Raspberry Pi Pico with SIM800L module

October 30, 2024, 14:47

dethress

Hey, I'm going to use GSM SIM800L module in my project. I only have 3.3V and 5V power on my breadboard, the problem is that the SIM800L module Power Supply Voltage is between 3.8V and 4.2V. Should I get a step-down DC Converter module to convert from 5V to 4V for the GSM module? Or should I be fine using like a 3x AA battery basket? I'm pretty new to all this so all help is appreciated. Here's the specifications for the SIM800L: > Power Supply Voltage: 3.8V - 4.2V > Recommended Power Supply Voltage: 4V > Current Consumption: > -Sleep mode: < 2.0mA > -Idle mode: < 7.0mA > -GSM communication (average): 350mA > -GSM communication (peak): 2000mA > Module Size: 25 x 23 mm > Communication: UART (max. 2.8V) and AT commands > SIM Card Slot: microSIM (bottom side) > Supported Frequencies: Quad Band (850 / 900 / 1800 / 1900 MHz) > Antenna Connector: IPX > Status Indicator: LED > Operating Temperature: -40 to +85°C And here's the specifications for a step-down DC converter I found (Step-Down DC Converter Module LM2596S 1.5-35V 3A): > Input Voltage (DC): 3.2V-35V > Output Voltage (DC): 1.5V-35V > Adjustment: Potentiometer control > Output Current: 2A, maximum 3A with a heatsink > Efficiency: 92% > Operating Frequency: 150kHz > Operating Temperature: -40°C to 85°C > Dimensions: 43mm x 20mm x 14mm (LWH)

oops.se

Please post link to SIM module as many of them has voltage regulator

oops.se

I would use a voltage regulator, but be careful the SIM uses a lot of current when transmitting on full power so take that into your considerations when designing.

dethress

I've already bought the step-down DC converter, I'm just wondering how to properly connect it to the module and power supply now. I only have male-male jumper cables, should I solder them into the converter's board?

blackmage6618

Yes or buy additional female-jumper adapter

dethress

I just bought jumper cables with peak current 2A. Do you perhaps know if I have to set up the 4V on out with 2A current? Or just set it up for 4V on out regardless and it'll run? Also, the power voltage shouldn't play a role in communication voltage right? According to specification, SIM800L communication voltage peaks at 2.8V and to my knowledge Pi Pico works with modules up to 3.3V

oops.se

Actually the voltage for the data communication is 2,8 volt +/- 0,1 volt according to the datasheet https://nettigo.pl/attachments/385 You can either use a voltage converter (IC or transistor circuit) or a voltage divider (two resistors) to convert Raspberry Pi Pico 3,3 volt to 2,7 - 2,9 volt.

oops.se

The 2A is probably a value classed as "Worst Case" like max radio transmitter output while registering to a cell tower with bad radio signal condition.

oops.se

An advice, read the datasheet from the manufacturer rather than a web page.