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Topic: Cheap small self contained microprocessor (Read 12518 times) previous topic - next topic

fungus


Six-pin headers for ISP prigramming


To keep the soldering to a minimum and the PCB size small, I would simply program the chips in a bread-board  and them plug them into the socket. Can also do the prototyping on the breadboard.


That would work too.

(although I bet you have to pull them all out and reprogram them a few times at the last minute. You know what software's like...)



Advanced Arduino

fungus


I've had at least 3 ebay auctions that never showed up, and 1-2 that eventually showed up 2-3 months later.  So, while I will buy stuff I don't need immediately from China/Singapore/etc. I would buy anything that's critical, unless it is from a supplier I've used before and trust.


Moral: Order a bunch of Pro Mini's today - be prepared for the next project!
Advanced Arduino

Paul__B


(I don't live in the USA so US sellers aren't any faster for me ... they're just double/triple the price)


Wow!  That is cheap!  Most of the time they seem to want to charge $50 shipping for a $10 order.

MichaelMeissner



I've had at least 3 ebay auctions that never showed up, and 1-2 that eventually showed up 2-3 months later. 


Out of how many?


Probably 100 or so, total.  However, recently, it seems I've had more slow deliveries from trans-border shipments (including one from Canada which in theory doesn't need to go through customs).  Yeah, the odds are that it will get here in time, but I really would prefer not to go that route.


In terms of paying for faster shipping, for most things, it winds up roughly the same cost or cheaper, if I order from a US vendor and use the US post office than use the Chinese shipping options that claim to expedite the shipping (and there still is the customs lottery that seems to hold things up on a random basis).



Yeah, I guess that makes sense if you live in the USA.  :)

(I don't live in the USA so US sellers aren't any faster for me ... they're just double/triple the price)

But I would assume you would use European Union sellers for much the same reason I choose to order from USA sellers.

MichaelMeissner


Six-pin headers for ISP prigramming


To keep the soldering to a minimum and the PCB size small, I would simply program the chips in a bread-board  and them plug them into the socket. Can also do the prototyping on the breadboard.

Yeah, I assumed I would have only one programming setup (using a dip-8 socket), and then plug the board into some small perfboard when I am satisified with the results.

fungus

#20
Oct 28, 2013, 10:31 pm Last Edit: Oct 28, 2013, 10:36 pm by fungus Reason: 1


(I don't live in the USA so US sellers aren't any faster for me ... they're just double/triple the price)


Wow!  That is cheap!  Most of the time they seem to want to charge $50 shipping for a $10 order.


Not all of them do that ... only about 90%.  :smiley-roll-blue:

eg. This guy sells Pro Minis for $6.99 with $6.55 shipping to Spain.

http://www.ebay.com/itm/181135691363

Not too bad ... but I can get three of them from China for the same money.
Advanced Arduino

fungus


But I would assume you would use European Union sellers for much the same reason I choose to order from USA sellers.


Usually it's best not to be in a hurry...

But ... if I am in a hurry then things like Fedex/DHL/etc. can make shipment slower. The customs people seem to assume only business people use those and they don't mind paying import tax. Not only do I get to pay 40 Euros extra (mostly administration fees so you'll pay that much for a $2 item), they can also delay parcels by an extra week, no problem.

I've never had a packet from China stopped by customs. Not one. Many of them turn up in about 10-12 days.

FWIW, I've had quite a few ebay items from Thailand arrive in 4-5 days via normal post. I'm not really sure how they do that.

The fastest thing I ever got from China was some LED strips via "EMS" (usually the cheapest 'courier' option on Aliexpress). They took two days to arrive and LEDs+shipping cost me no more than the equivalent LEDs on eBay with free shipping.

Advanced Arduino

Coding Badly

#22
Oct 28, 2013, 11:58 pm Last Edit: Oct 28, 2013, 11:59 pm by Coding Badly Reason: 1
Ok, the problem I have with ordering with Digikey, Mouser, etc. is just the shear number of parts that they offer, it can be hard to narrow down what to buy.


The "normal" version...
Digi-Key
Mouser
Avnet Express

The low-voltage version (10 MHz maximum clock)...
Digi-Key
Mouser
Avnet Express

Quote
Is there anything else besides the ATtiny85, DIP socket, and voltage regulator that I need?  Capacitors?  Resistors?  Etc.?


10K pull-up resistor for reset.  0.1uF capacitor for bypass.

nickgammon


Wow!  That is cheap!  Most of the time they seem to want to charge $50 shipping for a $10 order.


I wanted to buy one of these:

http://shop.evilmadscientist.com/productsmenu/tinykitlist/652

But I'm not paying $40 shipping for a $35 order. :(
Please post technical questions on the forum, not by personal message. Thanks!

More info: http://www.gammon.com.au/electronics

MichaelMeissner

Thanks Coding Badly.  Now to wait for digikey to do the account verification, etc.  It looks like it would save quite a bit over the trinket, etc (about $30US for the amount I was planning on ordering).

Docedison

@ Nick... I attached the real component "Data Sheet" (Schematic using real common parts)  No Fancy "Machined semi rigid poly...) But half the challenge of a project like that and most others too.. Is packaging it. there are a bunch of nice clear PVC enclosures that would look good wrapped around that.. (BTW the 'data sheet' was an open download..

Doc
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

MichaelMeissner


I wanted to buy one of these:
http://shop.evilmadscientist.com/productsmenu/tinykitlist/652

But I'm not paying $40 shipping for a $35 order. :(

I suspect you have to be of a certain age to appreciate this in all of its glory, and have actually designed 555 circuits.  I did look up 555 circuits at one point, but the application I wanted to use it for (telegraph key acting as shutter release for my steampunk camera).  I've switched to using my Uno and Teensy 3.0.  I imagine, soon it will be ATtiny85's.

In terms of 555's, the older generation probably thinks the smartphone apps that calculate all of the resistor values is making the younger generation all soft (in my day, we walked 10 miles uphill through 3' of snow both ways to get to school).

However, the size and price just reminds me of the urban hipster catalogs and email postings I get occasionally, where the prices are out of this world, for those 'special' people.

nickgammon


I suspect you have to be of a certain age to appreciate this in all of its glory ...


But I am of a certain age!
Please post technical questions on the forum, not by personal message. Thanks!

More info: http://www.gammon.com.au/electronics

MichaelMeissner



I suspect you have to be of a certain age to appreciate this in all of its glory ...


But I am of a certain age!

Yeah, and if I had done the EE side of things instead of programming, I probably would be enamored of it too. :-)

I'm trying to remember what I paid for them, but I suspect I will pay less for the ATtiny85's than I bought the 555's I have in my someday drawer from the local guy that sells electronics retail.  $)

nickgammon

I've got an ATtiny85 flashing an LED every couple of seconds. I suppose I could make a 555 do that, but why use hardware when you can do it in software?

Besides, I think my solution is better with power. It would be down to about 8 µA for almost all of that 2 seconds, and the flash is only 1 mS long. The whole thing runs from a CR2302 cell.

Here:



The ATtiny is sandwiched between the chip socket and the battery socket. Small part count, as you can see. The yellow dots in the background are the LEDs over my bench.
Please post technical questions on the forum, not by personal message. Thanks!

More info: http://www.gammon.com.au/electronics

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