No, I need measure the value too.
Yes⌠I was referring only to the Arduino⌠and yes that means you can use both, one to connect to the Blynk server (via the USB-link script) and the other to see what is happening on a separate serial monitor (like termite, since you will not be able to use the IDE monitor).
You donât need such a thing on a Wemos as it communicates to the server via WiFi and leaves the programming port clear for use on the IDE serial Monitor.
Then if the sensor can run on 3.3v you should be able to connect directly to A0 as is (the whole 3.2v or 3.3v issue is not as critical as it sounds)
Can the flame sensor powered with only 3.3V? Cause, as far as I know, the flame sensor need 5V.
Am I wrong?
The DX listing for your sensor states:
Other Voltage: DC 3~5.5V
That is why I asked you to try 3.3V and if it doesnât work try 5V, but with all the other wires disconnected.
You need to do the trim pot stuff before connecting up the data wires and running the sketch.
1 Like
I donât know⌠never had one to play around with. If running on 5v, then use a 180K resistor to be safe⌠that will drop the incoming MAX to 3.3v and the code will properly read the value.
If you have a multimeter and a few resistors (EDIT or yes a trim pot as @costas suggested⌠I missed that part) , then always best to manually check them and use the one with the closest value to your needs BEFORE applying the power.
Trim pot is on the sensor board and used to calibrate it, It is nothing to do with the voltage divider circuit.
Ok, Iâll try it first.
Ha⌠got ya 
Although where I was going was that one could use a 200+K trimpot and adjust it down to 180K if no other suitable resistor was available.
See up to and including Step 2 regarding the initial flame sensor test at http://www.instructables.com/id/Arduino-Modules-Flame-Sensor/
Might be slightly different for your sensor but I am guessing they are all pretty much the same.
Trim pots normally on PCBâs come preset to the required value but if the LEDâs are on without a flame it suggests they are not set correctly. There is a slight chance that your LEDâs are always on but I suspect they are to confirm the presence of a flame as per the Instructable.
I know what you were referring to but maybe @Maria didnât. We are awaiting a delivery of PCB trim pots for one of our projects.
1 Like
Apparently, the sensor have 2 LEDs. One LED always on though the fire is off, and the other LED only on when the fire is on too. It can work on 3.3V and 5V. Then, what else?
Good so you are making progress. Does 3.3V and GND (without all the other connections) work OK as far as the LEDâs are concerned? Or do you need 5V and GND (nothing else connected)?
You might already know what @Gunner and I were discussing but I donât want you to destroy the WeMos so donât connect up the other wires unless you are 100% sure you know what you are doing.
1 Like
Yes, both 3.3V and 5V with GND can work well with nothing else connected. The LED just light up when the fire is on.
1 Like
Good so letâs forget all about 5V and just make the connections with 3.3V.
Did you need to adjust the trim pot on the sensor or were the LEDâs fine âfrom the factoryâ?
Let us know what you get on Serial Monitor with 3.3V used.
Without upload any sketch?
If yes, then the serial monitor like this:
As long as you have disconnected all the 5V stuff then itâs OK to upload the sketch.
Bit worried that your last upload gave an invalid token error. Maybe you deleted a project?
Is deleted project means close latest program? My latest program indeed have been closed, is it mean the program deleted?
I tried to upload blink sketch, but nothing appear in serial monitor. Beside, I donât know how much the baud rate, in that sketch nothing baud rate mentioned. I also set the baud rate in serial monitor 115200 and nothing happened in serial monitor.
When the fire is on, nothing happened too in serial monitor.
Paste Serial Monitor details even with no sensor readings. You donât have to do screenshots, paste all the text but remove your token details etc.
Nothing text appear,the serial monitor just empty. Should I change the baud rate again?