@Silver Hawk, I recommend that you use a Microchip PIC10F200 (or 202, 204, or 206) in an 8-pin PDIP package and build a prototype circuit while you learn to program the PIC. Unless you are skilled at using teeny, tiny, microscopic-sized parts, avoid the 6-pin SMD package for now. This particular PIC is a low-end device with one input-only pin (which you will use for the push-button switch) and three input/output pins which you will use as outputs to drive three MOSFETs that in turn will drive the three Cree LEDs.
You will also need to purchase a
PICkit 3 programming pod to program the microprocessor, using free Microchip MPLAB X Integrated Development Environment (IDE) software, downloaded to your PC from the Microchip website. Be aware that there are clones available for the PICkit 3, often at considerably lower price than the Microchip website offers. I would avoid purchasing a clone. The money you might save isn't worth the headache of discovering you purchased a poorly working counterfeit. There are also reputable distributors like Digi-Key, Mouser, etc. who will sell you the real deal. Be wary of Asian eBay sellers.
Besides the PIC microprocessor (buy a few... they are cheap) you will need prototyping equipment: solderless breadboard, insulated wire jumpers, an assortment of other passive devices like switches, capacitors, and resistors. Typical ham radio stuff, really, although you should make sure the component leads aren't too large to easily fit in the solderless breadboard component-connection holes. For example, the leads on a common 1/2 watt carbon composition resistor are too large. Either solder on some 22 or 24 AWG solid wire or use 1/4 watt resistors. Some component leads are too small, 1/8 watt resistors tending not to make good contact in the breadboard component holes, especially after you have previously jammed the fat leads of a 1/2 watt resistor into the same hole.
I recommend using the 2N7000 MOSFET to experiment with while learning to use and program the PIC. Purchase a few dozen or a hundred or so (they are really cheap,
about forty cents each in small quantities) so no big deal if you let the "magic smoke" escape from a few while you climb the learning curve. Later you will need to use an N-channel, logic-level gate, MOSFET of 1 A or more current and a few milli-ohms of on-resistance to handle the Cree LED current. The 2N7000 is only good for about 200 mA, and has a relatively high on-resistance of 5 Ω, but it is easy to drive its gate with a PIC output and light up a few low-current LEDs while you learn to program the PIC.
Since your project will be battery-operated, you should consider controlling the Cree LED current with a pulse-width modulated (PWM) waveform. That means you need to sense the LED current by using the voltage drop across a very low resistance (0.1 ohm typically) in series with the return lead to common, which will usually be the MOSFET source terminal. This tiny voltage drop (about 0.6 A x 0.1 Ω = 0.06 V) insignificantly adds to the gate voltage required to fully turn on the MOSFET. It needs to be amplified with an op-amp and then digitized by the microprocessor which will then vary the pulse width to accommodate whatever average current the LED requires. I would use three PIC10F206 μPs for this, dedicating one for each LED, so you can independently control the average current through three separately driven LEDs. Don't think of small μPs like you would when selecting a processor for a personal computer: the PIC family are like jelly beans and by-pass capacitors: cheap and you use as many as necessary to get the job done. And of course you can buy ready-made PWM LED controllers... but where is the fun in that?
Using PWM means you not only save a lot of power wasted in either a linear constant-current driver or current-limiting resistor, but you also now have control of the brightness of each LED. That is extremely useful if you have separate red, green, and blue LEDs that you want to mix colors with. But this is just to plant the idea in your mind. For now, you should concentrate on getting the PIC10F200 to turn the LEDs on in the sequence you stated, using just the push-button switch to step through the sequence. It will typically take you about a month to master the ins and outs of using the PIC10F200/202/204/206 chips. I would go for the PIC10F206 initially, as it has an analog comparator built in (that you don't need for now) along with 512 words of program memory and 24 bytes of data RAM. The datasheet makes for a good rainy Saturday morning read. Print it out and keep it handy while learning to program the microprocessor.
73 de AC8NS
Hop
