ESP8266 Community Forum

- Tue Oct 27, 2015 4:20 pm #32408 I'm having the same compiling error..

Any news?

- Tue Oct 27, 2015 8:56 pm #32424 Work around I used was to edit the installed DHT library to remove the computation from the computeHeatIndex() function.

In the Arduino install path ..\libraries\DHT folder edited DHT.cpp as follows:

Code: Select all//boolean isFahrenheit: True == Fahrenheit; False == Celcius
float DHT::computeHeatIndex(float temperature, float percentHumidity, bool isFahrenheit) {
//was something that used square root.... 
return -555;
}

This then compiled and ran fine on a ESP-01 to return temp and humidity.

- Fri Oct 30, 2015 5:42 am #32611 Thx a lot!

It is working perfectly.

Cheers

- Fri Jan 01, 2016 7:06 pm #37655 Ditto on the progress report.

I'm running into what I think is a similar issue with the Adafruit_TCS34725 color sensor. I'm pretty new to this stuff but I seem to be up against problems that are a bit beyond my control. It is really hard to tell what is my learning curve and what might be issues that could impact many people and should be addressed by developers. I've done quite a bit of setup just to get to this point. Getting the proper versions of board - library, etc. has taken a fair amount of work. I'm stuck on this. I have a feeling that if there is a fix, it will get far more than just me unstuck.

The error and sketch...

Here is the error message from the tcs34725 sample.
c:/users/tskunka.uofi/appdata/roaming/arduino15/packages/esp8266/tools/xtensa-lx106-elf-gcc/1.20.0-26-gb404fb9/bin/../lib/gcc/xtensa-lx106-elf/4.8.2/../../../../xtensa-lx106-elf/lib\libm.a(lib_a-e_pow.o):(.literal+0x100): undefined reference to `__ieee754_sqrt'
c:/users/tskunka.uofi/appdata/roaming/arduino15/packages/esp8266/tools/xtensa-lx106-elf-gcc/1.20.0-26-gb404fb9/bin/../lib/gcc/xtensa-lx106-elf/4.8.2/../../../../xtensa-lx106-elf/lib\libm.a(lib_a-e_pow.o): In function `__ieee754_pow':
d:\ivan\projects\arduinoesp\toolchain\dl\esp-newlib\build\xtensa-lx106-elf\newlib\libm\math/../../../../../newlib/libm/math/e_pow.c:164: undefined reference to `__ieee754_sqrt'
collect2.exe: error: ld returned 1 exit status
Error compiling.

Here is the sketch itself...
#include <Wire.h>
#include "Adafruit_TCS34725.h"

/* Example code for the Adafruit TCS34725 breakout library */

/* Connect SCL to analog 5
Connect SDA to analog 4
Connect VDD to 3.3V DC
Connect GROUND to common ground */

/* Initialise with default values (int time = 2.4ms, gain = 1x) */
// Adafruit_TCS34725 tcs = Adafruit_TCS34725();

/* Initialise with specific int time and gain values */
Adafruit_TCS34725 tcs = Adafruit_TCS34725(TCS34725_INTEGRATIONTIME_700MS, TCS34725_GAIN_1X);

void setup(void) {
Serial.begin(9600);

if (tcs.begin()) {
Serial.println("Found sensor");
} else {
Serial.println("No TCS34725 found ... check your connections");
while (1);
}

// Now we're ready to get readings!
}

void loop(void) {
uint16_t r, g, b, c, colorTemp, lux;

tcs.getRawData(&r, &g, &b, &c);
colorTemp = tcs.calculateColorTemperature(r, g, b);
lux = tcs.calculateLux(r, g, b);

Serial.print("Color Temp: "); Serial.print(colorTemp, DEC); Serial.print(" K - ");
Serial.print("Lux: "); Serial.print(lux, DEC); Serial.print(" - ");
Serial.print("R: "); Serial.print(r, DEC); Serial.print(" ");
Serial.print("G: "); Serial.print(g, DEC); Serial.print(" ");
Serial.print("B: "); Serial.print(b, DEC); Serial.print(" ");
Serial.print("C: "); Serial.print(c, DEC); Serial.print(" ");
Serial.println(" ");
}