June 18, 2023
Description
Small rechargeable lamp with timer using the battery recycled from an electronic cigarette. Challenging project because of the small SMD components.
Parts : please see photos. For glue use two component glue AB glue (Aliexpress).
How to build : Print the 3D parts. Attach wires (use 0.2-0.25mm enamel isolated wire) to the micro USB socket, the LED and the battery.
Glue the LED, the reflector and the 3D printed tube extension together.
Solder the 1N4148 diode 12 ohm to the USB and push it in the space above the USB socket, glue the assembly in the 3D printed plug too. Glue the switch.
After the glue hardens, solder the AO3400 (2N7002) 10uF (ceramic) 10Mohm parallel on the switch.
Connect all this together and check the light and the charge. The LED should be on for 20-30 seconds and go out when the 10uF discharges via the 10Mohm and the NMOS switch goes off. The charge can be checked by measuring the charge current (about 40mA) or the voltage drop on the 12 ohm (0.1-0.5V).
The tube: cut the original 16mm dia steel tube in half (44mm) with a Dremel.
License:
Creative Commons - Attribution
akosboda
