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I am wanting to make a small handheld circuit that could flash anywhere between 4-6 leds in a programmed order. It has to be as small as possible and use very little energy. I am trying to make these cheap enough that I can make a lot.

I was thinking about using one of the AVR series mcu.

Size wise I was thinking of having it run on triple A'S. I am open to suggestions.

Edit I am looking for DIP MCUs not smd.

pete3
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  • Consider a boost reg, like MCP1640 to convert 1.5V to 5V to run an MCU off. – Thomas O Nov 11 '10 at 23:49
  • Consider an MCU with a wide supply range and no regulator, with a battery that operates over that supply range. If the intent is as cheap as it sounds like it is, just don't bother with regulator. – Mark Nov 12 '10 at 03:17

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Depending on how programmable/complex your flashing is - you may be able to do it without software. In which case:

Most Simple Stoplight circuit

Blink an LED with just a capacitor?

If you do need to use a microcontroller - with 6 I/O pins which is low power and small then I'd look at:

MSP430 (Value Line). Here's an app note on powering an MSP430 from a single cell (using a charge pump). There's also now an MSP430 which runs at 0.9V.

AVR PicoPower is also worth a look. Even the ATMega168/328 used in Arduino though can be put into quite low power modes.

Here's a couple of Arduino libs to do it:

http://code.google.com/p/narcoleptic/

http://www.arduino.cc/playground/Code/Enerlib

Community
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Toby Jaffey
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  • Find any through hole MCUs like those, that's what I need. – pete3 Nov 12 '10 at 00:09
  • I'd go for the MSP430G2211. Here's a couple of my projects which might be relevant: http://blog.hodgepig.org/2010/09/12/577/ http://blog.hodgepig.org/2010/09/30/jam-jar-lamp/ – Toby Jaffey Nov 12 '10 at 00:17
  • What would you suggest using to power this? I want it to be a low profile and small as possible? Think 4 double A's would work good? – pete3 Nov 12 '10 at 00:44
  • 4 x AA would be fine, but I'd go with 2 x 1.5v coin cells or a CR2 for 3v – Toby Jaffey Nov 12 '10 at 00:55
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    Using a microcontroller for a simple LED sequencer seems like overkill. The most complex I'd go for would be a 555 timer driving a binary counter used to run through some of the address lines of a PROM/EPROM programmed with the required bit/LED patterns. By using switches on the higher address lines and putting the required patterns at the relevant locations in the (E)PROM you could even switch between patterns. – Linker3000 Nov 12 '10 at 22:15
  • The [Atmel ATtiny43U](http://www.atmel.com/dyn/products/product_card.asp?part_id=4523) has an integrated charge pump that runs down to 0.7 V and provides up to 30 mA (@ 1.0 V, 10 mA @ 0.7 V). Alas, it is SMD only, but such is the price of high integration. – Nick T Nov 18 '10 at 21:16
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Have you looked at the MSP430G2231? It's really low power and is pretty cheap too. Plus it isn't a SMD MCU.

sptrks
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if you want cheap you dont even need a micro controller for simple on/off. Infact i would avoid them alltogether. a Simple sequence of leds that repeat you could use a simple 555 timer and a counter module, i cant think off which ones off the top of my head but there are lots of option and would take some time to plow through data sheets.

Andrew
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  • A favourite at school electronics clubs was a 4017 CMOS decade counter clocked by a 555 timer. The best variant I saw was with the 4017 being used as part of the resistor timing chain on a second 555 timer running in astable mode. By using the 4017 to switch between up to 10 variable resistors you could make a simple tone sequencer that drove everyone mad after a few minutes! – Linker3000 Nov 12 '10 at 22:10
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You might also look at the MiniPOV. It's the simplest, smallest, and lowest-cost way to flash LEDS with a microcontroller that I've ever seen. But I'm sure you can find some way to "trim the fat" on this project :-).

I've been told that lots of designers find it easier to make a new system when they can start with a "scaffolding" of a known-working system, even when they end up completely changing everything so there isn't any part of the scaffolding remaining.

Using a microcontroller for a simple LED sequencer seems like overkill, but any alternative I can think of requires more than 1 components to replace the 1 microcontroller chip -- and how can "more components" be simpler?

davidcary
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Have you seen the Throwie that blinks in Morse code? Instructables and Ward's own website. It uses an 8 pin DIP microcontroller (less than $3 in ones).

davidcary
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