24
votes
Accepted
Is soil moisture sensor corrosion normal?
If you think about what is happening you have a very hostile environment for electronics (moisture - sometimes large amounts, soil PH and electrical current induced electrolysis)
The Hookup Guide for ...
- 34.5k
23
votes
Is soil moisture sensor corrosion normal?
Yes, this is normal for a DC drive configuration. You're effectively setting up an electrolysis experiment where the copper atoms on the positive electrode are being ionised, transported via the soil'...
- 330
9
votes
Using 5 volts on an mcp3008
First, lets check the characteristics of the MCP3008 again:
Single supply operation: V_dd = 2.7V to 5.5V
All Inputs and Outputs < V_dd + 0.6V (this should include V_ref)
200 ksps max. sampling ...
- 15.8k
9
votes
Looking for a starter kit for my 10 year old
There are a few things in addition to the pi itself that are required, and if you do not already have them, you would want a kit that includes them. Generally these are appropriately priced, but ...
- 58.5k
9
votes
ESP 8266 and Raspberry Pi communication without an Internet connection
You could have the Raspberry Pi behave like a WiFi access point (using hostapd and dnsmasq, introductory documentation from the Foundation is here) with a static IP and then have the ESP8266 join the ...
- 1,494
8
votes
Do I have to connect a resistor to my DHT22 humidity sensor?
It seems necessary for reliable readings. I started my project without pull up resistor and the humidity measurement started dropping down. It may start correctly but deterioate later. Since I was ...
- 181
8
votes
How to Connect 6 ultrasonic sensors to a raspberry pi?
The following code will scale to multiple sensors.
If you want all triggers to be at exactly the same time then connect the same GPIO to each of the triggers. Use that GPIO for the last sonar's ...
- 70.5k
8
votes
Is soil moisture sensor corrosion normal?
Yes, it's normal.
One electrode (the anode) will oxidise.
That said, it shouldn't happen so quickly. I guess you have the sensor powered constantly. That means you always enable corrosion.
What you ...
- 2,929
6
votes
Accepted
Difference between .../thermal_zone0/temp and .../thermal_zone0/subsystem/thermal_zone0/temp?
lrwxrwxrwx 1 root root 0 2016-02-19 22:24 thermal_zone0 -> ../../devices/virtual/thermal/thermal_zone0
lrwxrwxrwx 1 root root 0 2016-02-25 17:31 /sys/class/thermal/thermal_zone0/subsystem/...
- 58.6k
6
votes
Accepted
Connecting DS18B20 temperature sensor with RJ45 connector?
Connecting the DS18B20 to the Ethernet port would either not work or the effort to make it work (even if it was possible) would be excessive for someone starting out with a Raspberry Pi.
As you state,...
- 1,876
6
votes
Accepted
nutrient sensors for hydrophonics with raspberry
You need a TDS (Total Dissolved Solids) meter (aka EC/PPM meter) for measuring the nutrient content in your water, and you should also have a pH meter for maintaining a proper alkaline/acid level.
I ...
- 1,476
6
votes
Accepted
Scaling of digital reading of pressure sensor
Linear for the win!
y = (slope * x) + intercept is the classic linear formula, in your case, x=sensor, y=bars, so the formula becomes
bars = (slope * sensor) + intercept
... and you have two data ...
- 176
6
votes
Is joining NEO6MV2 module and RC 522 module together to Raspberry Pi possible?
Short answer YES.
The GPS module uses Serial = Yes you can do that with a Raspberry Pi
https://www.raspberrypi.org/documentation/configuration/uart.md
The RFID module uses SPI = Yes you can do that ...
- 983
6
votes
Accepted
How to connect multiple sensors to an rpi with the I2C?
I2C is a bus system and allows you to connect multiple sensors to the same pins. The master system (the Pi) lets the sensors know who should respond by placing that sensor's address on the bus.
In ...
- 70.5k
5
votes
How can I control Lego motors?
