Hardware

Glass reed switch and Fibaro Door/window Sensor (before I stumble on to Mysensors) if you have an electromagnetic door bell. Battery a bit expensive last more then a year with DS18B20 temperature sensor connected.

I'm currently in the process of trying to figure out why one of my battery powered nodes isn't working very well with a newly purchased NRF24L01+PA+LNA module. I've shielded it as described in earlier posts. There is plenty of pure power in the batteries. Just as in the case for @pkjjneal it works well only if I'm touching the antenna with a finger. I decided to look inside the antenna: [image: 1533729642840-dsc_1916-resized.jpg] As you see above, it starts with an antenna cable that leads to a half wave dipole (where the antenna element is of about 1/4 wave length) and there is a "sleeve balun" going back over the cable . I can find no ground plane though. The problem that I can see is that the antenna length is 27 mm where it should optimally be 28.8 mm. Now, if I remove the antenna completely my node works quite well. At least better than if I use the original antenna unmodified. If I insert a wire (DIY antenna made by a paper clip) extending 121 mm out of the antenna sockets forming a full wave length antenna things work great. I also modified the original antenna so that the antenna element becomes 28.8 mm. It works a bit better but it's far from perfect and communication errors are shown in the log. As the final test, I added a nice ground plane to the original antenna and now it works really perfect! [image: 1533729825900-dsc_1917-resized.jpg] So what can I learn from this? My test rig is an EasyPCB powered with batteries. I'm quite sure that my NRF24L01+PA+LNA module used in another scenario, for example connected to a Arduino Nano fed by a FTDI connector could actually work. It's because it would create a different environment. The antenna will work in relation to what it's connected to, shielding the grounding, and surrounding objects. Capacitive and inductive reactances are involved in mysterious ways. Anyway. My conclusion is that the two original antennas I have are not working very good. They obviously have the wrong length just a little bit, and I'd say that the the way the antenna is constructed with the sleeve balun and no ground plane, doesn't seem to work well. At least not here. I'll do some more experimenting with making my own antennas. Starting with taking apart an original antenna is not so bad, I can solder anything (solderable) onto the cable. Cheers! From wikipedia: Sleeve balun At VHF frequencies, a sleeve balun can also be built to remove feeder radiation. Another narrow-band design is to use a λ/4 length of metal pipe. The coaxial cable is placed inside the pipe; at one end the braid is wired to the pipe while at the other end no connection is made to the pipe. The balanced end of this balun is at the end where no connection is made to the pipe. The λ/4 conductor acts as a transformer, converting the zero impedance at the short to the braid into an infinite impedance at the open end. This infinite impedance at the open end of the pipe prevents current flowing into the outer coax formed by the outside of the inner coax shield and the pipe, forcing the current to remain in the inside coax.

@alowhum said in How to build up a sensor network: @dzjr sound like quite a plan. Why not directly connect the radio to your Raspberry Pi's GPIO pins? It's easy, and will save you an Arduino. This might be interesting to check for your irrigation needs: https://forum.mysensors.org/topic/9534/irrigation-controller/8 This might be interesting to check for your heater: https://forum.mysensors.org/topic/9421/safe-heating-with-mysensors-how-i-use-it-as-a-smart-thermostat Thank you for replying I will read the post's, and of course also use it during programming. The reason I use separate arduinos is that I want to set up the (rapsberry-Pi) domticz server in the house, in a central cabinet together with an RF-Link and a second MySensors gateway. Also, a Raspberry-Pi only has a limited number of GPIOs (eg wants to control 16 relays), and no analogue inputs, but I could still read that via an i2c multiplexer.

@jocke4u The moisture example could be used to detect leaks This project on openhardware: https://www.openhardware.io/view/534/Extremely-Simple-Arduino-Pro-Mini-LoRa-Water-Leak-Detector The following forum threads might be of interest: https://forum.mysensors.org/topic/1761/water-leak-detection https://forum.mysensors.org/topic/9070/water-leak-sensor https://forum.mysensors.org/topic/7736/water-leakage-sensor-using-thin-ribbon-cable-testing-reliability/ https://forum.mysensors.org/topic/4651/my-basement-flooding-alarm

