Taking voltage/ stepping it up?

Hey fellas, i got soo many projects goin on ive been having a blast! My next project is a spirograph of course and here's what I'm wanting to do. Take 3v up to 6-9v. Can any1 send me in the right direction? Ive seen a tutorial on make where they wrounded wire to a transistor I believe... is there an smd component or to 220 component that does this?

Take 3v up to 6-9v.

Do you mean supply voltage or control voltage?

Supply voltage is a bit tricky and involves a switch mode boost circuit, these are tricky to keep stable and require a PCB, you are best gettng on ready made like the "minty booster"

If it is control voltage then it is easy. Arduino output through a 1K resistor into the base of an NPN transistor. Emitter to ground and collector to the higher voltage through a 1K resistor. Then the collector also goes to your higher voltage control circuit. Make sure you connect the arduino ground and higher power supply ground together.

Supply voltage is a bit tricky and involves a switch mode boost circuit, these are tricky to keep stable and require a PCB

If you can sacrifice a PWM pin and an ADC pin it may not be that hard to roll your own. Use the PWM pin to pulse the transistor and adjust frequency based on feedback from ADC sampling the output voltage. Components needed will be an inductor, a transistor, a diode and a capacitor. Also you will need a voltage divider (two resistors) to keep ADC input below AREF.

Yes but that will not be a regulated output. It is probable you will need a voltage regulator after that if you want a specific voltage.

there’s a guy who makes a small driver (google dr lava driver). i’d like to make my own and not have to pay 23 bux for this ;(. I also seen the lm3410… what you think grumpy mike?

Yes but that will not be a regulated output

Voltage output is connected to an ADC input channel (through a voltage divider). Regulation is handled in firmware through continues adjustment of the transistor switch frequency in response to changes in ouput voltage. A timer configured for output toggle on compare is used to generate the switching signal at the desired frequency.