Need assistance to select components


I'm new to Arduino and I want to find the components for a device that I want to build.
This is the list:

  • main board
  • temperature sensor
  • humidity sensor
  • light sensor
  • altitude?
  • accellerometer
  • pressure sensor
  • air quality sensor?
  • bluetooth connection
  • microphone
  • earbuds

The list of interactions which I plan to have:

  • pass sensor data to a mobile device via bluetooth. Requirements: the device shouldn't have to upload data to server to be converted. Interval of data transmission should be 5 seconds.
  • bluetooth connection should serve as a bridge between the microphone/earbuds and the mobile device.

Other notes:
This is a personal project, so the budget isn't big.
If there are devices can do that already, I'm opened to know them.
Also, if is anyone who can assemble such device, I'm opened to pay for the work.

Thanks in advance

If you are new to electronics and programming, start with an Arduino Uno and a temperature sensor, like the LM35. Here is a tutorial : Overview | TMP36 Temperature Sensor | Adafruit Learning System

If you know some electronics and programming already, get a bluetooth module. Adafruit has a lot good modules. This the newest one : Adafruit Bluefruit LE Micro - Bluetooth Low Energy + ATmega32u4 : ID 2661 : $26.95 : Adafruit Industries, Unique & fun DIY electronics and kits
You can add more sensors to it, and see how far you get.

The microphone and earbuds part might not be possible. I don't know what you want to do with that.
Cheap air quality sensor do work well (MQ-2 and MQ-135 are less than 2 dollars on Ebay), but they require a lot current because they have a heater inside. The more sophisticated an air sensor gets, the more (a lot more) it costs.

Temperature : DS18B20 (you need the OneWire library).
Humidity : Good and accurate humidity sensors are rare. The DHT22 is often used, but it can be totally inaccurate. The Honeywell HIH-6xxx series is good or find a good one at
Altitude : With a baromic pressure sensor. BMP180 or BMP280 or BME280.
Accelerometer : What do you want to do with it ? There are many good ones, cheap and expensive.
Pressure sensor : This is the same as the altitude sensor.

Make sure to learn each piece of the project separately in its own small Arduino program. Only start to join them together after you can make all the parts work separately.

And it will be much easier to get advice here with small programs.

You may find some useful stuff in planning and implementing a program


Thanks to both of you.

I've identified 2 sensors to start with:
Altitude + pressure: BMP180
Humidity: HIH 4030

Once I have success with these, I plan to try the BLE from adafruit recommended by Peter.

I was wondering if there are smaller boards than Arduino Uno, of course compatible with the sensors mentioned.

I'm pretty new to electronics (although I'm not a stranger). What tools I would need?

For programming, I'm not afraid to learn any new language, but I found this popular framework, which makes me feel in my habitat:


I was wondering if there are smaller boards than Arduino Uno, of course compatible with the sensors mentioned.

Yes. Have a look at the products page. However I suggest that you use an Uno for learning and prototyping as almost all add-ons and software works with it.

You can also build a breadboard Atmega 328 easily on a piece of veroboard.


I suggest to step out of your habitat :grin:
Arduino uses the GCC compiler, which is normal "c" and "c++" language.
Every library uses that, so you have to get to know that anyway.

When you use the johnny-five framework, you have to learn both the johnny-five and the Arduino "c" and "c++" usage.

Is that Adafruit Bleutooth LE Micro a board which includes the bluetooth module? (

Yes, the metal box is the bluetooth part, the black chip is the Arduino Leonardo compatible part.

Actually, the requirements are more close to a wearable.
I found Flora: Overview | Getting Started with FLORA | Adafruit Learning System

Is it possible to install the sensors mentioned on it?
Altitude + pressure: BMP180
Humidity: HIH 4030

Does this Flora requires a sensor shield?

I'm so brand new to both electronics and Arduino, so I'll have to apologize for my mumbling.

The Flora is a Arduino 3.3V board (the microcontroller runs at 3.3V)
The BMP180 is for 3.3V.
The HIH-4030 requires 5V, you need another humidity sensor.

If you use the BME280 instead the BMP180, you have humidity. And the BME280 runs at 3.3V.

If you are brand new to electronics, buy an Arduino Uno and a few sensors, and try them. You have to start somewhere, and it is probably not possible to finish your final project without a few tests and trial and errors.

For myself, I need to try a number of things to get some feeling with my project, before making final decisions.
At this moment I have a plant that is going droop, because my exponential calculation for my home made soil moisture sensor is not perfect :o When I started the project, I didn’t even know if my moisture sensor would work at all. The “sensor” is only two strips of Copper-Nickel tape :wink:

Btw, does the humidity sensor works if is covered, or has to be in direct contact with the air?

And one more question, how do I build a case for the device?

The humidity needs (some) contact with the surrounding air. Some holes in a case should be enough.

You can buy cases from very cheap to very expensive.
Very cheap is an old black plastic VHS tape box.
I have a few cases, but when I start a new project I never have the right case.

What issues I could encounter as novice in electronics, in the first project?

In programming, I just erase the code and start again. In electronics is possible to destroy the components?

Java is not my main skill, but yet last year I learned Android+Java from the first project and managed to make a pretty complex application. Of course it was hard.

I'm thinking to do the same: buy the board I want to use in the final product and add sensors/features as soon as one is successfully added.

Basically, I want:

  • adafruit Flora
  • BME 280

Once these are working fine, I add Flora BLE and go further with coding part.

I'm only concerned about the electronics. Which is more difficult for people, electronics or coding part?

Which is more difficult for people, electronics or coding part?

Depends on whether one is a hardware engineer, software engineer, some combination of experience, etc.
Being a hardware design engineer, I find the electronics part easier. Altho there is plenty of coding I've done so many parts of that are not that difficult either.

Ok, I'm at the checkout point finally:

My questions now:

  • are those items compatible?
  • is the LiIon battery charging if I connect the board via micro B port?
  • what other tools and materials I need to put everything together, considering that I don't have anything?


The BME280 is also compatible with the Flora (both are 3.3V).

The battery is not charged when the Flora is connected to the usb bus. You need a seperate charger. Adafruit has them as well, for example this one is linked from the Flora page :

Are the alligator clips the only way to connect everything? At Adafruit they often use conductive thread :

I was thinking to use the aligator clips to test the connections, but I think that you are right with the conductive thread.

Regarding the charger, I was hoping to have the same method as in the case of mobile phones. Plug the wire in the device for reading data and during this time it can charge.

In this case, if the battery will be charged with a separate charger and the data will be transferred via bluetooth, the usb port will not be useful I guess (besides uploading the code to it).