NOW IT WORKS!

Hey!... I'm getting good at this...

 

Ok, here's a preliminary of the PCB, I made it as compact as possible... see if you can fit it in most of your models. You need to buy the connector for the battery, and use extension wire from the PCB to where you are planning to physically place the LED.

Parts list is (one of each):

• resistor 470 ohms, 1/4 watt
  
• resistor 33 Kohms, 1/4 watt
  
• transistor BC547C, or 2N2222, or 2n3906
• electrolytic capacitor 100 µF at 16V (or at 10V, if you like)
• 555 IC
• 1N914 diode
• LED

I'll try to modify the circuit later on for it to flash two alternating LEDs, maybe then you could use two colors.

Let me know if there's anything else you need.

Thank you so very much!. Last time I almost drove poor Sarge to drinking. This one seems simple. How do I adjust the flash rate? Again thank you!!

 

Thank you so very much!. Last time I almost drove poor Sarge to drinking. This one seems simple. How do I adjust the flash rate? Again thank you!!

All you have to do is change the values of the capacitor and/or the 33k resistor. In fact changing the resistor is more practical. The larger the value, the longer the flash rate.

 

And btw, let me know if you'd also like to have the layout for the double flasher's PCB

 

And btw, let me know if you'd also like to have the layout for the double flasher's PCB

Oh yes and also one that flashes and the other that does not.

 

WOuld this work?

 

Hola torpedo,

What is the most comnplex sequence of flashes in any lighthouse that you remember?

Myself, having used them to identify lighthouses for years (albeit, many years ago) I recall a group of (a group of) flashes plus one or two single ones of a different color.

 

I think it is red on 3 of 2 green on 2 off 3

 

WOuld this work?

That's a timed relay board. If you intend to use it for your miniatures then it'll eat through the battery too quickly. It'll also make annoying clicking sounds.
Another thing about the single LED circuit. You may want to change the 470 resistor to a higher value to dim the LED a bit... say 700 or 1k

 

Thank you for your help! Got parts coming and etching the boards!!

 

Wait a sec - I think you ought to actually breadboard up that circuit before you go to the expense of having boards made.

For one thing, I can guarantee that it won't work from a 3v supply as you specified. The simulation has it powered from a 9v source. However, 9v batteries are VERY expensive for their power output, particularly nowadays - and that isn't an especially efficient circuit.

It looks like you're using the NE555 model that LTSpice comes with. Beware; that is an "idealized" 555 model, which you can't actually buy. The closest you might get to it is a CMOS 555, but the CMOS version won't source as much current (10mA) as the BJT (transistorized) version will (200mA), but the transistorized version won't get within about 1.3v of Vcc with even a light load on the output (pin 3) due to the output being a Darlington voltage follower. Also the BJT version uses three 5k resistors in series internally to establish the 1/3 & 2/3 trip point voltages; at 9v that's 0.6mA current flow. The CMOS version uses three 100k resistors in series for 30uA current flow.

You don't show bypass capacitors across the 555 supply. Failure to include them can result in erratic operation.

 

Wait a sec - I think you ought to actually breadboard up that circuit before you go to the expense of having boards made.

For one thing, I can guarantee that it won't work from a 3v supply as you specified. The simulation has it powered from a 9v source. However, 9v batteries are VERY expensive for their power output, particularly nowadays - and that isn't an especially efficient circuit.

It looks like you're using the NE555 model that LTSpice comes with. Beware; that is an "idealized" 555 model, which you can't actually buy. The closest you might get to it is a CMOS 555, but the CMOS version won't source as much current (10mA) as the BJT (transistorized) version will (200mA), but the transistorized version won't get within about 1.3v of Vcc with even a light load on the output (pin 3) due to the output being a Darlington voltage follower. Also the BJT version uses three 5k resistors in series internally to establish the 1/3 & 2/3 trip point voltages; at 9v that's 0.6mA current flow. The CMOS version uses three 100k resistors in series for 30uA current flow.

You don't show bypass capacitors across the 555 supply. Failure to include them can result in erratic operation.

You are absolutely right in all counts.. I assumed that the OP would first test the circuit before etching... and my biggest omission was indeed the bypass cap. What's the recommended value for a 555? Would 10uF suffice?
On the other hand, I did show a far more efficient alternative working at 1.5v only. It's in post #29

 

Recommendations are 0.1uF ceramic or poly metal film in parallel with a >= 1uF aluminum electrolytic. When the output changes states, there's a momentary dead short across the supply. If there are more than a couple inches of wire between the IC and supply, the inductance becomes significant, and the transient during the state change will be quite large. 100uF will usually be quite sufficient, and will also help to extend battery life.

 

Ugg ok I should breadboard first. That makes sense 9 volt battery will work fine. I need a power supply that is thin enough that I can route out a batter holder in the base of the bottle stand.

 

How do I determine what resistor to use to control flash length?

 

How do I determine what resistor to use to control flash length?

Let me redraw that pcb for you with the required bypass cap and I'll get back to you. What range of flash length would you like to have?

 

I think it is red on 3 of 2 green on 2 off 3

Hola torpedo,

Thanks for replying.

You surely will laugh but my English fails between of and off. Could you draw it even roughly? Gracias

 

It would vary between lighthouses. But I can make do with on with 3 seconds off the on 3 sec off.

Thanks!!

Don

 

Don,

The following table will give you an idea of the cycle length for the circuit (assuming that you'll be using the circuit whose PCB I drew for you) If cycle length is 10 seconds, then it means that the LED will be on for 5 seconds and off for another 5 seconds.

Assuming a value of R8 = 33k

For values of C1 then (approximate values):

C1     cycle length
  2 µF    0.30 sec
4.7 µF    0.60 sec
10 µF    1.25 sec
22 µF    3.00 sec
47 µF    6.50 sec
100 µF   14.00 sec
200 µF   17.75 sec

So to get 3 seconds on and 3 off, you just need to use a 47 µF cap

IMPORTANT: Please discard the previous PCB that I drew for you and use the one attached instead. This version includes the recommended bypass capacitor (shown as C2). Also, before etching, first TEST the circuit by assembling it on a breadboard, as @SgtWookie suggested.

 

Still waiting on parts from China. With no radio shack It takes forever!!!!