DFRobot GSM / GPS shield with UNO init error

Question

Apologies, but I have little experience of Arduino etc. Has the "Sim808 init error" been resolved anywhere please? I have tried every example I can find including the ones on these StackExchange pages without success. I started with the GPS test code from:

https://wiki.dfrobot.com/SIM808_GPS_GPRS_GSM_Shield_SKU__TEL0097

Parancey, Marcello, Pooya and Arslan and others have suggested mods to this code so I have tried all of them I think - none working.

Then I watched this video:

https://www.youtube.com/watch?v=fN8fwX3KmsM

which appears to show the code below or similar:

/*
### Get GPS data
1. This example is used to test SIM808 GPS/GPRS/GSM Shield's reading GPS data.
2. Open the SIM808_GetGPS example or copy these code to your project
3. Download and dial the function switch to Arduino
4. open serial helper
4. Place it outside, waiting for a few minutes and then it will send GPS data to serial
create on 2016年09月23日, version: 1.0
by jason
*/
#include <DFRobot_sim808.h>
#include <SoftwareSerial.h>
//#define PIN_TX 10
//#define PIN_RX 11
//SoftwareSerial mySerial(PIN_TX,PIN_RX);
//DFRobot_SIM808 sim808(&mySerial);//Connect RX,TX,PWR,
DFRobot_SIM808 sim808(&Serial);
void setup() {
 //mySerial.begin(9600);
 Serial.begin(9600);
 //******** Initialize sim808 module *************
 //while(!sim808.init()) { 
 while(!sim808.checkPowerUp()) {
 delay(1000);
 Serial.print("Sim808 init error\r\n");
 }
 //************* Turn on the GPS power************
 if( sim808.attachGPS())
 Serial.println("Open the GPS power success");
 else 
 Serial.println("Open the GPS power failure");
 
}
void loop() {
 //************** Get GPS data *******************
 if (sim808.getGPS()) {
 Serial.print(sim808.GPSdata.year);
 Serial.print("/");
 Serial.print(sim808.GPSdata.month);
 Serial.print("/");
 Serial.print(sim808.GPSdata.day);
 Serial.print(" ");
 Serial.print(sim808.GPSdata.hour);
 Serial.print(":");
 Serial.print(sim808.GPSdata.minute);
 Serial.print(":");
 Serial.print(sim808.GPSdata.second);
 Serial.print(":");
 Serial.println(sim808.GPSdata.centisecond);
 
 Serial.print("latitude :");
 Serial.println(sim808.GPSdata.lat,6);
 
 sim808.latitudeConverToDMS();
 Serial.print("latitude :");
 Serial.print(sim808.latDMS.degrees);
 Serial.print("\^");
 Serial.print(sim808.latDMS.minutes);
 Serial.print("\'");
 Serial.print(sim808.latDMS.seconeds,6);
 Serial.println("\"");
 Serial.print("longitude :");
 Serial.println(sim808.GPSdata.lon,6);
 sim808.LongitudeConverToDMS();
 Serial.print("longitude :");
 Serial.print(sim808.longDMS.degrees);
 Serial.print("\^");
 Serial.print(sim808.longDMS.minutes);
 Serial.print("\'");
 Serial.print(sim808.longDMS.seconeds,6);
 Serial.println("\"");
 
 Serial.print("speed_kph :");
 Serial.println(sim808.GPSdata.speed_kph);
 Serial.print("heading :");
 Serial.println(sim808.GPSdata.heading);
 //************* Turn off the GPS power ************
 sim808.detachGPS();
 }
}

I have mounted the DFRobot shield on a UNO and powered through the barrel connector with a 2_amp 5V stabilised power supply. The DFRobot shield shows a red LED power light and pressing reset flashes the blue LED next to it, but nothing else does anything - the serial monitor just repeats "Sim808 init error". In the video the blue "net" LED flashes even before the SIM card is inserted, but my card does not flash. Do I return the board to Farnell and ask for my money back?

Any help greatly appreciated!

• Majenko: The problem is probably that you are trying to use Serial for both communication with the SIM808 and the PC at the same time. That can't really work.
• Majenko: Do you have a genuine Arduino or a cheap chinese knock-off?
• Bolin: @Majenko: Thanks for help. This is with genuine Arduino Uno from RobotShop not a knock off and the DFRobot shield came from Farnell in a proper labelled box and in antistatic bags for antenna and shield. The code quoted is just one of many I have tried.
• Bolin: Not entirely relevant, but I have just connected up a Chinese generic Sim900 board and it worked 'straight out of the box' using the LastMinuteEngineers' code so I think my DFRobot Sim808 shield is broken/ unserviceable.

Answer 1

The dfrobot board has a weird boot button system that you need to follow to boot up the board. I spent ages attempting to get it to work before I finally achieved anything.

There is a blue led on the board that will flash continuously at different rates if the chip has been correctly powered and is searching for a mobile network.

I noticed that you commented it the while(!sim808.init()) line. This attempts to power the board on automatically, but I do remember something being funny about the implementation.

From doing a while load of research the dfrobot breakout board is not the best hardware implementation of this chip. Actually from memory there aren't any modules I have been able to find which satisfy all my requirements for a project. I'd recommend looking at all the documentation dfrobot provide on their website. Hopefully that should get you working.

Summary: it's an insanely fiddly process to get it working, but the boards are functional