@joaoabs said in Antenna for the RFM69: I'll be connecting a single core wire to act as an antenna to the RFM69 module. I could understand that it should be exactly 164.7mm long for 434Mhz. I could also understand that having the most accurate lenght makes all of the difference in the antenna efficiency. Now my question is: Since I'm going to solder it in the RFM69 hole, should I consider a few mm more, for the part that goes through the hole? In other words, is the 164.7mm the size from the PCB surface (and therefore needs a few mm extra to get into the hole), or what matters is having a 164.7mm wire soldered (and having some mm out in the other PCB surface). this exact antenna length is in an ideal world, but it's a good start. There are some points here that can also modify rf performance too https://forum.mysensors.org/post/91880 In short, pcb shape and its gnd size including battery (called the antenna gnd counterpoise, wider for 433mhz), antenna shape, bent or not, can have effects on bandwidth, efficiency etc. when you don't have tools for checking rf, you could empirically experiment by adding/removing few millimeters and see how it affects rssi for example. And better checking it with your node in final setup (in enclosure with battery, as it can also affect perf). This is fine tuning but sometimes depending on the node build it can improve range, then needs less TX power for same job, less TX power = less batt used.. and "greener" RF/less loud

yes you can change you go on switch press edit after a window that opens you go to Switch Type and you find motion safeguard

Hi @gabriel-vian, welcome to the MySensors community. Unless the data sheet explicitly mentions Arduino, there is no way to know from the data sheet. The best way is usually to search for the sensor's name in the Arduino Library Manager, or search for the sensor's name + "arduino library" using your favorite search engine. Adding "github" to the search can sometimes help.

@gal-shtendel Maybe you have to do some (internet) research on how the screens of smartphones or tablets work. something like this. Ok it's a little bit over the edge for a Arduino, but it gives some direction I hope. BR Boozz

@pa3gmi said in Pressure sensor board.: Yes it works :+1: I just beginning with it and I am almost 70. I will use the Nano and NRF24L01 and the Sensbender gateway for it. You're never too young to start programming ;-) Just come back when you need help!

@jlaraujo 3 or 4 if possible

@edsteve as per datasheet VGS Gate-Source Voltage - Continuous = ±8 V and Gate Threshold Voltage is Max 1,0V and Min 0,4V, this is working(conducting) voltage. So, according to above datasheet maximum voltage to gate can be ±8 V. About the resistor, you could also try 30K or 100K.

@easy the esp8266 radio is not compatible with the nrf24 radio. You can use the esp8266 as a gateway with sensors connected, but that will use wifi to connect to the rest of the world.

Hi @bignik, welcome to the forum! Using hardware serial should work. Did you use this? If so, what were the results? // Enable this if RS485 is connected to a hardware serial port //#define MY_RS485_HWSERIAL Serial1

@popsyann said in Battery life for Motion Sensor: When I load the motion sensor sketch, it start properly, finding the right "parent" and immediately after this, there is a flow of info going out of the Arduino+sensor, sending 0s or 1s, constantly (like if there was an issue with the interrupt process). And what I do not understand is that this (these) sensor(s) has(have) been working well for a while. Please search for sleep() function - it has changed the way it works at some stage in MySensors 2.* https://forum.mysensors.org/topic/1088/battery-powered-pir https://forum.mysensors.org/topic/5807/interrupt-and-sleep/26 https://forum.mysensors.org/topic/5552/pin-change-interrupt-not-firing-with-mysensors/28 Another reason could you that your PIR is not settling properly - this is why it sends out 1s and 0s to the GW. Try to insert sleep(20000); into void setup() at the end to settle the PIR

@ehome If you need a minimum range of 5-7m have you thought of radar? https://forum.mysensors.org/topic/3568/microwave-radar-module-as-pir-replacement/36

This is the AC light dimmer on the picture. I wonder how to use interrupts to detect cross-zero voltage and manage radio communication.

not sure about in sleep mode. But here is the sensor i am using. https://smile.amazon.com/gp/product/B00Q9YBIJI/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

@mainali said in INA219 DC Current Sensor: MySensor gw; I am building similar system. However, i am facing a lot of difficulties to make the ACS712 working. I have tried your code as well without success. The effective value of the current is always 0 mA even if the light is ON. For the moment, i am testing with 5V current and i switch on a LED. maybe the current is too low to make working my 20A ACS712? If anyone has some ideas, it will be very greatful :) Thanks a lot.

@yveaux thank you for reply, i dont have any arduino with led to test this :) all boards are in use and without led may be i'll order few to test this at some stage.