Hi,
can I ask you a c-beginners question?
I have problems with my time structure. This is basicly my code:
void function_1();
void function_2();
struct tm *tmp;
char LCDTime[20];
void setup() {
...setup stuff
}
void loop() {
function_1();
function_2();
delay (1000);
}
void function_1(){
time_t now = time(nullptr);
tm *tmp = localtime(&now);
sprintf (LCDTime, "%02d:%02d:%02d", tmp->tm_hour , tmp->tm_min, tmp->tm_sec);
DEBUG.println (tmp->tm_sec);
}
void function_2(){
DEBUG.println (LCDTime);
DEBUG.println (tmp->tm_sec); // <---------------------- causing wdt reset!!!!!!
}problem is the line " DEBUG.println (tmp->tm_sec); " In function_1() its working w/o problem
How can I use the elements of the structure tmp in function_2()?
It'll have to be global, i.e. Defined outside scope of fn1 or made static and pass a pointer to fn2
tm in function_1() overides global tm
scope problem
+1 @Palatis
But I defined it outside the function!? (see line 3)
@brutzler remove tm in
tm *tmp = localtime(&now); in function_1()
that is the redefinition of tmp
and if you want it to work on global scope, put
time_t now global
@mozgy redefinition: ok. But do I need to put 'time_t now' global? I want to access the struct (tmp) and its elements in the other function?
Perhaps I think wrong, with my poor C-experience....
Perhaps I think wrong, with my poor C-experience....
@brutzler that
time_t now = time(nullptr); inside f1 is variable allocation and scope only inside that function
does anyone know if there is any way of resetting whatever calibration data the SDK saves in the latest sdks, without using eraseConfig that actually wipes the flash ?
the purpose being to be able to reset calibration data and so on (is possible without removing ssid and pass) and make sure this calibration reset is active, without having to restart the module...
@mozgy : OK, I thought the
Then this way?
tm *tmp = localtime(&now) is a function, that allocates the actual time to the struct...Then this way?
tm *tmp = localtime(&now)remove from function_1- and
struct tm *tmp = localtime(&now)as global declaration for line 3?
it is
it doesn't allocate anything... please check http://www.cplusplus.com/reference/ctime/localtime/
@mozgy thx. will try this in the evening when @home
but life of that 'tmp' variable is only inside f1()
@igrr actually it does allocate space for '*tmp' pointer :)
@mozgy: then I can not use the
tmp->tm_sec in function_2??
correct
hence crash
no step further then.... ;-(
my aim is this:
call f1() every second. And use the actual values for sec/min/hour.... in f2().
As the values are stored in the structure, I thought easiest is to use the struct in f2() too.....
call f1() every second. And use the actual values for sec/min/hour.... in f2().
As the values are stored in the structure, I thought easiest is to use the struct in f2() too.....
@igrr while we're on subject - dst is still not implemented ?
no, and i don't think we even have an issue open regarding that
And what about this way?
struct tm *tmpas global declaration for line 3?tmp = localtime(&now); in fc1()
pointer and references are not my favourite. (and a lot of other things in C/C++ too) LOL
nope, still a bit wrong
struct tm tmp as a global var
you need whole variable available global, not just pointer to somewhere
recheck that link that igrr linked
Hmmm...
*tmp = localtime(&now); in fc1()? Sorry I can only guess....
hey guys
i got an LM75A sensor and it's doing I2C. I've never worked with I2C before, how do you connect and read data from it?
@skorokithakis you simply needs to use 2 pins on ESP and provide PullUp on those, and then use Wire library. Personally, since both GPIO2/GPIO0 needs pullups too, those pins are perfect for I2C bus.
@skorokithakis default pins are 4,5 btw https://github.com/esp8266/Arduino/blob/573a0fb47fc0dc6dc25010d50642494dbb069476/variants/ESPDuino/pins_arduino.h#L36
ah, thanks guys. do i connect SDA to SDA, or SDA to SCL, like TX/RX?
yes
which? :smile:
first one
thanks
sda to SDA
@martinayotte by the way, why does this need a pullup?
I2C is driven with OpenDrain signal, so the Master should have PullUps
ah, i see, thank you
welcome
oh man, nick gammon
i remember him from 1996
oh, nice page, thank you
Wire.begin(4, 5);
twi_setClock(400000);
twi_setClock(400000);
max 450K
nah ESP goes upto 700K
yeah but could be limited by the slave
if thats what you mean
read me say 450k. Thanks. I will test.
bah, i need to break this thing out and have no idea how
it's pretty small
Oh, If cpu clock is 160M, 700K
80M --> 450K
i'm making a pcb and trying to decide whether to use this http://www.ebay.com/itm/Mini-DHT11-Temperature-and-Relative-Humidity-Sensor-Module-for-arduino-Best-/361446238396?hash=item5427dfe8bc:g:FPIAAOSwjVVVyJnc or the LM75
I think not using the core can make it go to 1MHz, but not sure
was just trying to make this as smooth as possible
dht22 please
expensive but accuracy/precision is better
dht11 is very .. very .. unprecise
well precision is in the specs 1 degree vs 0.1 degree,
accuracy is the weak point
either of them can go a bit wrong depending on power supply and pull-ups
even that 1C is questionable
- dht22 : temp(± 1, -40 ~ 80), RH(± 3%, 0 ~ 99.9%RH), kind of 1 wire, 3$, 2sec data interval, 3~4ms response, 1 device per gpio.
