This is my first time building and programming. I need help please! I have the DHT11 Digital humidity temperature sensor and the sainsmart MQ131 I found a wire diagram online im not sure if it will work?
And I need the sketch can someone help me please?
for the DHT11 you could use the library described here - Arduino Playground - DHT11Lib -
That should get you started.
The wiring diagram you have shown is laugable. Not only are the sensors configured totally differently to the ones you have chosen but the battery circuit is absolutely NUTS.
The UNO has it's own 5v power regulator built in. You just have to connect that 9v battery to the barrel connector.
this is how the dht11 connects to the UNO
The sainsmart detector is another story. I've found a datasheet for the sensor on the board HERE. (MQ131)
But looking at the board (As shown here) It's apparently got some other chip on board. So attempting to figure out how that works will take a bit of investigation. It looks like the info on Sainsmarts page just shows the data for the sensor. (not thier board WITH the sensor)
I'll keep looking
Thats what I was wondering why they had the 9v wtht the regulator. Then having a second power for the board. These are the 2 sensor I bought they should be here tomorrow. Thank you for everyones help!!! I love electronics but am trying to learn the andrino
Oh one more question do I have to use a 9v battery cause I have a 9v 200ma power supply? That has a perfect plug for the arduino plug. Is that enough ma If not I have boxes of power supplies.
Woul it be easier to return the MQ131 and get the right sensor? Does the lcd display wire the same way as shown in this diagram?
Actually i may have dismissed that fritzing thing too soon. Having read up a bit more on the issue, The MQ131 has a heater circuit that is very critical about it's supply voltage. Drawing that from the 5v of the UNO may not be the best option. The raw sensor itself actually requires 6v. But since the board you have purchased is not just a raw sensor, it will doubtless use it's own methods to provide the stable supply to the sensor.
Hopefully the documentation that comes with the board will make things clearer.
I was reading this about the heater on some sensors. Could this be why they used a different power supply and regulator for the sensors?
The heater
The voltage for the internal heater is very important.
Some sensors use 5V for the heater, others need 2V. The 2V can be created with a PWM signal, using analogWrite() and a transistor or logic-level mosfet.
The heater may not be connected directly to an output-pin of the Arduino, since it uses too much current for that.
Some sensors need a few steps for the heater. This can be programmed with an analogWrite() function and delays. A transistor or logic-level mosfet should also in this situation be used for the heater.
If it is used in a battery operated device, a transistor or logic-level mosfet could also be used to switch the heater on and off.
The sensors that use 5V or 6V for the internal heater do get warm. They can easily get 50 or 60 degrees Celcius.
After the "burn-in time", the heater needs to be on for about 3 minutes (tested with MQ-2) before the readings become stable
KenF:
Actually i may have dismissed that fritzing thing too soon. Having read up a bit more on the issue, The MQ131 has a heater circuit that is very critical about it's supply voltage. Drawing that from the 5v of the UNO may not be the best option. The raw sensor itself actually requires 6v. But since the board you have purchased is not just a raw sensor, it will doubtless use it's own methods to provide the stable supply to the sensor.Hopefully the documentation that comes with the board will make things clearer.
lol I was just reading the same thing