EchoDot AA-Batteriecase

This is an AmazonEchocase with built-in batteryholder for 4 AA batteries, I know there are a few commercial available solutions to use an Amazaonechodot with a Li-battery but i wanted to be able to swap new batteries as soon as the old ones are empty. I use the echodot as a kind of internetradio when sitting outside so i didn´t want to have any cables, With four eneloop batteries this echodot will work for about 5 hours (moderate listening volume).
This is a remix from the batteryholder done by sleejmanj and combined with the case done by mariozwiers. Thank you bozh very much fr your great work! To build this you need additional parts:
1 switch (any switch will do, i used something i had lying around).
4 batterycontacts (https://www.amazon.de/gp/product/B00O9XV66Q/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1)
1 small step-up-usb-converter (500mA is sufficient) https://www.amazon.de/gp/product/B0762GR627/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1
1meter cable and a soldering iron.