user59398: I've read post that it's possible to connect multiple Ultra-Sonic Sensors to one Arduino.
But I have a few questions:

If I use Arduino Uno, what is the maximum number of Ultra Sonic Sensors that I can connect one Arduino UNO?

Is there any option to power Arduino UNO in some kind of low-power mode so I can achieve power autonomy for at least 90 days.(I'm referring to battey life, or solar powered solutions)

Can Arduino UNO work on the low/high temperatures (e.g. -20 / +50 Celsius degrees), and what is the known work temperature range?

How to secure jumpers/cables to work on extreme temperatures (e.g. -20 / +50 Celsius degrees)
Thanks in advance :D



user58962: 
You did not specified, what kind of ultrasonic sensor you want to use so I assume use of "standard" ultrasonic Arduino modules (like hc-sr04), which need 4 pin (VCC, GND, TRIGGER and ECHO). Since Arduino Uno has got 20 IO pins (6 analog and 14 digital), you can use 10 pins as outputs for TRIG signals and 10 as inputs for ECHO signals and thus connect up to 10 ultrasonic modules to one Arduino Uno.  
In general, Arduino Uno is not designed for low-power applications. If you want more specific answer, you should ask more specific question...
Working temperature of Arduino Uno is -40 to 85 °C.
One of the options is using a terminal shield with screw terminals, e.g something like this.


59398: <p>I've read post that it's possible to connect multiple Ultra-Sonic Sensors to one Arduino.
But I have a few questions:</p>
<ol>
<li><p>If I use Arduino Uno, what is the maximum number of Ultra Sonic Sensors that I can connect one Arduino UNO?</p>
</li>
<li><p>Is there any option to power Arduino UNO in some kind of low-power mode so I can achieve power autonomy for at least 90 days.(I'm referring to battey life, or solar powered solutions)</p>
</li>
<li><p>Can Arduino UNO work on the low/high temperatures (e.g. -20 / +50 Celsius degrees), and what is the known work temperature range?</p>
</li>
<li><p>How to secure jumpers/cables to work on extreme temperatures (e.g. -20 / +50 Celsius degrees)</p>
<p>Thanks in advance :D</p>
</li>
</ol>
 58962: <ol>
<li>You did not specified, what kind of ultrasonic sensor you want to use so I assume use of "standard" ultrasonic Arduino modules (like hc-sr04), which need 4 pin (VCC, GND, TRIGGER and ECHO). Since Arduino Uno has got 20 IO pins (6 analog and 14 digital), you can use 10 pins as outputs for TRIG signals and 10 as inputs for ECHO signals and thus connect up to 10 ultrasonic modules to one Arduino Uno.  </li>
<li>In general, Arduino Uno is not designed for low-power applications. If you want more specific answer, you should ask more specific question...</li>
<li>Working temperature of Arduino Uno is -40 to 85 °C.</li>
<li>One of the options is using a terminal shield with screw terminals, e.g something like <a href="https://arduino-shop.eu/arduino-platform/1200-arduino-uno-terminal-shield.html" rel="nofollow noreferrer">this</a>.</li>
</ol>
