Automatic Showerhead Light: For over a year now, I’ve been a staunch supporter of the LV version of the Pololu mini pushbutton power switch (2808). This module serves as an electronic power switch, enabling the control of any device’s on/off state through the mini push button on the board or an external on/off or control signal. Remarkably, it can handle voltage ranges from 2.2 to 20 V, with a capacity of up to 6 A, making it exceptionally versatile and applicable to a wide array of projects.
Here, I’ll introduce an unconventional yet intriguing project that harnesses the Pololu 2808 switch to create a portable and expandable showerhead light. Traditional showerhead lights emit a gradient of colors while water is flowing, but my aim is to design a compact LED light that serves as an additional light source above the showerhead, especially in dimly lit bathrooms.
As depicted in the image below, it’s a straightforward endeavor to craft a showerhead light by modifying a generic clip-on gooseneck LED light. In addition to the Pololu module, the essentials include a high-power white LED and a suitable battery pack.
- Toshiba ER6V/3.6-V Lithium Battery (3.6 V/2,000 mAh) – 1
- White 3-W High-Power LED (3.2–4.0 V/700 mA) – 1
- Pololu Mini Pushbutton Power Switch (2808) – 1
- Lithium Battery Wall Charger (3.6 V) – 1
The initial circuit prototype was assembled on a perforated stripboard. However, it is advisable to integrate the circuit within an enclosure, such as a disused clip-on light, which conveniently accommodates the charger input socket (J1) and the additional push switch (S1).
The placement of the socket and switch can be chosen based on your preference. The onboard pushbutton on the Pololu 2808 or an external pushbutton can be used to control the activation and deactivation of the white light. Additionally, you have the option to attach a “water sensor loop” to the switch interface JP1. Two exposed wire loops are positioned just below the showerhead (refer to the next illustration), so that when water makes contact with the wires, it closes the switch connection, activating the white light source.
It’s worth noting that the control input exhibited surprising effectiveness even with a small current passing through a splash of water from the showerhead. Indeed, tap water’s conductivity is sufficient to trigger the Pololu switch!
Please note that the Pololu 2808 switch has several drawbacks when compared to mechanical switches. So be sure that you fully understand this product before using it in your project (https://www.pololu.com/product/2808).
An old (discontinued) version of a near-same low-voltage Pololu pushbutton power switch. (http://www.pololu.com/catalog/product/751) is still available in India for under $10 from here: http://www.rhydolabz.com/robotics-robotic-parts/