.from: http://www.frank-zhao.com/thingspeak_mbed_tut1/
#include "mbed.h"
#include "EthernetNetIf.h"
#include "NTPClient.h"
#include "HTTPClient.h"
// networking stuff
EthernetNetIf eth;
NTPClient ntp;
HTTPClient http;
char* ntpServerUrl = "0.ca.pool.ntp.org";
char* thingSpeakUrl = "http://api.thingspeak.com/update";
char* thingSpeakKey = "IS6YCLKIR423VO5H";
char urlBuffer[256];
char timeBuffer[64];
// pin defs
DigitalOut rst(p30);
DigitalOut clk(p29);
DigitalInOut dq(p28);
void DS1620Send(long data, int numOfBits)
{
dq.output(); // we are sending
for (int i = 0; i < numOfBits; i++)
{
clk = 0;
wait_us(0.05);
if (data & (1 << i)) // bit is 1
{
dq = 1;
}
else // bit is 0
{
dq = 0;
}
wait_us(0.5);
clk = 1;
wait_us(0.5);
}
dq.input(); // go back to being input
clk = 1; // leave high
}
float DS1620ReadTemp()
{
rst = 1;
DS1620Send(0xAA, 8); // read temp command
dq.input();
int results = 0;
// read in 9 bits
for (int i = 0; i < 9; i++)
{
clk = 0;
wait_us(0.5);
clk = 1;
wait_us(0.05);
if (dq.read() != 0) // bit is 1
{
if (i < 8)
{
results |= 1 << i;
}
else
{
results *= -1; // last bit is sign bit
}
}
wait_us(0.4);
}
clk = 1; // leave high
rst = 0;
return (float)results / 2; // div by 2 since last bit is 0.5
}
void DS1620Setup()
{
// initial pin states
rst = 0;
clk = 1;
dq.input();
wait(0.1);
rst = 1;
DS1620Send(0x0A0C, 16); // config for continuous mode with CPU mode
rst = 0;
wait(0.1);
rst = 1;
DS1620Send(0xEE, 8); // start continuous conversions
rst = 0;
wait(0.1);
}
int main() {
printf("Start\r\n");
printf("Setting up Ethernet...\r\n");
EthernetErr ethErr = eth.setup();
if(ethErr)
{
printf("Error %d in ethernet setup.\r\n", ethErr);
return -1;
}
printf("Ethernet setup OK\r\n");
// get time from ntp
time_t ctTime;
Host server(IpAddr(), 123, ntpServerUrl);
ntp.setTime(server);
// start the sensor
DS1620Setup();
while(1)
{
// update data here
ctTime = time(NULL);
float temperature = DS1620ReadTemp();
// format time here
timeBuffer[0] = 0;
strftime(timeBuffer, 64, "%Y-%m-%d %H:%M:%S", localtime(&ctTime));
// for debug
printf("Time: %s, Temperature: %f\r\n", timeBuffer, temperature);
// format url here
urlBuffer[0] = 0;
sprintf(urlBuffer, "%s?key=%s&field1=%s&field2=%f", thingSpeakUrl, thingSpeakKey, timeBuffer, temperature);
printf("Request to %s\r\n", urlBuffer);
HTTPText resp;
HTTPResult res = http.get(urlBuffer, &resp);
if (res == HTTP_OK)
{
printf("Result :\"%s\"\r\n", resp.gets());
}
else
{
printf("Error %d\r\n", res);
}
wait(16); // limited by ThingSpeak's API
}
return 0;
}
