are 5000K): * 30W ( https://www.amazon.ca/gp/product/B09P5G6GNK ) . Very light (170g) and short, so no additional bulb support is needed. When using in a medium size softbox (65x95 cm), after one hour of use, the socket warmed up by a mere 6 degrees C. * 100W ( https://www.amazon.ca/gp/product/B089K9PX9S ). This bulb is much heavier (480g) and longer, so it does need a small metal support inside your softbox (see the pics). When used inside my large (1.5 m diameter) octagon softbox, after one hour of use the socket warmed up by 14 C (from ambient 22 C to 36 C), which is still perfectly acceptable, even if you use PLA to print the adapter. (PLA should be good up to 50 C or so.) **Warning**: the bulb itself gets very hot (around 80 C), so you have to use a glove when removing it! The light produced with this bulb+softbox combo is very even - I measured the brightness drop of only 0.6 stops when going from the center till the very edge of the softbox. This is much better than when using the same softbox with a speedlite. Now to the adapter. The model was created using Autodesk Fusion 360, and is fully parameteric - with a caveat: the model is so complex that when one changes the early parameters (like the diameter of the lamp socket), one has to fix some artifacts (like drilling the holes for bolts deeper, as they end up sealed on one side). I used the following non-printable parts for the adapter: * Atron Porcelain Socket With Leads (https://www.canadiantire.ca/en/pdp/atron-porcelain-socket-with-leads-6-in-0522844p.html). One might have to customize it slightly: in some units I had to unscrew the metal bracket, and re-bend it at a slightly different spot (1-2mm closer to the small hole), so the bracket protrudes a bit more from the porcelain base, which now makes it possible to use the Meccano metal plate (see below). I also used a shorter bolt, so it doesn't interfere with the metal plate. * Meccano metal plate with 1/2 inch distance between adjacent holes, 0.75mm thick, with 5 holes., or anything equivalent. * On/Off Boat Rocker Switch for 110/220V (https://www.amazon.ca/5Pcs-Rocker-Switch-Position-QTEATAK/dp/B07Y1GDRQG). * AC cord with a plug (I used the ones from my old TV cable boxes which no longer work). * Small stuff: a few M4 bolts/nuts/washers, one M3 bolt/nut. I first tried to print the adapter using ABS, but it warped too much (even though I use an enclosure), so the socket would not fit by a large margin. Then I switched to black PLA, which printed perfectly. (But with PLA you have to be more careful as it won't tolerate temperatures above 50 C.) I printed both parts with the face side down - that makes the interlocking parts match each other very well. I had to use supports for both parts. I printed with 0.2mm layers. ## The electric part * The white (neutral) wire from the AC cord connects directly to the white wire from the socket. * The black (hot) wire from the AC cord connects to the black wire from the socket via the switch.