I've seen single and dual blinking circuits, but wanted to know if there was some easy way to squeeze in a third? I don't have a 4017 IC at the moment, unfortunately.
Any way to create a 3 LED chaser with only a 555 IC
555led
Related Solutions
You should tie the /RESET pin to Vcc. If you have a CMOS type this can keep it from working.
Pin 5 may be optionally connected to ground through a 10nF capacitor, but leaving the pin open will not keep the circuit form working.
Your power supply needs two connections (only one is shown connected in the above schematic), but it should not be as high as 8.4V. The module specifies no higher than 6V. I suggest an LM7805 regulator to give you 5.0V if you don't have such a supply available. It's not clear whether excessive input voltage would damage the module, so I would avoid it.
The circuit you show will allow the average light to be varied from mostly on to around half brightness. If you want more range than that, it's better to use a couple diodes with the circuit. If you have the CMOS type there is an even better way to connect it- leaving pin 7 open and using the output. You can test the 555 output with an LED and resistor to GND- it should vary the brightness- before connecting it to the module.
As Russell says, your 555 timer circuit looks a bit off. Search for 'astable 555 circuit' to get your square wave generated. There are online calculators to set the values of the resistors and capacitors.
To get 0.2Hz you will need about 50K for R1 and R2 and 47uF for C:
Now the reason that you are just seeing a flash when you changed to a MOSFET is that their gain is so high. So even if you are using your R1 and C1 to generate a ramp, the on/off voltage of the MOSFET is probably crossed immediately.
What you need instead is an NPN transistor that can handle the current that you need for your LEDS. Just find out how much current you are drawing for the LEDs and check the datasheet of the transistor to see if it will work.
Here's a circuit that I simulated that gives a pretty good ramp up and down at 20mA. Not sure how much current you need but that might be a pretty good start.
I used a 0.2Hz square wave instead of the 555 just for simplicity.
To slow down the ramp up/down time increase R1 or C1. Because R1 is connected to the base, this will also effect the brightness of the LED. So it might be better to choose a good value there first and then change C1 for the timing.
Best Answer
This could be done, but it would be a lot simpler to just get a shift register IC or small microcontroller. The schematic would be quite large, and I'm not going to design it for you. Here is a block diagram and some things to research.
simulate this circuit – Schematic created using CircuitLab
First, a square wave is fed into an integrator to generate a triangle wave. The triangle wave is sent to 3 window comparators. You can adjust the windows and square wave frequency to get the desired chase.