Any chance you can draw this?  It would make it easier to see what you're suggesting.

Cheers ! Geoff

Hi,

Thanks for the interesting musings.  You got me thinking too...

unless i'm missing something here...  When in current regulation mode, it requires a low value resistor to get any kind of reasonable current?...
eg - To get a regulated 961.588ma of current, the Resistor has to be 1.3 ohms, and at least 1.5watts to cope.

That's certainly how I read it, and that's supported by a bit of google-fu too (for example this page)

So for each LM317, I might as well spend $10 on a 2watt potentiometer, just to get a steady current... I might as well just use 1.3ohm resistor
and omit the lm317 from the circuit all together!

I guess you could, but that would be a current that fluctuates with input voltage (a current limiter rather than a true regulator) so you'd still be adding some kind of voltage regulation.  Besides which by my maths the LM317T & a 5W 1 Ohm cement resistor is 42c all up (using as a reference pricing from my usual, Tayda for 5W 1ohm cement resistor and LM317T) so since LM317 comes in as a winner on cost, even if you use one for voltage and one for current, why would you choose the (comparatively expensive) 2W pot?  

And since your pot will be doing the current limiting directly in series with the load, wouldn't it run out of spec at 5V at 400mA (as an example) whereas at that LM317 can produce constant current at far higher voltages.  In the example linked above his LEDs had a 12V supply and consumed 320mA each - 3.84W which would let the smoke out of the 2W pot alternative - or am I missing something in your design?

(Zener Diode + Resistor anyone? = Almost CC/CV lol)

Can you get a constant current circuit from just those, or constant voltage only?

Cheers !
Geoff

Hi

A simple Zener diode voltage regulator might do the trick.  I punched the maximum values you mentioned into this online calculator and it appears a 14 Ohm resistor (so you'd use a 15R) along with the 3.6V Zener diode will cover it off nicely.  A very cheap solution too.

I'm not certain what will happen inside the 2V headroom they suggest for the voltage, so need to do more reading.  If that's a problem perhaps a potential divider with just two resistors will be more stable?

Cheers ! Geoff

Hi Bob

Great project.  Thanks again for sharing it.  Do you find you miss being able to wind the volume on your guitar back (or up) as you play with your little finger or side of your hand?  I like the idea of presets but wonder if I'd miss that fine control while playing.

Geoff

your logic is incorrect...

the purpose of the arduino is for ametures to get stuck in doing something similar to what the big companies do without the price tag...

if you saw 'arduino' on a nasa probe i might be a little concerned, 300 dollar radio equipment is no doubt fun, but it does not belong with an 8 bit chip...

Are you replying to this thread?  All the links here are for similar modules to what you originally asked about, not $300 items? 

If you're in response to my suggestion about a lack or acknowledgement - I only pointed that out as there are other inexpensive chipsets (eg nRF24L01+) that implement both transmit and receive in the one module so you implement feedback or a request mechanism for more robust comms. 

Cheers ! Geoff

Does this work on the newer IDE's ?

Sure does !

Hi,

They are quite inexpensive but you'll find there is quite a bit of info on them.  For example this page at Seeed has several links to tutorials etc and there's also this article which talks about extending the range.

The upside is they're very simple to use, and consume only one data pin at each end.  The downside of course is this has no feedback to the transmitter to acknowledge the transmission was received.

Cheers ! Geoff

Hi

That code will do the trick. And yes the 2nd resistor goes to GND so when the power is of your input pin is pulled low.

You may also need to debounce the returned value.  Lots of examples via Google-Fu on how to do that to get a reliable value read.

Cheers! Geoff

Hi,

To tell the Arduino your LEDs are on you can simply take that LED supply out to an Arduino digital input via a large current limiting resistor (say 10k). You can read that value via digitalRead() or read it as an interrupt.  That pin will also need a pulldown resistor to force a default 0 value.

Cheers! Geoff

Thanks hilukasz - I'd not seen this before, but your post saved a lot of my hair tonight I think.  It's not often I am doing both ATmega and ATtiny work simultaneously, but I am here and your explanation certainly makes sense based on my experience in the past hour.

Cheers ! Geoff

China?  No, Thailand.  And they're awesome fwiw

Fungus you are a champion.  It compiles in 1.01 etc now without an error.   I've also submitted this as an issue to the library author with a link here to your explanation.

Thanks ! Geoff

Hi fungus

The nearest thing I've found (and the only reference to the word virtual) doesn't use the virtual keyword

Code:

#if !defined(ARDUINO) || ARDUINO < 100
// empty implementation instead of pure virtual for older Arduino IDE
void TM16XX::sendChar(byte pos, byte data, boolean dot) {}
#endif

In the header there's this

Code:

  protected:
#if defined(ARDUINO) && ARDUINO >= 100
// pure virtual is NOT supported in older Arduino IDE
virtual void sendChar(byte pos, byte data, boolean dot) = 0;
#else
virtual void sendChar(byte pos, byte data, boolean dot);
#endif

From what you're saying above, should there be a corresponding #else definition in the cpp file for IDE versions 100+ that's missing?

Thanks
Geoff

Hi

I've been trying to use the TM1638 library (from https://code.google.com/p/tm1638-library/) with the ATtiny85, inspired by this instructible.  I'm using the arduino-tiny cores, not the MIT ones in that instructible.  What I'm finding is with any of the younger IDE versions I'm getting this error when I try to verify:

Code:

TM1638\TM16XX.cpp.o:(.rodata._ZTV6TM16XX+0x14): undefined reference to `__cxa_pure_virtual'

I've tried 1.0, 1.0.1 and 1.0.4; I've also tried the TM1638 libraries v2.0.1 (the version used in that instructible it appears) and the latest 2.1.3 but in all combinations of those that error occurs.

If I roll back to Arduino IDE 0022 it compiles though.  And that's with either library version.

Code:

Binary sketch size: 4042 bytes (of a 8192 byte maximum)

I'm using the code from the instructible, but the standard 2.1.3 example for TM1640 compiles okay also.

As a fallback I'll be completing this project in Arduino IDE0022, but it would be nice not to have to go retro.  Any ideas what this error is pointing to?

Thanks,
Geoff

Maybe a link to a dropbox folder or similar would work?