There is BrickPi+ helps you connect LEGO sensors and motors to the Raspberry Pi and replaces the MINDSTORMS Brick.
http://www.dexterindustries.com/brickpi/
- 51
5
votes
Sensor to detect water/liquid level
I found this Raspberry Pi water level meter - should answer the question is there water or not , but also a level indicator , like a measuring cup.
12" eTape Liquid Level Sensor
https://www.adafruit....
- 51
5
votes
Do I have to connect a resistor to my DHT22 humidity sensor?
I use a 10K pull-up from pin 2 (DATA) to pin 1 (VCC), and always use 3V3 to pin 1.
On 5V the sensor heats up a few degrees celsius. Also, pay attention to nearby heatsources (laptop, your breath, ...
- 264
5
votes
Sensor Question
The DS18B20 is a digital sensor using the Dallas 1-wire protocol.
If you just want to get figures to play with you could, as you say, connect an ADC and twiddle a pot.
However a simpler, and perhaps ...
- 70.5k
5
votes
Accepted
Is there a way to attach multiple serial port devices to a single raspberry pi?
You could:
utilize a couple of USB to serial adapters like this one.
you could use a microcontroller that has multiple serial ports (e.g. arduino mega) to gather the data and transfer it to the Pi, ...
- 34.5k
5
votes
Slot car races time recording
You can repeat this schematic, assigning a GPIO port for each lane.
The HAL sensor will require a magnet on the car, however, on my testing the magnetic field from the engine was enough to trigger ...
- 1,839
5
votes
Accepted
I want to use a common power supply to pi and sensors BME280 and BMA180 (sensor modules). Is it possible?
BME280 Adafruit I2C or SPI Temperature Humidity Pressure Sensor
First, I assume that this sensor module is referred to, not the bare sensor itself. There it reads:
So we made it easy for you to ...
- 15.8k
5
votes
Getting a CO2 sensor for Arduino to talk to Pi
To read this sensor on the Pi, you can use one of two methods.
First of all, you could have Arduino read the sensor and send the readings back to the Raspberry Pi, over a connection, either I2C, ...
- 4,489
5
votes
How to approximate room temperature in a better way
That's the main problem with the Enviro pHAT, and the SenseHAT for that matter - proximity to the Pi affecting results.
You're better off getting a Dallas 1-wire temperature sensor, preferably one ...
- 4,489
5
votes
Connecting 18B20 temperature sensor to Raspberry Pi 3
I've written a blog post detailing how to connect DS18b20 temperature sensors to a Pi here, but the short version is this:
The sensor has 3 pins:
Sense
3.3V
Ground
Which is which should be indicated ...
- 2,652
5
votes
Weather proofing a Pi
You've probably searched for a cover (as I just did), and didn't find anything that you could buy. That being the case, you must shift into "DIY Mode", and come up with your own solution. Before going ...
- 21.1k
5
votes
Powering a sensor using an external power supply board
Yes, (in general) in this case you should wire the ground terminal of all devices in your circuit together. This provides the necessary common ground reference voltage for them to interoperate.
Your ...
- 21.1k
5
votes
Accepted
Pi locking up trying to use rising/falling edge detection
Solution:
Add:
dtoverlay=gpio-no-irq
to /boot/config.txt.
Previously the kernel would automatically disable interrupts when you set one of rising/falling edge detection methods but that apparently ...
- 195
5
votes
Accepted
5v/12v power source/submersible water pump/RPI/relay. What kind of combination is suitable?
12V pump will require 12V PSU. 20LPM is a pretty reasonable flow rate for a small pump so your pump PSU will need to have enough power to drive the pump - check the max current draw on startup (which ...
- 66
4
votes
Accepted
LM35 long electric wire
The EE Stackexchange question/answers on LM35, pointed out by Steve Robillard, He linked this question, covers the subject of LM35 well. The answers indicate that several meters of cable (including ...
- 350
4
votes
Accepted
Where to find libraries for using existing popular sensors?
The source of sensor code is generally the same as the source of sensors themselves, i.e., the vendors. Not all of them supply such, and not all of them supply it in a 100 % compatible form. Note ...
- 58.5k
Only top scored, non community-wiki answers of a minimum length are eligible