Let's Make Robots!

Digispark - Small (19mm x 26mm) Arduino / USB Dev

So much!

So a while back I splashed a little cash on Kickstarter. I hadn't seen or heard of any Arduino's that were as small as the Digispark and I thought it'd be interesting to play with. I pledged a little higher than I should of, with the intention of sharing the Digisparks around (to split the cost of delivery and customs charges) and when they started offering shields to go with the Digisparks I put my name down for several.

That was in September. Roll forward to today when I received a little parcel in the mail.

First thing that caught me by surprise was that it was just a little parcel. These Digisparks don't take up much room at 19mm x 26mm (less than an Inch x an Inch) and even with breakable headers, sockets and shield kits the parcel was pretty light.

First thing I did was upload an LED blink test script. Naturally I went on to tweak the test script so it glowed instead of flashing. Unfortunately that was all I had time for during my lunch break. When I got home from work I quickly put together an RGB LED shield and tried the test script, it did a good job of blending the colours together and I started pondering what uses I was going make of these interesting little boards.

At only 6 I/O pins (two are shared with USB, so there are only 4 I/O pins available if you want to use it plugged into a computer), things may be a little limited but who doesn't enjoy a good challenge?

The Digispark has hardware I2C support so those few I/O pins could be put to good use with items such as this LCD or a range of sensors.

I'll have to stop here for tonight. Hopefully I'll be able to share some examples and interesting uses of the Digispark in the near future.

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Nice gadget but not new :-)

http://letsmakerobots.com/node/32907

The cool thing with the ATtiny85 is the limitations, you need to think and this challenge is what I like.

One of my friends made a slightly bigger version with the ATMega328

 

Very nice implementation lumi.

It's certainly not a new idea but this is reasonably accessible (no need to etch boards or have an ISP), especially when combined with the idea of shields.

I remember trying to scale one of my projects down by going for an 8-pin PIC (this is going back several years, can't remember the exact project) but having only programmed 18-pin PIC16F84A's I was out of my depth. I'd feel a lot easier about picking up some ATTiny85's after prototyping the system with a Digispark or something like your board.

Right, to scale down a project is the Attiny a good choice even if the price is not much lower than a ATMega168 or 328...

Can you show a picture from the backside of the board. There must be the USB controller, right?

Lumi, I'll get a photo of the under-side for you. No USB controller, the ATTiny85 handles that (hence it can behave like a keyboard, mouse, joystick, etc if you want) and the only down-side is the 5sec delay at power-up where it checks to see if it is being programmed.

Got it...thanks.

Am I right the boards are based on the Attiny85?

For K120189: The arduino servo library does not work on the Attiny85. But I think you can find a modified software servo library for it. Attiny's only have 2 8 bit timers and no 16bit timer (like the ATmega328). So libraries that need the 16bit timer (like the servo library) wont work.

There's a lib called servo8bit.h but it sucks-as in no one I've ever talked to who's tried to use it has had any success. However you can bit-bang it to some extent. See what I did with Pip5queek for example when I needed to run PWM and a servo at the same time on pins that had "broken" PWM if I had used servo.h. If a delay (even a microsecond delay) throws off your code then you can always use the if ((micros-lastInterval)>=targetInterval) method.

Yes Bajdi, it's got a little ATTiny85 on it.

There appears to be a thread on the digistump forums regarding a servo library for the digispark. Not given it a proper read myself though.

That little board would be perfect for bob! Where can I find one
Digistump.com

They don't have a price on per-orders, only flat shipping. Odd...