Need Help with a Slightly. Different LED Flasher Circuit - Novice Here!

SamR

Joined Mar 19, 2019
1,639
Yup I have some 1k,2k,4ks to play with after I finish Grobb's. Only 1 1/2 chapters left. Cost-wise compared to what's on a UNO at it's price they ought to be almost free instead of a buck a pop.
 

Wolframore

Joined Jan 21, 2019
1,536
whats grobbs? I have the 1, 4 and 8k... those 8's are almost same as the 328's but I keep them for pin compatibility. Have you seen the newer Tiny's? 416... etc. They spec even better and less expensive.... but they changed everything.
 

SamR

Joined Mar 19, 2019
1,639
Grobb's Electronic Principles textbook. I bought 2 of the new Tiny modules and a couple of the ATTiny dip socket modules and some ATTinys to play with when I go back to programming. Also looking into standard AVR programming with the Arduino IDE. Lots on the todo list. That and playing around building an AM rcvr. Gotta throw some RF in there since I am a HAM. Ooops I did buy a couple of 85s. Forgot I had them. Bought a couple of Atmel ATMEGA 328s long ago in case I torched the uP on a UNO that are gathering dust too. Kinda getting off-topic...
 

Thread Starter

ninjagrips

Joined Nov 14, 2019
11
Okay, so that's several different options! Thanks, folks!

I do not know how to code, I'm really hoping I won't have to go down that road, and I'd like to get this done with 80s components, if possible, the more I think about it.

SamR, if I went your route, would I need transistors? Are you suggesting I go with the simple Astable Multivibrator, or something else? How would I incorporate the switch(es)?

Wolframore, I love your idea, but my knowledge with programming microcontrollers is non-existent. You ARE correct though, about the blue Cap and the red jumper wires! Apparently, there's a slide switch at the very front of the box, as well, hidden by the edge connector card in most pictures. You clearly see Mark Hamill flip it on, in the scene, though. Also, unfortunately, those are the best pics I've got of the real board. Some of the parts have been identified, but the board and the IC are unknown.

AnalogKid, your suggestion makes the most sense, to me, I'm just not clear on the way the switches should be wired. And would a toggle or rocker be absolutely necessary, or could a momentary or something else be used? I've got lots of little momentary switches, and back to SamR, I've got a bunch of those slide switches, as well! I'd love to hear more or see how the circuit you're describing would be wired. I've been watching a bunch of Youtube videos, and one guy's channel has a little tutorial for drawing a simple 555 timer circuit in EasyEDA, which I'm working on.

I'd love to be able to put this project's circuit together using EasyEDA, and maybe have a PCB made?

If I go the simpler route, and "dead-bug" wire it, or somehow manage to fit it all on a little board, I'd love to know what components I'd need, and how the switches would be hooked up in the circuit. I've got lots of stuff here, already, but likely not everything I'd need.

I really appreciate everyone's suggestions, help and input! You've taken me much farther than I would've done on my own!
 

djsfantasi

Joined Apr 11, 2010
5,956
Dude, ever hear of SMD? I could fit all that a few times over in that space.
LOL! SMD ain’t gonna save space for the ICSP headers. And no one said nothing about not using SMD for the half dozen external components. The whole thing fits within a 16 pin dip footprint (less the switches). rd. But
 

Wolframore

Joined Jan 21, 2019
1,536
I saw 16 x 46mm for the space. SOP8 is only about 6mm wide so pads add about 1.3mm. ICSP does not have to be 2x3 which is about 5mm x 8mm... can be inline. Or just jump the pins. If using micro I wouldn’t use toggle since the sequencing can be done in code. You can still do one resistor, just tie it to source, switch low side with logic low. That way if someone does switch both you’re still safe. Anyhooo... I’m always trying to cram things into tiny places
 

SamR

Joined Mar 19, 2019
1,639
You can dead bug a NE555 or to save battery power the CMOS version such as ICM7555 which draws 40uA instead of 3mA. One switch to turn power on/off. 2nd to take the 555 output pin to one LED or the other. No transistors neccesary. Resistors and capacitor to set the timing. The 555 powers @5VDC (3VDC min) so a 5V coin battery will power it and one led at a time easy. May not be bright enough for full sunlight but work fine in subdued lighting. How long is the question but at least a couple of hours on a fresh battery I would think? The switches in my previous post are SPDT so center pin to either endpin to select pin 3 timer output for 2 circuits or center pin to one end for simple on-off.
 
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SamR

Joined Mar 19, 2019
1,639
OK you are going to need 2, 3V coin batteries 22mm dia x ~5mm deep (total) to give you 6V nominal which gives 200+ mAH. which at a full 20 mA for a LED is 10 hours and realistically @10 ma ~20 hours. Not too bad. You can try breadboard/testing it with one battery but @ 3V min for the 555 you should use 2 to get 6V nominal.
 

Thread Starter

ninjagrips

Joined Nov 14, 2019
11
Hmm, 22mm diameter is too big, for the batteries. What's the requirement voltage-wise for the ICM7555?

I suppose the other option would be to use transistors.

Thank you so very much for your help, ALL of you!
 

