All the pictures after the zoom image are larger pictures of the steps, take a look if you need to see the details.
Step 1: Step 1 - What You Will Need.
- 2 Small plastic bottles.
- 2 Medium plastic bottles.
- 16 Screws.
- 2 X 6.5cm long - 20mm diameter PVC pipe.
- 2 X 6.5cm long - 25mm diameter PVC pipe.
- Double layer fiber glass PCB
- 2 Springs (Made of a weldable metal)
- 2 Normally open push buttons
- 5 Green LEDs
- 5 Red LEDs
- Cable with 4 wires
- 2 NPN Low power transistors (I used BC337)
- 2 X 330ohms resistors
- 2 X 10Kohms resistors
- 9V Battery and clip
Soldering iron, scissors, screw driver, saw, tape, glue gun.
Step 2: Base
Step 3: Switch
Step 4: Top
Orange - Green LEDs positive terminal.
White - Green LEDs negative terminal.
Green - Switch Terminal A.
Blue - Switch Terminal B.
Step 5: Circuit
Step 6: Wiring
Before soldering the circuit let's do the connections and test the device.
Now, that the emitters are connected i'm going to label the transistor marked by the green arrow as green transistor and the red arrow as red transistor.(The same for the switches)
Step 7: Twist, Solder, Tape
If you can't find the base, just turn on the circuit touch the battery "+" terminal with one finger, and when you touch the transistor base, the LEDs will show a weak bright. Do it with the two terminal you labeled as switch, one of the them must be the base.
Step 8: Play
Step 9: Appendix - Expanding the Circuit.
When S1 is pressed, Q1 is polarized and the current flows through D1(LED1). If S2 is pressed now, there won't be enough current to polarize Q2, because the current is being drained by Q1 and D1(LED1).
That's why only one LED can be turned on, one disables the other.
To add another set of lights, every single switch would have to disable the other two. See figure 2.
In the second circuit, pressing one switch, two LEDs will turn on, and nothing changes if the other switches are pressed.So the output would be:
Press: - Lights ON:
S1 - 1,2
S2 - 1,3
S3 - 2,3
I'm not sure if it's the best way of doing it, because it would later need decoding with AND gates.
If someone got a better idea please comment.
PS: Please rate this instructable if you like it. Thanks