Playing with temperature sensors on breadboard is cool, but usually, if one has more than one sensor, one likes to get some distance between them.
These are no scientific tests, but in my real world application, LM35 likes shorter cables. The shorter the better, or it will get large fluctuations in measurements.
A cable about 3 meters is as long as I would go. Cable length of 5 meters got me into trouble. Consecutive readings did vary in more than 5 degrees. Not good.
Cables as long as 1 or 2 meters are good enough, but to get a constant reading from a sensor, I discard the first reading, as it seems to be the most inaccurate one, then read several times and get an average.
As far as I tested, there was no difference if I used a better cable. So a standard 4 wire 0.22mm signalization cable is what I had and used. Do 3 wire cables exist?
DS18B20 works with longer cables. As it is one wire device, only two wires are needed 🙂
A test with a 100 meters of cable was unsuccessful, but about 20 meters works well enough. Sometimes I get a false reading of -127.0 degrees Celsius, but it seems that I can get this on 3 meter cable as frequently as on 20+ meter cable.
At least DS18B20 also works in star configuration, so multiple wires can start from one point.
I used 2-wire telephone cable here.
So right now I have an Arduino board with 6 temperature sensors –
3 x LM35 with 1, 1.5 and 2 meter cables and 3 x DS18B20 with 2, 10+ and 20+ meter cables.
Hi, I’m interested in your experience, If I well understood, with the DS18B20, you succeed in reading the T° with the sensor at 20+ meter length of your board with a simple phone cable ?
In that way, can I imagine that any 1-wire captor will be able to be read at about 20 meters far away from the board.
My project is to put some arduino in my house to collect captor data and I’m in the phase of testing captors to ensure max length from the board to the captor in order to know if I have to put an arduino in each room or at each floor only…
Thanks for your feedback, best regards, Jérôme.
I do have one DS18B20 connected with a 20+ meter cable. Works reliably. At least I can see no difference between 20m cable and 50 cm cable. It is not a phone cable actually. I did get it for connecting security system sensors, but it can also be used for telephone cabling. The price class was about the same and the cable is almost the same. Actually CAT5e or better should be a lot better cable. I’m planning to add some more sensors and using CAT5e this time. If You look at linkusb then 1000 feet (approx 300m) on cat5 should be doable. Maybe not with straight connection to arduino, but doable.
Maybe we can solve the problem of the cable with a thicker cable. I will do a test in my house today. I will you comment my results.
For longer distances, you can use SMT160 sensor.
Although if you supply sensors with adjacent power supply, you can get a 100m cable length!
پروژه هاي الکترونيک کنترل مانيتورينگ اتوماسيون صنعتيارائه انواع پروژه هاي صنعتي آزمايشگاهي دانشگاهي تحقيقاتيhttp://automasys.wordpress.comانواع ميکروکنترلرهاي ميکروچيپ اتمل اينتل فيليپسAVR ARM LPC STM32 PIC dsPIC 8051 8086 z80انواع اينترفيس و پروتکل هاARM AVR PIC MicroController Electronic Project GPRS GSM USB BlueTooth Ethernet Network CAN I2C SPI RS485 Automation PLC پروژه الکترونيک ميکروکنترلر آرم 8051 اتمل فيليپس ميکروچيپ Interface اينترفيس ويژوال استاديو Visual Studio 2010 C# VB.Net Protel DXP Altium Eagle PCB SPICE PSPICE HSPICE ADS OrCAD Silvaco
for longer wire for lm35 u cam use lowpass filter (L-C) to gate ADC
or
u can use one capacitor (10uf) to gate ADC and GND
u can longer wire 3m or more
ابا استفاده کردن از یک فیلتر پایینگذر
میتوان طول سیم سنسور را تا چندین متر افزایش داد
همچنین میتوان از یک خازن ده میکروفاراد که یک سر آن به زمین وسر دیگر به ورودی ای دی سی متصل است استفاده کرد