Hi everyone ,
In this instructable, i am gonna share with you how i made these simple key chain USB power supplies that gives separate outputs from 1 to 5 V DC.
These can be used for bread board experiments that need low voltage dc supplies.
Step 1: Collect the Raw Materials Needed.
This simple project needs a few things.
- Copper clad board.
- Old key chain.
- AS 1117 voltage regulator (3.3 V).
- 100 Ohms resistors (SMD).
- Stacking header pins (male).
Step 2: The Circuit...
We are gonna make two key chain power supplies.
One gives 1 to 5 VDC output and the other gives 5 and 3.3 vDC output.
The first one "circuit 1" is nothing but a voltage divider network connected between the +5 and Gnd terminals of the USB output.The voltage divider is designed using five 100 Ohms resistances in series so that each one can have 1 Volt across it. SO, if we need 2 V, then take output across any two of the series resistors. And so we may take 1,2,3,4 and 5 V DC output.
The second circuit, "circuit 2" gives two voltage outputs, 5 and 3.3 V DC. We use AS 1117 smd 3.3 v voltage regulator in this circuit.
Step 3: Make the Circuit.
- Cut the two pieces of copper clad board as per the picture and to fit the usb port (in the shape of a pen drive).
- Draw the layout diagram of the circuits on the board (as per the circuit diagram).
- Carry out the etching using ferric chloride.
Step 4: Solder the Components.
- Solder the smd components carefully.
- Solder the connectors.
Step 5: We Made It :)
- glue a small piece of pcb at the end to make the thickness enough to fit the usb port.
- drill hole to connect the key chain.
- put everything together.