I talked to the GPRSbee designers at SODAQ, and they should have more of the modules in stock next week. You’ll have to order directly from SODAQ’s website, they aren’t available anywhere else. The GPRSbee comes with an antenna, you don’t need to buy anything else to make it work as a signal-strength tester. If you want to use a module for actually sending data, you will need a SIM card for a carrier that has 2G service, and the best option for that is http://hologram.io
But you don’t need a SIM card if you’re just making a signal tester.
As for the solar panel, the 0.5w panel from Seeedstudio fits inside the clear-lid enclosures I usually use for the Mayfly, but you have to modify the panel to get it to fit since it’s about 4mm too long. I use a special “nibbler” tool to do that, because if you don’t do it carefully it will damage the panel. You don’t actually have to use the solar panel if you’re building a signal tester. I just do it so that the battery can be recharged easier since we loan those kits to people who don’t have battery chargers.
Probably the easiest thing to buy for building all of this would be to use our Mayfly Starter kit: https://www.amazon.com/dp/B01FCVALDW
It’s currently out of stock, but we’ll hopefully have more online in a few weeks. It come with the clear-lid case, has the solar panel, and the Grove cable you’ll need to connect to the display.
The display I like to use with the Mayfly is this one: https://www.amazon.com/Grove-128×64-Board-Arduino-Raspberry/dp/B01D5GLDJ2
It has a Grove port on it so you can simply connect it to the Grove I2C port on the Mayfly. There are other similar displays that will work, but none that are as easy to connect since I only know of this one display with a Grove port.
If you wanted to add a GPS module, you’d need a way to connect it to the Mayfly. There are a couple different ways to do it, but it depends on which GPS module you want to use. I could suggest a few ways if you really want to do it.
As for the code, I can also provide that. If you’re using the SwitchDoc OLED display I mentioned above, you’ll need the drivers from here: https://github.com/switchdoclabs/SDL_Arduino_SSD1306
The code:
#include <SDL_Arduino_SSD1306.h> // Modification of Adafruit_SSD1306 for ESP8266 compatibility
#include <AMAdafruit_GFX.h> // Needs a little change in original Adafruit library (See README.txt file)
#include <SPI.h> // For SPI comm (needed for not getting compile error)
#include <Wire.h> // For I2C comm, but needed for not getting compile error
SDL_Arduino_SSD1306 display(4); // FOR I2C
long previousMillis = 0; // will store last time display was updated
// Comment out one of the 2 lines below, depending on your Mayfly version
// float batt_ratio = 1.47; // Use this line for Mayfly v0.3 and v0.4
float batt_ratio = 4.7; // Use this line for Mayfly v0.5 and newer
int batteryPin = A6; // select the input pin for the potentiometer
int batterysenseValue = 0; // variable to store the value coming from the sensor
float batteryvoltage;
// the follow variables is a long because the time, measured in miliseconds,
// will quickly become a bigger number than can be stored in an int.
long interval = 5000;
int index = 1;
void setup()
{
Serial.begin(57600); //Start the serial connection with the computer
Serial1.begin(9600); //UART to the Bee module
pinMode(23, OUTPUT); // Bee socket DTR pin
digitalWrite(23, HIGH); // on GPRSbee v6, setting this high turns on the GPRSbee. leave it high to keep GPRSbee on.
pinMode(8, OUTPUT); // Mayfly Green LED
digitalWrite(8, HIGH); //turn on the Green LED
display.begin(SSD1306_SWITCHCAPVCC, 0x3C, false); // initialize with the I2C addr 0x3C (for the 128x64)
display.clearDisplay();
display.setRotation(2);
display.setTextSize(2);
display.setTextColor(WHITE);
display.setCursor(0,0);
display.println("Mayfly");
display.println("GPRS 2G");
display.println("Signal");
display.println("Tester");
display.display();
Serial.println("Mayfly GPRS 2G RANGE TESTER"); //prints to the computer serial
delay(100);
}
void loop()
{
unsigned long currentMillis = millis();
if(currentMillis - previousMillis > interval) {
previousMillis = currentMillis;
Serial1.print("AT+CSQ\r"); // query the Bee module for signal strength report
delay(2000);
int s = Serial1.parseInt();
int junk = Serial1.parseInt();
batterysenseValue = analogRead(batteryPin);
batteryvoltage = (3.3/1023.) * batt_ratio * batterysenseValue;
Serial.print("s= ");
Serial.println(s);
if (s == 0)
{
Serial.print(" None");
}
else if (s > 1 && s <= 9)
{
Serial.print(" Bad");
}
else if (s >= 10 && s <= 14)
{
Serial.print(" Ok");
}
else if (s >= 15 && s <= 19)
{
Serial.print(" Good");
}
else if (s >= 20 && s < 31)
{
Serial.print(" Great!");
}
float percent = map(s, 0, 30, 0, 100); // redefines the 0-30 levels to a 0-100% range
display.clearDisplay();
display.setTextSize(2);
display.setTextColor(WHITE);
display.setCursor(1,0);
display.print("Sample:");
display.println(index);
display.print("Signal:");
display.print(percent,0);
display.println("%");
display.print("Qual:");
if (s == 0)
{
display.print("None");
}
else if (s > 1 && s <= 9)
{
display.print("Bad");
}
else if (s >= 10 && s <= 14)
{
display.print("okay");
}
else if (s >= 15 && s <= 19)
{
display.print("Good");
}
else if (s >= 20 && s < 31)
{
display.print("Great");
}
display.println();
display.setTextSize(1);
display.print("1-30: ");
display.println(s);
display.print("Battery: ");
display.print(batteryvoltage);
if (batteryvoltage > 3.75)
{
display.print(" ok");
}
else if (batteryvoltage < 3.75)
{
display.print(" LOW!");
}
display.display();
index++;
}
}
David Bressler
Matt Barney
Shannon Hicks
Paul Wilson
Carol Armstrong
Matt Barney
Shannon Hicks
Paul Wilson
Carol Armstrong
