You may or may not have seen in the news recently about a windstorm that left 200k homes in the Seattle Metro area without power. Well, mine was one of those households. To make matters worse - I was out of town that weekend and the tank was left unattended. Luckily I was able to get ahold of a friend who grabbed an emergency air bubbler and was able to get it in the tank and everyone survived. I don't want to be that guy again. While on the plane back, I came up with a simple design for a battery bubbler that automatically turns on the moment your power goes out. Basically the idea is when the power goes out, a relay closes and it turns on the air pump via a battery. While connected, the battery is charged by the USB-C power cable.
Parts List:
1 x 1.5V Emergency Air Bubbler
1 x Lithium Charger Module
1 x 1 Channel Relay Board
1 x DC-DC Buck Converter
1 x Parallel Configuration 18650 Battery Holder
2 x Lithium 18650 3.7V Battery
I built and tested it today and it works great! Just as intended, when the USB cord is unplugged, the air automatically starts. I was able to fit everything except for the battery in the original case. I made some notches for cables, and hot glued everything in place. I tested it a number of times and it works exactly as intended. When not connected and powered off, there is a bit of drain running the LED for the DC-DC converter. Right now, when the switch is off, it only disconnects the motors. The switch likely needs to be wired between the battery and the DC-DC converter to resolve. Until then, I will store with the batteries removed so they're not drained unintendedly.
Hopefully this is interesting and useful to folks.
Parts List:
1 x 1.5V Emergency Air Bubbler
1 x Lithium Charger Module
1 x 1 Channel Relay Board
1 x DC-DC Buck Converter
1 x Parallel Configuration 18650 Battery Holder
2 x Lithium 18650 3.7V Battery
I built and tested it today and it works great! Just as intended, when the USB cord is unplugged, the air automatically starts. I was able to fit everything except for the battery in the original case. I made some notches for cables, and hot glued everything in place. I tested it a number of times and it works exactly as intended. When not connected and powered off, there is a bit of drain running the LED for the DC-DC converter. Right now, when the switch is off, it only disconnects the motors. The switch likely needs to be wired between the battery and the DC-DC converter to resolve. Until then, I will store with the batteries removed so they're not drained unintendedly.
Hopefully this is interesting and useful to folks.