- ds18b20 : temp(± 0.5), -55°C to +125°C, 1 wire, waterproof, 1$, 93.75ms(9bit) ~ 750ms(12bit) response, many daisy chained devices per gpio.
- Si7021 : temp(±0.4 °C (max), –10 to 85 °C), RH(± 3% RH (max), 0–80% RH), –40 to +125 °C, 3$, i2c, 1 device per 2 gpio
my dht11 graphs are jigsaw ..
i wonder how much better bmp180 is
its smaller and uh looks better
just got bmp180 recently, haven't had time to tinker with it yet
but, so far 18b20 works nicely for me
yeah if you dont need humidity there are better options
compard to dht i mean
I need hmdty only on few places ..
yeah, the dht11 is wildly inaccurate, i've found
Si7021 has 22ms conversion delay.
is the LM75 better than the DHT22?
+2°C, 300ms conversion time.
which one?
LM75
dht, lm75 need over 3V.
From MAXIM specs : 3.0V to 5.5V Supply Voltage
hmm, i'm confused
does the DHT11 use LM75?
LM75 is two wire.
dht is 1 wire
oh LM75 has +-2 C error
that's useless!
i might as well cancel all those and get the DHT22
If you use battery, don't. use dht.
i use power, but the DHT22 seems better than the LM75 or the DHT11
Check 2 wire Si7021.
ah, thanks
There is also SA56004 providing both internal and remote external
@martinayotte Thank you.
but accuracy trade off : +-1C
SA56004 has alert pin !!
and T_CRIT for fan control.
Yes, along with fan
But no I2C address :-(
:(
Only one per bus
although can be hacked using a mux
up to 8 with 8 device type :( 5.4$
Can you connect multiple devices to the I2C bus?
Yes, If all devices have different address.
Of course, depending if device has address pins, like LM75, 8 possible devices
And the address is per type of device? So all LM75AD sensors have the same address?
Oh I see. That sounds great
i2c looks pretty useful, now i wonder why not all devices use it
What do you mean ? I'm using it in almost any design, not only ESP
well the LM75 is the first peripheral i've seen that uses it
but i guess i don't really use complicated peripherals
Do you want some new purchase list ? :-) MCP23017 16 GPIOS, MCP3021 ADC ... and many more :-)
esp - i2s - mini
i2c
Need a I2C MUX ? PCA9547 ! :-)
!! 8ch 2$ wow
Hardware PWM for RGB ? PCA9685 ! ;-)
hahaha nooooooooo martin
Dual UART to I2C ? SC16IS752 ! :-)
Unfortunately, not all of those are cheap, and not always available on eBay or Ali
16ch 12bit PWM/Servo Drive shield 4$. SC16IS752 Breakout 13$. PCA9547, SC16IS752 and PCA9685 are added to collection.:)
;-)
I dig my datasheets folder a bit more : Oh ! another Temp we didn't mentioned earlier, +-0.5C with I2C address pins : MCP9808
Another one +-0.25C : MCP9804
@martinayotte oh i think that's the free sample i got!
let me check
6 channels 18bits ADC : MCP3903
yeah, that's the one
it's tiny though
Some small DACs : MCP4725 and MCP4726
Some RTCs : PCF8563 or PCF85263 with RAM
you re like an encyclopedia of parts and references … are you a bot?
their MCP counterparts : MCP7940 and MCP79410
Oupps ! Time to go diner ... :-)
Simply that I love I2C (and SPI also, but a bit less), I didn't try all those ...
