Valentine Heart Pendant with LED

thingiverse

This is a small heart pendant for Valentine's Day, with a flashing LED and battery for extra interest factor. It's perfect as a gift or personal fashion item. No soldering is required -- just 3D print, insert an LED, and CR927 battery, and assemble (see the pictures in Post-Printing for details; note that strong finger pressure will be needed to press the lid on, but it will fit and stay in place). There are two variations of the design: "v1" has the strongest and most secure chain loop but won't lay as flat as v2. "V2" puts the loop on the structural lid for the best balance and flat appearance, but has a small risk that the body of the pendant could release and fall off. This piece is designed specifically for a 5 mm LED size, especially the multi-color flashing variety (both for extra interest factor and reduced current draw on the battery). These can be acquired from various electronics sources including Amazon (search for "Multi color Flashing LED Electronics 5mm"). The CR927 battery is one of the smallest 3V lithium cells available; they will last more than 12 hours in this design and are what makes the small pendant size possible. They also can be acquired from Amazon (search for "CR927 Lithium 3V 3 Volt Coin Cell Batteries"). Altogether, the electronics should cost less than $1 per heart -- and in bulk, less than $0.50. When the LED stops flashing it means the battery is spent; just replace the battery when you want to activate the pendant again. *** Update: I've seen more than 48 hours life from one CR927 battery in this design. Print Settings Printer: PolyPrinter 229 Rafts: No Supports: No Resolution: 0.20 mm Infill: 20% Notes: The bottom surfaces of the printed objects are what will be visible, so make sure the print platform is clean and ready to print a good bottom surface. The designs are optimized for a resolution of 0.20 mm, but anything in the range of 0.15 to 0.25 mm will work fine. Post-Printing Route the long (positive) lead of the LED into the bottom of the battery cup, and press the lead down as flat as possible. Either bend the lead so that it stays fully in the bottom of the cup, or cut off excess lead length. Place the CR 927 battery into the battery well with the + (positive) side down, and press down on the battery with light force to flatten the LED lead in the bottom of the well. Bend the shorter (negative) lead of the LED to cover the top of the CR 927 battery, as shown. Cut off any excess length of the lead. Make sure the two LED leads do not touch (they will be close, but there should be a small gap and they won't move after the heart back is installed). The LED should light when you press down on this lead; if not, you may have a bad battery or a short between the two leads.