Simply Automationized: October 2015

Since there are many uses for ultrasonic sensors (Robots, Liquid Level Sensor, Motion Sensor, Vehicle Parking/Backup, on and on....) I compiled a list of 20+ sensors with their min/max ranges along with precision and how it interfaces with your RPi or Arduino. Prices Ranging from ~$2 usd to nearly $175+ usd. You can connect several to your project with all of these sensors.

Sensor	Min Range	Max Range	Freq.	Precision	Interface	Price (usd)
SRF08	3cm	6m	?	3-4cm	I2c	$50
SRF10	6cm	6m	40 KHz	?	I2c	$33
SRF02	15cm	6m	40 KHz	?	I2c/UART	$14
SRF04	3cm	3m	40 KHz	?	Pulse	$22
SRF05	1cm	4m	40 KHz	?	Pulse	$22
MaxSonar-EZ Series	15cm	6.45m	42 KHz	2.54cm	PWM / Serial / Analog / I2c	$25-$40
ProxSonar-EZ Series	3cm	3m	42 KHz	2.54cm	USB / Serial / Digital Logic	$50
SRF01	0cm	6m	40 KHz	3-4cm	UART	$28
SRF235	10cm	1.2m	235 KHz	3-4cm	I2c	$109
URM04	4cm	5m	40 KHz	1cm	RS485	$26
URM06	20cm	10m	49.5 KHz	1cm	Analog	$59
MaxSonar-WR Series	30cm	10m	42 KHz	.1cm (1mm)	PWM / Serial / Analog / I2c	$99-$175
ParkSonar-EZ Series	15cm	1.84m - 3.66m	42 KHz	2.54cm	PWM / Serial / Analog / I2c	$30
MaxSonar-AE Series	1mm	7m	42 KHz	1cm	Serial / Analog / I2c	$40-$55
US-100	2cm	4.5m	40 KHz	0.3cm	Pulse / UART	$4
US-020	2cm	7m	40 KHz	0.3cm	Pulse	$5
US-015	2cm	4m	40 KHz	3cm	Pulse	$4
HC-SR04	2cm	4m	40 KHz	3cm	Pulse	$3
HY-SRF05 / HC-SR05	2cm	4.5m	40 KHz	0.2cm	Pulse	$2
DYP-ME007Y	30cm	3m	40 KHz	1cm	Pulse	$13
Parallax PING)))	2cm	3m	40 Khz	?	Pulse	$30
URM37	2cm	5m	?	1cm	PWM / UART	$14

Before we start lets first name off the different ways to interface things to your raspberry pi. I2c, SPI, UART, digital pins, usb (which will be one of the previous serial protocols just converted to USB), and ethernet (same as usb serial with some MCU with an ethernet interface). If the raspberry pi had an ADC I would've included some of them. If you want to use an analog sensor you'd need to find an ADC --> I2c/SPI board/module.

This list I will update as I find more:

Sensor	Temperature Low	Temperature High	Precision	Interface	Price (usd)
DS18B20	-55°C (-67°F)	125°C (257°F)	0.0625°C (0.11°F)	Dallas 1-Wire	$2
DHT11	0°C (32°F)	50°C (122°F)	1°C (3.3°F)	1-wire	$5
DHT22/AM2302	-40°C (-40°F)	80°C (176°F)	0.1°F (0.18°F)	1-wire	$5
AM2312	-40°C (-40°F)	80°C (176°F)	0.1°C (0.18°F)	I2c	$15
MCP9808	-40°C (-40°F)	125°C (257°F)	0.0625°C (0.11°F)	I2c	$5

DS18B20

East of Setup: Medium

Temperature Range: -55°C to +125°C (-67°F to +257°F)

Interface: Digital 1-Wire

Benefits: Can daisy chain many of them along the same serial bus.

Limitation: Requires a 4.7k resistor. The communication is slow (about 1 second per sensor) which can slow down how often you're getting updates if you have 10+ on the bus. For I2c/UART (need interface board for I2c/UART)

Price: $2

Links For Setup: Adafruit Tutorial, ModMiPi Tutorial,
Some Python Libraries: Github

DHT11 / DHT22 / AM2302

I put these three together because of their similarities. The AM2302 / DHT 22 have a higher and lower temperature range. Each type requires a 10k resistor per sensor.

Temperature Range: AM2302/DHT22 -40°C to +80°C (-40°F to +176°F)

Temperature Range: DHT11 0°C to +50°C (32°F to +122°F)

Interface: Digital 1-wire (not same as Dallas 1-Wire protocol)

Benefits: Senses humidity. DHT11 isn't too expensive

Limitations: DHT11 has a limited temperature range. Not waterproof unless you buy an encapsulated version, which will not sense humidity as well.

Price: DHT11 ~$5, AM2302 / DHT22 ~$6-$20

Links For Setup: Adafruit

Some Python Libraries: Github Adafruit

AM2321

Since this sensor uses I2c I separated it from the above AM2302/DHT22. Requires pull-up resistor 3l-10k.

Temperature Range: -40°C to 80°C (-40°F to +176°F)

Interface: I2C

Benefits: Senses humidity.

Price: $15

Links: Datasheet Python

MCP9808

Temperature Range: -55°C to +125°C (-67°F to +257°F)

Interface: I2c

Benefits: Can connect up to 8 different modules. High precision .0625°C

Price: $2

Links For Setup: Adafruit Tutorial
Some Python Libraries: Github