Very Very Small Flasher Curcuit
Very Very Small Flasher Curcuit
(OP)
Good Day Everyone,
Once again I need Your suggestions I have been tasked with coming up with a solution and I would like to ask for your input. I need to make a Flasher Curcuit for a safety device the parameters are as follows:
1. Self contained 2. Flash about 4 times a second. 3. About the size of a stack of four nickels 4. Disposable.
I have the LEDs and battery but I need the switching portion any Suggestions? Thanks for your time Dino40
Once again I need Your suggestions I have been tasked with coming up with a solution and I would like to ask for your input. I need to make a Flasher Curcuit for a safety device the parameters are as follows:
1. Self contained 2. Flash about 4 times a second. 3. About the size of a stack of four nickels 4. Disposable.
I have the LEDs and battery but I need the switching portion any Suggestions? Thanks for your time Dino40





RE: Very Very Small Flasher Curcuit
Dan
Owner
http://www.Hi-TecDesigns.com
RE: Very Very Small Flasher Curcuit
You'll sometimes see bare chips mounted to a tiny PCB card, wires bonded, and then covered with a blob of epoxy (musical greeting cards for example). Can be very tiny.
Once upon a time (maybe 12 years ago?), there was an 8-pin flasher chip. Radio Shack used to sell it. I assume it is long obsolete. Part Number LM3909.
You could also use a discrete transistor circuit a la Forrest M. Mims III (Radio Shack circuit cook books).
Oh, there are some LEDs with flasher circuits BUILT IN.
Lots-a-Links:
www.google.com/search?q=flasher+circuits
RE: Very Very Small Flasher Curcuit
Plesae read FAQ240-1032
WEB: <http://geocities.com/nbucska/>
RE: Very Very Small Flasher Curcuit
TTFN
RE: Very Very Small Flasher Curcuit
I found a circuit with two switching transistors and a couple caps and resistors. I got it working quickly,now it's up to "the powers that be" if they want to use it.
Thanks to all for the input keep the component side up and the solder side down.
RE: Very Very Small Flasher Curcuit
It reminds me of those tiny 'Dollar Store' Super-Bright LED keychain flashlights where the Super-Bright LED is simply shorted directly across two lithium button cells.
They work fine, but who'd have thought so?
RE: Very Very Small Flasher Curcuit
Yes, the LEDs do have a shorter lifespan than they could have, but for a keychain, do most care about the difference between 50-100k hours and 1-5k hours? Probably not. Still, it would kill me to ship a product designed in such a manner... the engineer in me would cringe. Some of my products have been working for years with no visible sign of output degredation, but I current-control the suckers and underdrive them.
Dan
Owner
http://www.Hi-TecDesigns.com
RE: Very Very Small Flasher Curcuit
Mike Halloran
Pembroke Pines, FL, USA
RE: Very Very Small Flasher Curcuit
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Very Very Small Flasher Curcuit
Dan
Owner
http://www.Hi-TecDesigns.com
RE: Very Very Small Flasher Curcuit
www.microc
Just curious. Thanks.
RE: Very Very Small Flasher Curcuit
Dan
Owner
http://www.Hi-TecDesigns.com
RE: Very Very Small Flasher Curcuit
(Shame on me!)
Yes they make a ton of sense for these type projects. No one who jumps into these 555 projects ever thinks of the boundary conditions that come with them.
Death to 555s!! Long live the uuP! (and I started out in the company the invented the 555s) I have a 1/2 inch thick manual on the 555.
Keith Cress
Flamin Systems, Inc.- <http://www.flaminsystems.com>
RE: Very Very Small Flasher Curcuit
TTFN
RE: Very Very Small Flasher Curcuit
You could probably purchase a truck load of hardware for the added NRE cost of a 'Software Project'.
YMMV.
RE: Very Very Small Flasher Curcuit
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Very Very Small Flasher Curcuit
The PIC is actually much easier to get started on, and can do a whole lot more in a whole lot less space.
For flashing lights, you certainly don't need to write any code of your own; they've got app notes up the wazoo, covering every simple application you can think of, and some you wouldn't expect, and free tools that are actually pretty good.
I wouldn't even consider using "C" for this. It just adds power you won't use, and obfuscation you don't need. Step through some PIC assembly in the simulator, and you'll get it pretty quick.
Mike Halloran
Pembroke Pines, FL, USA
RE: Very Very Small Flasher Curcuit
Software Development Plan (SDP)
Software Test Plan (STP)
Software Installation Plan (SIP)
Software Requirements Specification (SRS)
Software Design Description (SDD)
Software Test Descriptionn (STD)
Software Test Report (STR)
Software Product Specification (SPS)
Software Version Description (SVD)
Software User Manual (SUM)
Software Input/Output Manual (SIOM)
Firmware Support Manual (FSM)
Version Description Document (VDD)
For a flashing LED, you might be able to 'tailor' (trim) the list a bit. But the effort to obtain authorization for tailoring would probably be significant. And there might be a whole raft of separate design review meetings just for the 'Software Project' part of the design.
And this is the pre-CMMI list. With CMMI at the higher levels, there would be more. Much more.
I ain't joking.
This probably explains why smaller companies sometimes can do things more cheaply than larger companies (not that there's anything wrong with that...).
RE: Very Very Small Flasher Curcuit
www.ti.com/ez430
"Complete...Development Tool in a USB Stick."
(Not directly applicable to the thread, but interesting just the same.)
RE: Very Very Small Flasher Curcuit
You could buy the PICs pre- programmed from a tiny company ... that you could start in your garage.
Mike Halloran
Pembroke Pines, FL, USA
RE: Very Very Small Flasher Curcuit
No documentation, no recollection of what anyone did to make the software work, no idea what a given revision of software does, no idea what the new rev(s) is(were) supposed to fix, no configuration control, no repeatability in their software builds, no guarantee that a particular build even matches what little documentation they have.
That's the "cheaper" small company. Every part shipped is custom, even if it's standard production, because they have no idea what their hardware or software is supposed to be doing in their "standard" product.
TTFN
RE: Very Very Small Flasher Curcuit
Mike Halloran
Pembroke Pines, FL, USA
RE: Very Very Small Flasher Curcuit
RE: Very Very Small Flasher Curcuit
Retail for Cdn$1.00 or less.
(= about US$.85).
I believe that they use the bare chip epoxied to the circuit card approach.
RE: Very Very Small Flasher Curcuit
Keith Cress
Flamin Systems, Inc.- <http://www.flaminsystems.com>
RE: Very Very Small Flasher Curcuit