user13576: I would like to place analog sensor in a place, that is impractical to reach with a wire. But it looks like an overkill to use a separate small Arduino board to read and transmit sensor signal to main Arduino board at a close range (~1 m). 
Is there a cheap practical way to setup such sensor signal broadcast over RF without using Arduino board? Something that could work for considerable duration with a small tablet like battery?

user10794: You don't have to use a $30 Arduino. You can make a "breadboard" one for a few dollars, like this:

$5 for the chip and a couple of dollars for a couple of capacitors and resistors.

Add to that a NRF24L01 transceiver like this:

Available from eBay for around $1 each. You need two, as you need to transmit from one and receive from another.
So the whole thing could be done for under $10.


Something that could work for considerable duration with a small tablet like battery?

See Power saving techniques for microprocessors

user4143: I would recommend investigating the ESP8266 modules.  Many people use them as a WiFi interface to an Arduino, but they are also capable of being used completely standalone.
You can pick up a cheap module and program it using a readily available USB to TTL UART adapter using the ESP8266 plugin to the Aduino IDE.
https://github.com/esp8266/Arduino
It's like having an Arduino and a WiFi interface all embedded in one chip, and the modules are tiny too - perfect for embedding in a project.
There are many different modules available, some with more pins than others for IO.  The best one is the NodeMCU since it has the programming interface built in (go for version 1.0 not version 0.9 since it has better IO options), but the higher end ESP8266 modules on carrier boards (ESP-12, etc) are as good, if a little harder to work with.

13576: <p>I would like to place analog sensor in a place, that is impractical to reach with a wire. But it looks like an overkill to use a separate small Arduino board to read and transmit sensor signal to main Arduino board at a close range (~1 m). </p>

<p>Is there a cheap practical way to setup such sensor signal broadcast over RF without using Arduino board? Something that could work for considerable duration with a small tablet like battery?</p>
 10794: <p>You don't have to use a $30 Arduino. You can make a "breadboard" one for a few dollars, like this:</p>

<p><a href="https://i.stack.imgur.com/jBTgZ.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jBTgZ.jpg" alt="Breadboard Arduino"></a></p>

<p>$5 for the chip and a couple of dollars for a couple of capacitors and resistors.</p>

<hr>

<p>Add to that a NRF24L01 transceiver like this:</p>

<p><a href="https://i.stack.imgur.com/WDHUg.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WDHUg.jpg" alt="NRF24L01"></a></p>

<p>Available from eBay for around $1 each. You need two, as you need to transmit from one and receive from another.</p>

<p>So the whole thing could be done for under $10.</p>

<hr>

<blockquote>
  <p>Something that could work for considerable duration with a small tablet like battery?</p>
</blockquote>

<p>See <a href="http://www.gammon.com.au/power" rel="nofollow noreferrer">Power saving techniques for microprocessors</a></p>
 4143: <p>I would recommend investigating the ESP8266 modules.  Many people use them as a WiFi interface to an Arduino, but they are also capable of being used completely standalone.</p>

<p>You can pick up a cheap module and program it using a readily available USB to TTL UART adapter using the ESP8266 plugin to the Aduino IDE.</p>

<p><a href="https://github.com/esp8266/Arduino" rel="nofollow">https://github.com/esp8266/Arduino</a></p>

<p>It's like having an Arduino and a WiFi interface all embedded in one chip, and the modules are tiny too - perfect for embedding in a project.</p>

<p>There are many different modules available, some with more pins than others for IO.  The best one is the NodeMCU since it has the programming interface built in (go for version 1.0 not version 0.9 since it has better IO options), but the higher end ESP8266 modules on carrier boards (ESP-12, etc) are as good, if a little harder to work with.</p>
