DigiSpark with gps, flow sensor & display?

[aidave]

Originally, I had planned on using a teensy board for this project, but someone suggested the digispark  (smaller/less expensive)

What would a good lcd display (12+ characters) to use, considering I'll be reading a gps and a flow sensor?  (and: will the digispark handle 2 sensors (gps/flow) and lcd w/o a problem?)

Also; the values read from both sensors need to survive a power cycle, would I need additional flash or sd memory?

Thank you

[MichaelMeissner]

The digispark does have a 16x2 lcd shield(using an i2c lcd): http://digistump.com/products/16

In terms of gps support, it depends on the gps.  If the gps supports i2c, you can daisy chain both the lcd and the gps on the i2c bus.  Note, the digispark runs at 5v, so you need to make sure the gps can handle 5v.  Alternatively if the gps uses serial I/O, it is somewhat harder, in that the digispark does not have hardware serial support.  There is a software serial driver, that I've seen people talk about.

I don't know anything about flow meters, but if it uses analog, there is an analog pin (#5) that is available, even if you are using i2c (which uses pins 0/2, and 2 is the 2nd analog pin).  There are i2c analog->digital chips if you find you need more analog devices.

if both the gps and flow meter are serial devices, I believe the software serial library has a warning that it only supports one input at a time.

In terms of saving state, you have 512 bytes of EEPROM on the digispark that you can use to store stuff and it is not reset when the device is powered on.  If that is not enough, there is an eeprom shield that should give you 32K of extra memory: http://digistump.com/products/28

I'm not sure if the digispark has enough resources to drive a SD drive.

[Bluebie]

Digispark can talk to SD cards, but it takes about 2-4kb of memory, and there's only 6kb all up, so for a project so complex I think you would be better off with the teensy.