I am making a power failure monitoring system.
I have a 48Vdc as a power source for my arduino uno using a buck converter LM2596HV Step-down Module with input voltage up to 60v and output voltage 3-35v, output current of 2-3A.
I am using a 5v charger as an input. The positive is connected to the interrupt pin and negative to the ground of the arduino.
Using GSM Module I will send notification via SMS.
I would like have it in long run.
Is my setup okay? I have read in electronicshub.org that it is not ideal to use relay in long run because of noise. My question is... what is better to use charger or relay? Do I still need to use optocoupler in charger due to the random rising of voltage (more than 5v)?
I am confident enough that my 48Vdc won't fail to supply the arduino uno. This is my schematic and I hope this will give you info.
I would like to add a resistor across the 5v charger to eliminate the discharge time of the capacitor but I didn't put it in the diagram because you might think it is not necessary.
Is it still necessary to put a cooling fan for the buck converter? I want it for a long run so the heat sink might need help cooling the converter
For just an Arduino I don't expect your converter to get warm at all, but with 48V it's not a good idea to touch it when in use (that's the easiest way to test for heat build up).
Johnny010:
Why have an AC source that firstly drops the voltage to 5V...then shove it through another in-efficient device (buck booster) to 9V...then have it dropped back down to 5V again on the arduino?
The 48Vdc is different from AC source, they are not connected.
If I connect the arduino to the 5V charger then my system will turn off as soon as the power fails.
Since I have an available 48Vdc source that will run with or without the AC power source so I made it like that because it is less complicated.
Are you sure the Uno can power the (unknown) GSM module.
AFAIK most of them draw several amps when active.
The Uno tops at ~200mA on a 9volt supply.
Leo..
Buck converters have a much lower efficiency with a high input voltage and a low output voltage.
At 48volt to 3.3 or 5volt, efficiency might be 70-75%.
The (still unknown) GSM module might need a LiPo battery to deliver those peak transmit currents.
Post a link to the product, not a blurry image.
Leo..
Features:
The GPRS Shield is based on SIM900 module from SIMCOM and compatible with Arduino and its clones. The GPRS Shield provides you a way to communicate using the GSM cell phone network. The shield allows you to achieve SMS, MMS, GPRS and Audio via UART by sending AT commands (GSM 07.07 ,07.05 and SIMCOM enhanced AT Commands). The shield also has the 12 GPIOs, 2 PWMs and an ADC of the SIM900 module(They are all 2V8 logic) present onboard.
Specifications:
With Antenna.
Quad-Band 850 / 900/ 1800 / 1900 MHz - would work on GSM networks in all countries across the world.
GPRS multi-slot class 10/8
GPRS mobile station class B
Compliant to GSM phase 2/2+
Class 4 (2 W @ 850 / 900 MHz)
Class 1 (1 W @ 1800 / 1900MHz)
Control via AT commands - Standard Commands: GSM 07.07 & 07.05 | Enhanced Commands: SIMCOM AT Commands.
Short Message Service - so that you can send small amounts of data over the network (ASCII or raw hexadecimal).
Embedded TCP/UDP stack - allows you to upload data to a web server.
RTC supported.
Selectable serial port.
Speaker and Headphone jacks
Low power consumption - 1.5mA (sleep mode)
Industrial Temperature Range: -40°C to +85 °C
Size: approx. 85 X 57 X 20 mm/3.35 X 2.24 X 0.79 in
Modules like that seem to be powered with an LMZ1200 switching regulator, set to 4.1volt.
Input power comes from the DC socket on the module. 9volt seems ok.
Not sure if that raw voltage is connected to V-in of the Arduino (to power the Arduino).
Could not find a schematic diagram on the page OP linked to, or anywhere else.
Leo..
I assumed that that GSM Module is no different from other GSM Module which can be powered 5-12v that needs at least 1A supply. Because of the efficiency of the buck converter I decided to use 9V. Mounting it in the arduino uno can power the arduino uno as well. (Correct me if I'm wrong)
So my question is... is my set up okay? Or should I modify it?
Hello! I am reviving this thread for a couple of questions.
Instead of using a 5V charger, can I use a relay? Like wiring the AC source to the relay coil, then connect the common contact to ground and normally open contact to the arduino? If it is possible can I use it with this?
It is possible - but you have to find a relay that's designed to be powered by mains AC power instead of the more common 5V DC (or 12V DC for car relays).
I have had tried connecting a 5v charger to the relay coil, then connect the common contact to ground and normally open contact to the arduino and it worked.
Is the relay still necessary? Or can I just directly the positive of the charger to the input pin and negative to the ground like I proposed? I am afraid that I might fry the arduino. Thanks!