:P
bon apetit
and when you re back, on the off chance that in that huge database of stuff you must have, there is some list of various parts an components a newbie should order to have in his toolkit, i m sure a lot of us would appreciate it :P
(diner in the oven) ... Unfortunately, I don't have such database, it is only a folder with tons of PDF, I had to open them to remember what they are and share it previously and spontaneously ;-)
@tzapu i guess that'd be different for every newbie
the things i use most often is resistors, smd and throughhole, definitely AO3400 mosfets, capacitors
got resistors, caps in both forms
need to get some mosfets and learn to use them as well :P
This message was deleted
MOSFETs ? My choice are usually AO3401 and AO3402 (P and N) for current up to 4A. Some others in TO-220, like discussed several weeks ago with skorokithakis.
i was just wondering, if you were to purchase a few of each, what would be the most used to have, in this area of 3.3 driven µC s and such
cool, thanks for the hint @martinayotte
I only use 10k resistors and 22 uf capacitors at the moment
because those capacitors are the highest you can get in smd form
thanks, now my dinner is ready :P
and AO3402 mosfets have finally solved my "damn voltage driving" problem, as @martinayotte said
100 mosfets for 3$ nice
:P
yeah, get some breakout boards as well
you know what
thanks, will do
@skorokithakis for 22uF cap, you means the biggest in 0805, but look at 1206, you can find some 47uF, not as cheap, but perfect for ESP beasts
@martinayotte oh, good idea! let me look
@skorokithakis , I've received my SPX3819 few days ago from "slow boat"
is it not great?
I didn't try them yet ... But I presume they are fine
i love it
@skorokithakis thanks, saw your page before
im going to try to use one of those insanely cheap hx711 boards to read a relly low level analog signal
i was even wondering when in the owrld you have the time to do all the stuff on your blog and work and chat here and so on
:P
maybe it will work, but hardly any info available for hx711
@skorokithakis , yes, it looks the price is the same that I got, a bit expensive, but it is only to be use for ESP beasts, so 10 cents/each is not that bad
@tzapu haha, i wonder the same
@tzapu i updated the shopping list at the bottom now, though
@martinayotte yeah exactly, 10c per board is fine
CRAP
@skorokithakis can t see a list, cache maybe?
ebay spam started again ? :(
@mozgy hahaha yess
@tzapu just refresh
:)) yup
ah there it is, thanks, that should be usefull :D
there goes the stuff into cart .. :)
the only problem is that these things tend to go away
half my ebay shopping list isn't there any more
it's just 404s
there's always 'similar item' clicky
i guess it s really worth keeping a log of various stuff you buy, for instance, now your list is quite usefull for me ..
@mozgy does that work on 404ing pages?
only on ebay and not always
i really need to impose myself a limit, like 10e per ebay electronics shopping spree
otherwise it will never end
@tzapu heheheh
until the account is empty as well :))
@tzapu 10 euros is way too much
for me it's like 3 euros per order, always
worth having both n channel and p channel mosfets?
it';s just that i make 30 orders :smile:
@tzapu i only use n
well, not per order, per day like this :))
yeah, that s the problem with per order :))
@skorokithakis , in your page the AO3402 is mistakingly typed ...
nice, just received http://www.ebay.com/itm/391155625165
should simplify few PCBs
@martinayotte oops, thanks, fingers on wrong keys
@tzapu , yes, the AO3401 is P and AO3402 is N
@mozgy is that 4 10k resistors in one?
yep
that s so cool
now if @skorokithakis would make a version of his breakout that uses those as well … :sparkles:
kidding, it looks cool though
@tzapu which one?
http://www.ebay.com/itm/391155625165 on the tiny breakout
noooooooooooo, this exists?!
fiiiine :(
:))
heheh
Those SMT Res Net can be useful. Thanks ! I will order some
way ahead of you :smile:
yw ya@all :)
bloody hell, 3 click and i m over my imposed ordder budget
ahaha
just accept it, @tzapu
yeah..
@tzapu , simply borrow from tomorrow budget ;-)
yep, that's when martin gets here and we all chipin :)
@martinayotte that network is also compatible with 0805, right?
:)))))))
just harder to solder the 0805 close by
@skorokithakis , I don't think so, but I'm sure some 0805 exist too
please, no more parts today, i ll be back in a week with the same question so we can resume the ordering party :))
I will search for some octal resnet too
is that one resistor? wth
eh, never mind then :smile:
what do you mean ?
0805 network is expensive
1$ for 1 smd
Oh ! I didn't notice qty ... :-( better search again with other seller
only small value ones seem to be multiples
Otherwise, the one from @tzapu with 20x qty, even if 1206, still better
maybe it s a typo
as these are 100 of em..
Yes, just saw that from 2 vendors, although 2K2 is less useful, they are cheap
- shipping though
but still cheap
i m just gonna get the 1206 for now..
cheap is cheap :P
thanks everyone
although i m not sure if you are not my financial s security's most evil nemesis
This message was deleted
bollox...
ah
it s not a network though
that's not array
Oupps ! my bad ...
I didn't even zoom the picture
this is tho :D
what in the world is wrong with you ...
:P
well, i ve got 20 on the way now, i ll worry when i use at least 10.. :P
Oh ! some 0603 in qty 500 : http://www.ebay.com/itm/500PCS-SMD-0603-8P-10K-Thick-Film-Chip-Resistor-Network-Array-5-/181951081976
sooo smallll
sooo many
way too small
Yes, we can do some tapestry art with them ;-P