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151  Using Arduino / Project Guidance / [Solved]using robs dht11 library c to f conversion is this the best way? on: January 17, 2013, 02:27:50 pm
is this the easiest/best way to do C to Farenheit conversions?

Serial.print(DHT.humidity, 1);
  Serial.println(DHT.temperature*1.8+32, 1);

also, storing each in eeprom, will one byte hold the data? say 76.1? best way to do that would be appreciated thanks!

solution. changed
for the whole number. the first one gives a one place decimal point. moral of story, i learned a bit more by reading around. thank you all. kudos to rob for library, i couldnt use the dht22 library couldnt figure out conversion for life of me. this is small and compact, keep up good work you arduino folks.
152  Using Arduino / Storage / rtc spi help 1305 and 1302 3wire also epoch on: January 16, 2013, 02:22:04 pm
greetings. i have available 1302 and 1305(of which i would like to use 1305). i looked through the posts here and found this     but i dont understand exactly whats going on in some parts. the code im trying to use works on other spi devices and im not getting anything on the 1305 ive setup. ive tied SERMODE to +5 to indicate spi mode, vice 3wire, and grounded all unused power pins as per the datasheet. i know these are old parts but im not able to get a 1307 or any other rtc for that matter. i need to use what i have. plus im having trouble with i2c which is another topic.

#include <SPI.h>
#define ss 10//ss

void setup() {
  byte r=SPI.transfer(0);
  Serial.println(r, BIN);
  void loop() {

i get a 128 returned from this. ive tried the code from the other post with the suggested fixes and get nada also. any insight? or better yet anyone have a simple to understand sketch, either transfering one byte at a time or burst mode read with lots of comments. thank you. also with the 1302 which i would use, im not understanding the read, of which im sure is the simplest thing im missing. i would like to move on to other sensors, but an rtc is paramount i think in any project. my robot will never take over the world if he cant at least tell time.

also interested in using epoch to store timestamp, i see alot of posts using this method, some suggestions from ppl, but no real instructions on setting it up and executing it. thank you.
153  Using Arduino / Displays / Re: BPP-420 s.e.e. LCD on: January 06, 2013, 11:09:29 am
good idea on the title don thx, and yes i did misspell helllo lol.
154  Using Arduino / Displays / How to use the Parallax / Scott Edwards serial LCD backpack on: January 04, 2013, 11:22:14 am
this works (tested) with other scott edwards electronics backpack serial LCD's. I purchased these years ago from parallax. had them laying around, now i can use them. also, to send functions ie clear screen etc, myserial.write(12); <-- clr screen for bpp-420. sorry forgot to include that in the code. i dont believe the delays are needed in some cases, you will have to experiment a bit.

/*code to control BPP-420 Scott Edwards Elec. LCD. */

#include <SoftwareSerial.h>

#define rxpin 10
#define txpin 11
#define inverted 1

void setup() {
 SoftwareSerial myserial(rxpin, txpin, inverted);

  digitalWrite(txpin, LOW);
  pinMode(txpin, OUTPUT);

void loop(){
155  Using Arduino / Sensors / Re: Mpx4115 pressure sensor solution on: January 02, 2013, 11:46:55 am
relax, just lil snippet to test/get sensor working. just trying to help someone since there is very little information on this sensor that I can find.
156  Using Arduino / Project Guidance / Re: Buying assistance on: January 02, 2013, 11:04:31 am
arduino and ultrasonic range finder thing everyone uses i guess.. total solution for rangefinding for less than 50 if you include sensor and some other stuff i guess. sensor is hc-sr04.

// ---------------------------------------------------------------------------
// Example NewPing library sketch that does a ping about 20 times per second.
// ---------------------------------------------------------------------------

#include <NewPing.h>

#define TRIGGER_PIN  12  // Arduino pin tied to trigger pin on the ultrasonic sensor.
#define ECHO_PIN     11  // Arduino pin tied to echo pin on the ultrasonic sensor.
#define MAX_DISTANCE 200 // Maximum distance we want to ping for (in centimeters). Maximum sensor distance is rated at 400-500cm.

NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); // NewPing setup of pins and maximum distance.

void setup() {
  Serial.begin(115200); // Open serial monitor at 115200 baud to see ping results.

void loop() {
  delay(50);                      // Wait 50ms between pings (about 20 pings/sec). 29ms should be the shortest delay between pings.
  unsigned int uS =; // Send ping, get ping time in microseconds (uS).
  Serial.print("Ping: ");
  Serial.print(uS / US_ROUNDTRIP_IN); // Convert ping time to distance and print result (0 = outside set distance range, no ping echo)
  Serial.println(" inches");
157  Using Arduino / Sensors / Mpx4115 pressure sensor solution on: January 02, 2013, 10:57:41 am
hi. sensor works great just thought i'd share.

the math to convert to kPa and psi.


b = ((a * .0049 / 5) + .095) / .009;//conversion to kilopascal kpa  << this is all i wanted to show

regular around sealevel pressure is around 101.xx kpa and 14.xx psi.
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