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If you will compare this to smartphones, marginal is one bar, OK is two bars, good is three bars and excellent is four bars.

Here is a handy list of dBm levels and what they mean:

I was able to connect to a network at -70 dBm. 111 dBm is also a bad number for signal reception. 115 dbm is the lowest signal strength value and would typically mean that the SIM800L is on a network blind spot. For this project, I utilized these two:īoth returns integers indicating the received signal strength indication (RSSI) and network status.įor getRSSI(), these are the possible return numbers:ĭBm is short for decibel per milliwatt and is a common unit for signal strength. I have created some Arduino sketches for SMS and calls by using the functions in this library. The FONA library from Adafruit contains a lot of functions that simplifies interfacing with the SIM800L. The TP4056 is completely optional for this project, but it is very useful in charging up the LiPo battery. The Arduino Nano is powered by the 3.7 V battery connected to the 5 V pin. Of course, you need to initialize the serial port first. Just replace display.print() on the sketch below with Serial.print(). If you don't own a Nokia 3310 LCD and is not planning to buy one, you can use the serial port instead. The Nokia 3310 LCD breakout board runs on 3.3 V and not on 3.7 V! My solution is to connect its VCC pin to the 3.3 V of the Arduino Nano and it works. If the LED blinks very fast, this means it's connected through GPRS. You will know if it's connected to the network when it blinks every three seconds. If it is blinking every second, this means it is searching for a network. If the power to the SIM800L is enough, the on-board LED starts blinking.

I decided to buy a battery online and it works wonderfully. This is after a lot of tests, including using regulators, variable power supplies, etc. The breakout board absorbs 2 A at peak but I found out that a 1000 mAh battery works. The best power source is a 3.7 V LiPo battery with at least 1000 mAh rating. It goes without saying that the SIM800L breakout board is very particular to the power applied to it. Arduino Nano and SIM800L Connection: SIM800LĪrduino Nano and Nokia 3310 LCD Connection: Nokia 3310 LCD