MySensors on ATTINY85

[vtento]

I choose ATTINY85 becaus I would like develop a sensor Network small, cheap and easy to make.
But using an Attiny micro I meet a lot of problem with memory space ....
For example when I using a DS12B20 temperature sensor I should send value
without conver in Celsius degrees (I can't divide by 16).
I would like undestaind how many space use the Arduino bootloader in an Attiny chip
Thanks

[hek]

Wow, you got it running on ATTINY85! .

You could probably strip down the library a few extra bytes by removing all routing functionality.

[vtento]

I have already taken done to cut any library where possible (serial debug, utility / LowPower) I have already rewrite interrup WDT for sleep mode and pin change...
Now I can only hope to take some byte from the arduino bootloader, but I don't know how?

[hek]

@vtento

Pretty hardcore.

Afraid I can't help you much on the bootloader. Which arduino bootloader are you using. I imagine there are a few out there.

[hek]

Is there enough pins to even connect the radio? Adding one wire on top of this? How did you do it?

[vtento]

[vtento]

I share MOSI with 1-WIRE bus, I put in sleep mode the radio, then I read the sensor and after I send the value...
Unfortunately I can't use only 3 pin for the radio module because I work with a botton battery (I can't swith off) and I need TX and RX

[axillent]

@vtento cool work!

make sure to avoid floating numbers. also try to not use 32 bit numbers and limit usage of 16 bit numbers
division by 16 is better to do by >> right shift

DS18B20 code can be shrinked up to 400-500 bytes while some in examples it is eating 1-2k

[tekka]

@vtento said:

I have already taken done to cut any library where possible (serial debug, utility / LowPower) I have already rewrite interrup WDT for sleep mode and pin change...
Now I can only hope to take some byte from the arduino bootloader, but I don't know how?

Due to space constraints, I would omit the booloader and use the entire space for the sketch. However, the smallest bootloader is 0.5kb (Optiboot) and if OTA updates are important, then MYSBootloader (2kb). That said, it all depends how much you manage to squeeze the library code.

[Joseph Macaulay]

Hi, can you share any of the source code you got running on the ATTiny85? I've got 5 ATTiny85s & 5 ATTiny84s. I've been running the TMRH20 RF24, Network, and Mesh on them, but I wanted to see if I can use the MySensor stuff. Thanks!

[axillent]

@Joseph-Macaulay the version of RF24 is comming with latest MySensor contains a software SPI driver able to work on tiny MCU

[vtento]

• @Joseph-Macaulay Hi, this is the sketch that I use for Themp sensor

MySensors85.ino

[mrendu43]

hello
I dont understand why didnt you use reset, and delcare it as input pin?
as i know it can be declared as io

[Sweebee]

Oitzu and I (testing :P) are currently working on the Attiny support. To test you can download this library (the same as the original one except that it includes the attiny).

Its working so far.

Bugs:
Your node id is the same as child id (if you set a different child id, somehow the attiny ignores it and makes it the same as your node id).
Sleep is working with interrupt but it does the setup again after wake.
Sleep / timer is not yet working.

library: https://github.com/Oitzu/Arduino/tree/master/libraries/MySensors (You can replace it with your existing mysensors library)
example sketch thats working: http://pastebin.com/xRu2JNQ9

wiring:

                  +-\/-+
                 1|o   |8  VCC/CE  RED/ORANGE
 YELLOW  CSN     2|    |7  SCK     GREEN
 -       SENSOR  3|    |6  MOSI    BLUE
BLACK    GND     4|    |5  MISO    VIOLET
                  +----+

[Andy]

Awsome work Oitzu and Sweebee!

Just tried it out and it works perfect :)

Have you succeeded with getting the sleep/timer working? I've tried but discovered that my skills aren't good enough.

[Sweebee]

Not yet. Maybe next week. To much work at school right now ^^. But when it works i'll post it here.

[Andy]

@Sweebee Got it working last night (I hope!), I haven't measured the power consumption yet.

It doesn't have the resolution of ms. To save battery the attiny85 will sleep for 8 seconds, then wake up and go to sleep again. So if you call gw.deep_sleep(7), it will sleep fox 7x8=56 seconds. It is possible to get a more precise timer by calculating the best combination of sleep timers. For example if you want to sleep a minute, sleep 7x8s=56s and then an additional 1x4s=4, total 60s.

It needs some cleaning up and correct naming/commenting/testing e.t.c.

void MySensor::deep_sleep(int time) {
	// Sleep alternatives:
	// 0=16ms, 1=32ms,2=64ms,3=128ms,4=250ms,5=500ms, 6=1 sec,7=2 sec, 8=4 sec, 9= 8sec
	int ii = 9;	// sleep 8 seconds at a time.
	byte bb;
	int ww;
	if (ii > 9 ) ii=9;
	bb=ii & 7;
	if (ii > 7) bb|= (1<<5);
	bb|= (1<<WDCE);
	ww=bb;

	MCUSR &= ~(1<<WDRF);
	// start timed sequence
	WDTCR |= (1<<WDCE) | (1<<WDE);
	// set new watchdog timeout value
	WDTCR = bb;
	WDTCR |= _BV(WDIE);
  
	// Count some sheeps.
	for(int i=0;i<time;i++) {
		RF24::powerDown();	
		cbi(ADCSRA,ADEN);                    // switch Analog to Digitalconverter OFF
		set_sleep_mode(SLEEP_MODE_PWR_DOWN); // sleep mode is set here
		sleep_enable();
		sleep_mode();                        // System actually sleeps here
		sleep_disable();                     // System continues execution here when watchdog timed out   
		sbi(ADCSRA,ADEN);                    // switch Analog to Digitalconverter ON
	}
}

[n3ro]

has someone tested digispark? That would be to test a lot easier.

http://digistump.com/products/1

[mntlvr]

@Andy said:

Awsome work Oitzu and Sweebee!

Just tried it out and it works perfect :)

Have you succeeded with getting the sleep/timer working? I've tried but discovered that my skills aren't good enough.

Hi Fella,
I just came across this post several weeks ago , I was looking for a smaller cheaper way of making a binary switch to use with my Veras. After reading the "Great debates" whether an ATTiny 85 could be used for such a purpose, I decide to try what was here and by the individuals who said they had made them work. I built one and powered it with a Li-Ion 3.7 v 4000 Mah battery. I have had it in use now for about a week and so far it works great. I have not been able to make the WDT work but from my test so far , running the ATTiny and nRF24l01+ from a Li-ION 4000 Mah battery , it should last for months. Now the the entire circuit is drawing 6.0 ma and when tripped the unit drew 7.5 ma. Now I am sure the current was higher than 7.5 ma when in transmit but it would be for just a very small amount of time. Thanks for the leg work you guys did to make this project for me happen.

[ted]

@Sweebee
Do you mind sharing your library again? The link is no longer working.