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1  Using Arduino / General Electronics / Re: WS2812B dissipation question on: July 24, 2014, 10:23:23 am
Quote
The best bet is to solder it onto very small squares of strip board and wire them up, before gluing them onto what you want.

Thank you!
2  Using Arduino / General Electronics / Re: WS2812B dissipation question on: July 24, 2014, 10:13:04 am
Thanks for suggestion!
3  Using Arduino / General Electronics / Re: WS2812B dissipation question on: July 24, 2014, 08:41:21 am
Thank you for reply.

I do not read anything about it in the datasheet i've found, that's the reason why i'm asking it here smiley

Quote
Can it be wired "on-fly",
I mean without mounting it on a pcb, simply soldering the chip.
For an experiment, I would like to mount the chip straigh on a plastic box, gluing it, but i suppose it is better to solder it on a pcb and then fix the pcb on the plastic box.
4  Using Arduino / General Electronics / WS2812B dissipation question on: July 24, 2014, 08:19:08 am
Hello,
I've never played with WS2812B, so i've a question.
I've seen some reseller that sells that chip solder on a pcb, to provide some dissipation, so, does this chip became hot? Can it be wired "on-fly", or does it need some sort of pcb heatsink?
thanks!
5  Using Arduino / Programming Questions / Re: MQ-135 Value Conversion on: May 08, 2014, 01:42:46 pm
thank! smiley-wink
6  Using Arduino / Programming Questions / Re: MQ-135 Value Conversion on: May 08, 2014, 03:02:55 am
yes i get this working.
this is the blog post speaking about how did i get it working, and how does it works.
http://davidegironi.blogspot.it/2014/01/cheap-co2-meter-using-mq135-sensor-with.html
7  Using Arduino / Programming Questions / Re: MQ-135 Value Conversion on: December 02, 2013, 08:09:26 am
i'm comparing it against a mh-z14 (using a xively datastrem).
it seams to words good also for Co2 (from 300 to 2000ppm)
results will be published soon on my blog (as soon as i will have time to write the post, and analyze graph).
8  Using Arduino / Sensors / Re: MPU-6050 gyro calibration on: June 17, 2013, 01:39:18 pm
pictures here are taken from processing.org (there is a mac version too).

for calibration, you can find the python script i've built here:
http://davidegironi.blogspot.it/2013/01/gyroscope-calibration-helper-01-for-avr.html
it should works on mac too smiley-wink
9  Using Arduino / Storage / Re: An eeprom config library for arduino on: March 18, 2013, 04:06:56 pm
on attiny85 you have to implement software uart, it could work but you have to try.
10  Using Arduino / Storage / An eeprom config library for arduino on: March 13, 2013, 06:03:58 am
Hello, i've just published this library, i hope it can help your developing.

AVR uartConfig is a small footprint library you can use to config your arduino eeprom through uart communication.
AVR uartConfig is a set of tools running on Windows, Linux and Mac, made up or:
* a avrgcc firmware library
* a commandline utility
* a gui tool

This library prevent you to wire up a disply and buttons to configure your micro eeprom. For example is it usefull to setup PID parameters of your robot by uart/bluetooth uart, or for other small devices that doesn't came with an output/input interface.

more information and download here: http://davidegironi.blogspot.it/2013/03/avr-uartconfig-atmega-and-arduino.html
11  Using Arduino / General Electronics / Re: Circuit check for noob on: January 31, 2013, 08:58:58 am
I think the best option is to run that detector (both the amplifier side and the LED side) from a regulated 5V supply. However, the readings you are getting appear to be roughly ratiometric with the supply voltage. Therefore, if you feed the output into in analog input of an Arduino that is powered from the same 5V supply, then the ADC will approximately compensate for supply voltage variation.

thank for reply,
my readings are taken from arduino, and checked with multimeter, to get voltage i use bandgap for the adc ref voltage, so it does not compensate reading. to check adc i try the compensation why different voltage using other sensor, or using a simple resistor, and it works!, but this times not; i think is the output of this sensor that change with voltage supply changing, but datasheet unfortunately do not tell anything about sensitivity over voltage.
anyway, i suppose you are right, best option is to run it over regulated 5v power.
12  Using Arduino / General Electronics / Re: Circuit check for noob on: January 31, 2013, 05:36:24 am
hello,
i’m experimenting too with GP2Y1010AU0F, but i’ve found a strange behaviour.
my sensor is conncted like datasheet explain, pin 3 direct to atmega (i’ve also try using a mosfet but it do not change)
if i run GP2Y1010AU0F with 5.330 voltage i read an output voltage between 0.800 and 0.850
if i run GP2Y1010AU0F with 5.080 voltage i read an output voltage between 0.770 and 0.830
if i run GP2Y1010AU0F with 4.670 voltage i read an output voltage between 0.700 to 0.770
so there’s a small drift when supply voltage change.
i suppose the fig 3 of datasheet, from which we can extract slope and offset to find dust sensity, it’s 5.0v supply voltage, so reading an “incorrect” voltage would bring to incorrect mg/m^3 conversion.
have you also find this behevior?
have you find a way to balance the supply voltage drift?

thanks all
13  Using Arduino / Programming Questions / Re: MQ-135 Value Conversion on: January 16, 2013, 01:24:42 pm
Quote
so i can obtain Ro value for the chip in open air.
can this be right?
Assuming you're not in Bejing with the current smog levels the answer is yes.

i hope here near milan is not so high smiley
even if i can know it with precision i will approximate it to 394
14  Using Arduino / Programming Questions / Re: MQ-135 Value Conversion on: January 16, 2013, 10:55:59 am
i've made a mistake before, i consider Rs/Ro = ppm, but from fig.2 of datasheet is not so.
it seems that it is a power function (see attached).
so i made some power regression based on the values, and i obtain a scaling factor and an exponent
given those values
a = scaling factor obtained by datasheet figure, for the gas you need
b = exponent obtained by datasheet figure, for the gas you need
ppm = a*(Rs/Ro)^b
now, to obtain a valid Ro value, we have to know the ppm of a gas, for C02, we know the CO2 value for atmosphere,
http://www.esrl.noaa.gov/gmd/ccgg/trends/#mlo
so i can obtain Ro value for the chip in open air.

can this be right?
15  Using Arduino / Programming Questions / Re: MQ-135 Value Conversion on: January 16, 2013, 09:47:29 am
yes, i've read the information you link.
but the key point is to find a valid Ro, i do not have a calibrated sensor, so i ask you if someone can tell me a valid Ro values for this chip.

thanks
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