Wolframore

Joined Jan 21, 2019
1,536
You did a nice job on your model, is there room to hide a battery in the main part? Most battery are too big for that case. I’m sure the actual prop made use of the entire cavity.
 

AnalogKid

Joined Aug 1, 2013
8,256
AnalogKid, your suggestion makes the most sense, to me, I'm just not clear on the way the switches should be wired. And would a toggle or rocker be absolutely necessary, or could a momentary or something else be used? I've got lots of little momentary switches, and back to SamR, I've got a bunch of those slide switches, as well! I'd love to hear more or see how the circuit you're describing would be wired.
A momentary switch can be used, but it increases the circuit complexity as now there has to be an electronic toggle circuit instead of a mechanical toggle switch. Not a huge deal, but more parts to solder. I"ll see if I can whip out a schematic. A 74AC14 can be the oscillator, toggle flipflop, and LED drivers. What is the power supply voltage?

ak
 

SamR

Joined Mar 19, 2019
1,639
One on/off switch to put power from battery positive to pin 8 (center lug of switch). Negative side of battery to pin 1 (end lug of switch). Center of 2nd switch to pin 3 to select red or grn LED output (one on each opposite end lug). I suck at paint LOL. All grounds connected to battery neg. Vdd on each side of chip connected together on pin 8. Be careful dead bug soldering to pins not to cook the chip. Use liquid flux to get a fast good solder bond. I have some small, flat-billed, all copper alligator clips I use as heatsinks for the pins when soldering to protect the chip. Meuller #34C. Typically flatten the pins out being careful not to break them off and trim the narrow pin insertion part off. Pin 4 resets on lo input so connect it to +. Test it after soldering and if working like you want paint it with conformal coating to insulate. Pin 5 typically has 10uF capacitor to ground. I have some 30AWG stranded silicone insulated wire that I would use due to its flexibility and heat resistance while soldering.

Capture.jpg
 
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Bernard

Joined Aug 7, 2008
5,359
It will be tight but all will fit inside the box. Battery, CR11108, CR1/3N, 3V Li, 11.6mm D X 10.8 mm H, 160 mAh. C555 with one SM transistor driver or my favorite Nch. LL FDD6530A SMT; SWs opposite LEDs and on same end under the cover.
Adding a diode to C555 ckt. could cut duty cycle to 30% to save juice.
Mounting board is 1 mm fiberglass. Wire is 30 Ga Kynar wire wrap wire.
If you were in USA I or we could supply most of the parts.
 

Thread Starter

ninjagrips

Joined Nov 14, 2019
11
It will be tight but all will fit inside the box. Battery, CR11108, CR1/3N, 3V Li, 11.6mm D X 10.8 mm H, 160 mAh. C555 with one SM transistor driver or my favorite Nch. LL FDD6530A SMT; SWs opposite LEDs and on same end under the cover.
Adding a diode to C555 ckt. could cut duty cycle to 30% to save juice.
Mounting board is 1 mm fiberglass. Wire is 30 Ga Kynar wire wrap wire.
If you were in USA I or we could supply most of the parts.
This sounds great! And I am indeed in the US. Atlanta, GA.

I do already have some really nice 30 Ga wire from installing lightsaber FX boards, so that's lucky.

Where would I get the components? And the board? Or should I draw this in EasyEDA and have a custom PCB made?

Also, I do have these tiny BR435 cells, but I'm guessing the mAh is really low. Still, they're really cool looking, and TINY, and they look the part, ya know?

I'm seeing some cheap C555 chips on eBay, versions that only require a min of 2V, if the Wiki is correct.

https://www.ebay.com/itm/7555CN-CMOS-Timer-Oscillator-Intregrated-Circuit-by-Philips-ICM7555CN-ICM7555/222788201847
https://www.ebay.com/itm/Custom-Silicon-Solutions-CSS555-ID-CSS555-Micropower-Timer-DIP-8-3-pcs/112229773105
As for the question about supply voltage, I was planning at first to use 2 LR44 cells, something like that. Which would mean 3V.

I DO have one of these (don't mind the actual box, just the custom PCB with the little SMD LEDs on it), which does ALMOST what I want, but the board is just a bit too long, even after filing away ALL excess. It's not really set-up the way I'd like, either. It uses the two black buttons as real switches, and I'm not down with that. But, I thought I'd show y'all, in case someone sees a way it could be modded somehow, to suit my needs. I probably should've brought this up earlier, but I really didn't think it could be an option. Still, here's the link and there's a video with a guy explaining how to get it working.
 
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SamR

Joined Mar 19, 2019
1,639
versions that only require a min of 2V,

Remember you also have to power the LEDs and they get dimmer with less V. As to components they might have them at a Fry's near you or Digikey w/ $4.99 1st class mailing for small lots.
 
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Wolframore

Joined Jan 21, 2019
1,536
That’s why I like uC design... this is all you need. Actually take one led out on below.. it’s all in coding.

could be run at 3.3v, Vf of red and gr led should be about 1-6-2.1v

power up start blinking whatever you want.. then switch colors
do this as many times as you like
power down into low power mode and go to sleep or add a latching circuit and actually cut power


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