People usually still have water flowing during a commercial power failure. So, you will loose all stored readings and take no new readings. Why bother if this happens frequently?
The circuit appears to connect a 5V sensor output with a 3.3V input. A logic level shifter is required. A 1K;2K resistor divider will work. Perhaps the flow sensor will work on 3.3V, in which case drop the boost converter.
Yes, that 5V boost converter will not be as efficient as you are hoping, I suspect. Your schematic labels it as 13uA quiescent current, but I imagine that is when it is disabled and not producing 5V output. The quiescent current when it is producing 5V will be nearer 100x as much, I suspect. I hope I am wrong about this, so please post a link to its specs, because if it is as efficient as you hope, I want some of those too!
It mentions that working voltage for it is 5V~15V (DC). So keep this boost converter?
Yes, 13uA is when it’s not supplying 5V, but in my case the device most of the time is idle, so I believe this boost converter is acceptable? I am not sure actually how often the device will be used in regards to the power usage and the choice whether to use boost converter, buck, LDO, whatever. What would you do here to be safer for unknown usage patterns of device? Keep this converter or use a different component?
I don't get how your circuit is supposed to work. Can't water start flowing at any time? If so, won't your sensor completely miss that if it is not powered with 5V full time?
The sensor may work at 3.3V, regardless. At 5V, you still have the problem of level conversion. so save yourself trouble by buying a flow switch that IS specified to work at 3.3V. Some flow sensors have a reed switch that will work at any voltage.
If you don't know what capacitors do, then it is way too early to be "designing" circuits.
Sorry about that, it should’ve went straight to 3V3 pin right? Keeping C3 connected to the GND.
I don’t understand how “it is not powered with 5V full time” here? What I meant before is that there will not be no constant flow of water, let’s say at max 1-2 hours of constant flow water a day. But now as I see, there is nothing I can do that sensor must be powered all the time at 5V to detect flow, right? It won’t survive on several batteries for long.
From what perspective this way is better? I thought pro mini + lora would be better in terms of power consumption.
if you can find a module with Microcontroller + LoRa that meets your requirements it saves interconnecting modules reducing the possibility of poor connections and intermittent problems
for example, currently looking at using a Heltec wifi-lora-32-v3 module (as a daughter board on a custom PCB) plus solar panel on a water monitoring project
found this program which uses a Pro Mini 3.3V + RFM95W to transmits text using arduino-LoRa library
// Pro Mini RFM95 sender
// NOTE: RFM95 requires external 3.3V supply
// Pro Mini 3.3V output insufficent for transmitter OK for receiver
// Tools>Board select Pro Mini 5V or 3.3V
// Pro_Mini connections
// Pro_Mini SCK pin GPIO13 to RFM95_pin SCK
// Pro_Mini MISO pin GPIO12 to RFM95_pin MISO
// Pro_Mini MOSI pin GPIO11 to RFM95_pin MOSI (alternate connection)
// Pro_Mini SS pin GPIO 10 to RFM95 SS
// Pro_Mini pin GPIO4 to RFM95 Reset
// Pro_Mini pin GPIO2 to RFM95 DIO0
// Pro_Mini pin GPIO6 to RFM95 DIO1 (required for LoRaWAN)
#include <SPI.h>
#include <LoRa.h>
int counter = 0;
void setup() {
Serial.begin(57600);
while (!Serial);
Serial.println("\n\nPro Mini RFM95 LoRa Sender");
//void setPins(int ss = LORA_DEFAULT_SS_PIN, int reset = LORA_DEFAULT_RESET_PIN, int dio0 = LORA_DEFAULT_DIO0_PIN);
//LoRa.setPins(8,4,7); // for Lora 32u4
//LoRa.setPins(10,9,2); // for UNO LoRa shield
LoRa.setPins(10,4,2); // for Pro Mini
if (!LoRa.begin(866E6)) {
Serial.println("Starting LoRa failed!");
while (1);
}
}
void loop() {
Serial.print("Sending packet: ");
Serial.println(counter);
// send packet
LoRa.beginPacket();
LoRa.print("hello ");
LoRa.print(counter);
LoRa.endPacket();
counter++;
delay(5000);
}
LoRa Receiver
Received packet 'hello 0' with RSSI -50
Received packet 'hello 1' with RSSI -50
Received packet 'hello 2' with RSSI -53
Received packet 'hello 3' with RSSI -53
Received packet 'hello 4' with RSSI -53
Received packet 'hello 5' with RSSI -53
Received packet 'hello 6' with RSSI -53
Received packet 'hello 7' with RSSI -53
Received packet 'hello 8' with RSSI -50
