Cheap small self contained microprocessor

Using Arduino Microcontrollers
#1

I decided to make Christmas ornaments for my family using the Adafruit Neopixel ring (http://www.adafruit.com/products/1463), and I was wondering what are my options for a self contained chip set that can do a neopixel ring. I would prefer to have the microprocessor come complete without major soldering needed, as I am not that good at soldering (hey, I'm mostly a software guy).

While the Gemma, Trinket, or Digispark would work fine, I was wondering if there were cheaper boards for a quantity 6 order from a North American seller. I have an Uno R3 that I could use to do the programming for the chip.

I bricked my Trinket and Gemma, and so far I haven't been able to use the Adafruit bootloader restorer that runs on the Uno to restart them. Right now, I am somewhat down on those two boards, and may go for the digispark (which is $1 more).

I do have a hardware ISP on order to reset the trinket/gemma, but since it is on a slow boat from China, I don't expect to get it before we start thinking about sending the gifts out.

#2

The Digispark is an ATTiny85 with a voltage regulator. If you have another Arduino (UNO maybe?) to do the programming, you can just use an ATTiny85 by itself. Maybe a DC-to-DC voltage regulator to hook up the battery.

That would require minimal soldering and money wise you could end up far under $3.

I'm a software guy and I can do that much soldering...

#3

int2str: The Digispark is an ATTiny85 with a voltage regulator. If you have another Arduino (UNO maybe?) to do the programming, you can just use an ATTiny85 by itself. Maybe a DC-to-DC voltage regulator to hook up the battery.

That would require minimal soldering and money wise you could end up far under $3.

I'm a software guy and I can do that much soldering...

Thanks. As these are Christmas ornaments, I assumed I would power it via a USB charger cable that plugs into the wall socket, and not a battery. Any particular place you would order the ATtiny85's from?

#4

MichaelMeissner: Thanks. As these are Christmas ornaments, I assumed I would power it via a USB charger cable that plugs into the wall socket, and not a battery. Any particular place you would order the ATtiny85's from?

I like to order from Digikey. They ship within the US in very few days.

Part numbers: ATTINY85-20PU-ND - ATTiny85, 8-pin DIP package ($1.29) A100204-ND - 8-pin DIP socket ($0.29)

#5

Arduino Pro Mini is pin-compatible with Arduino Uno and quite small (34mm*18mm):

Under $4 each on eBay: http://www.ebay.com/sch/i.html?_nkw=arduino+pro+mini (half the price of a digispark!)

( nb. You’ll also need an FTDI adapter to program them, eg.: http://www.ebay.com/itm/320907184616 )

#6

MichaelMeissner: I do have a hardware ISP on order to reset the trinket/gemma, but since it is on a slow boat from China, I don't expect to get it before we start thinking about sending the gifts out.

There's a new breed of Pro Minis on eBay that has ISP interface as well as FTDI.

Look for the boards with a double row of pins at one end by the reset button...the price is about the same as the old ones.

#7

fungus:

MichaelMeissner: I do have a hardware ISP on order to reset the trinket/gemma, but since it is on a slow boat from China, I don't expect to get it before we start thinking about sending the gifts out.

There's a new breed of Pro Minis on eBay that has ISP interface as well as FTDI.

Look for the boards with a double row of pins at one end by the reset button...the price is about the same as the old ones.

Thanks, though the US price isn't all that cheap ($6.75 on ebay for the old version, none of the US sellers seem to have the new one). I can see cheaper china versions, but as I said, I don't want to order from China, given how long it takes the normal order, and the fact that my wife always pushes to ship early so we get reasonable priced shipping.

#8

int2str: I like to order from Digikey. They ship within the US in very few days.

Part numbers: ATTINY85-20PU-ND - ATTiny85, 8-pin DIP package ($1.29) A100204-ND - 8-pin DIP socket ($0.29)

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.

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

#9

MichaelMeissner: While the Gemma, Trinket, or Digispark would work fine, I was wondering if there were cheaper boards for a quantity 6 order from a North American seller. I have an Uno R3 that I could use to do the programming for the chip.

My hex uploader can upload any data to the AVR line of chips (like the 328, Tiny84, Tiny85 etc.).

http://www.gammon.com.au/forum/?id=11638

To simply replace a bootloader:

http://www.gammon.com.au/forum/?id=11635

#10

Thanks Nick. If I go with that approach, I need to get a SD card reader for the Uno.

#11

MichaelMeissner:
Thanks, though the US price isn’t all that cheap ($6.75 on ebay for the old version, none of the US sellers seem to have the new one).

Still cheaper than a Digispark…or an hourly rate for soldering Tiny85s together.

MichaelMeissner:
I can see cheaper china versions, but as I said, I don’t want to order from China, given how long it takes the normal order, and the fact that my wife always pushes to ship early so we get reasonable priced shipping.

Some of the sellers have a $3 shipping option. I usually get them in 7-10 days if I choose that (to Spain). Go through the auctions and look at “Shipping and Payments” to find sellers who do it, eg. This one: http://www.ebay.com/itm/140966034693

We’re still in October. The slowest eBay shipping I’ve ever seen took about a month (YMMV).

If your buying a dozen or so I’m sure there’s somebody on aliexpress who’ll send them via. courier for a reasonable price and they’ll arrive in two days. I’ve ordered LED strips from China on a Friday afternoon and they arrived on Monday morning.

#12

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

PCBs (perfboard) Six-pin headers for ISP prigramming 0.1uF ceramic capacitors for decoupling

You don't need a voltage regulator if you're using a USB charger, they have built-in regulation.

#13

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.

#14

fungus: We're still in October. The slowest eBay shipping I've ever seen took about a month (YMMV).

If your buying a dozen or so I'm sure there's somebody on aliexpress who'll send them via. courier for a reasonable price and they'll arrive in two days. I've ordered LED strips from China on a Friday afternoon and they arrived on Monday morning.

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.

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).

#15

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?

MichaelMeissner:
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. :slight_smile:

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

#16

int2str:

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...)

#17

MichaelMeissner: 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!

#18

fungus: (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.

#19

fungus:

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.

MichaelMeissner: 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).

fungus: 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.

#20

int2str:

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.

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.