Building the USB reminder

Besides the kit you need 3 AG5 cells and a 3D printer to print some plastic parts

Here are the 3 stl files for the plastic parts
housing    bending help    fake usb plug   

You can buy the parts here

Prepare the housing part. Remove the support and file the opening until a USB plug fully fits

The usb plug must fully fit.

cut the leads of the microswitch.

Only leave some metal for the two outer contactss

prepare 5 pieces of lackered wire of about 25mm
Strip the ends of the wires by putting them in a drop of solder. Squeese the wire with the soldering iron and pull the wire out.

Make simple knot in the nylon wire and put it around the leaver of the micro switch

Put a drop of superglue on a sticky tape. Use a cocktail stick to put a little glue from the drop on the leaver-knot

Pull the nylon thrue the housing.

Put a USB stick in the housing and put the sitch in this position.

Pull the nylon thread so that the switch is closed. Wind the thread around the small square and secure it with a little super glue

solder 2 wires on the microswitch.

Put the switch back and push the wires to the hole next to the switch. Glue the solder side of the switch with hotmeld

Put some insulation around one side of the capacitor.

solder a wire on the capacitor.

bend the wires of the capacitor in the indicated way around the bending mold.

Solder a wire on the flex print. This flex pcb is used as programming switch.

Solder flex circuit on the capicitor. The wired side of the flex circuit should be around 0.5mm from the capicitor wire. This should only make contact if you push against the flex circuit.

Put the capacitor assembly in the housing. For additional reliability you can put a small piece of foam behind the coiled bend capacitor wire.

The cells must be oriented in theis way. Minus to the right.

Put the cells in the unit.

Solder the microcontroller to the piezo buzzer. You need to apply the minimal amount of heat to the inner contact of the piezo.
The piezo is connected to pins 2,3 and pins 4,5 .

The micro controller must be connected as in this schematic.

Solder one of the wires of the microswitch to the capcitor. All other wires must be soldered to the micro controller.

Put the micro controller in the cavity.

Glue the piezo buzzer on the housing. Piezo sound loudest if it is glueed air tight.

You can heat the piezo with a heat gun to melt the glue again and adjust the piezo.

Cut the stickers to the right side.

final product