#365 Is Power over Ethernet (POE) on the ESP32 any good? (New TTGO and Olimex boards available)

how should we connect devices to our home network wireless or wired do these new boards from ttgo and olimex change anything interesting questions let's have a closer look great youtubers here is the guy with the swiss accent with a new episode and fresh ideas around sensors and microcontrollers remember if you subscribe you will always sit in the first row we all know wireless iot devices are cool but they have some drawbacks this is why we want to look at the alternative wired iot devices what are the pros and cons of both technologies which cables do i have to use for my home network and why what do i have to know if i want to crimp my own ethernet cables how does the esp32 support ethernet and which boards are available what is the downside of using ethernet on the esp32 how complicated is it to change a wireless sketch to a wired one of course we create an example to test if it works as an mqtt sensor and actuator wireless is fascinating to me since i was young it has many advantages like no cables to deploy and the flexibility to freely move everywhere in the range of the device but wireless also has disadvantages because information moves through the air it is prone to hacking and interference a proof all modern armies have an electronic warfare department its throughput is limited because all devices within the reach have to share the same channels in addition the faster a connection the more bandwidth it needs and the more power we need for a transmission if you want to know more about wireless communication watch videos number 219 and 221 wired connections are simpler faster and more energy efficient for short ranges because they use a star topology they have fewer resources to share wired connections are hard to hack if you do not have physical access for me as a rule of thumb i use wired connections where possible my pc and my raspberry server are connected with ethernet cables for example there is another cabling possibility for home automation two wire buses like rs-485 a few years ago i probably would have thought about using such a bus for my home but with the standardization and the rise of ethernet those buses became less and less attractive so in this video i will concentrate on ethernet the decision for that video was sparked by this port from ttgo it contains an esp32 module and an ethernet connector we will later see why it has this sticker by the way olimex also has new boards in the shop what does a typical maker have to know about ethernet here are the most important things it is a very standardized cable connection that uses rj45 connectors on both ends not like power cables which have different connectors on both sides the cables contain four cable pairs and the newer ones also have shielding against interferences the pairs have different colors orange green blue and brown one wire of a pair has a solid color the other one not two different wire diagrams exist mainly to confuse us flip a coin on which one to use and stick with it at least for both connectors on one cable because it does not matter these days all wires are connected straight from one side to the other not crossed in the old days we had to use crossed patch cables for specific purposes today the routers and switches have auto sensing and adapt their pins like many other things ethernet was invented at xerox park in 1973 and of course i have to mention that digital equipment corporation or tech one of my early employers was responsible for its fast distribution in the 1900s and 80s against ibm's token ring concept by the way back then the speeds were low and the cables therefore simple when speeds increased cables had to become more sophisticated to get some order they started to categorize them using numbers at the time of making this video cat 6 cat 6a and cat 7 cables are in focus as we see on the list cut one to five and cut eight cables exist but they are not important cut one to five are too slow and cut eight is too expensive and not needed most of us will use 1 to 10 gigabits networks for the next years the difference between cat 6 and 7 is the transmission speed they support the diameter and the price cut 6 is suitable for 1 gigabit per second cut 7 for 10 gigabit per second you also get cut 6a as a compromise but the uplift to cut 7 is not significant so cat 7 is the right choice for new cabling fortunately ethernet connections are backward compatible this means you can connect a slow device to a fast device without problems even if you connect two fast devices with an old cable they will work just slower so ethernet is one of the more stable standards and it is here to stay we can depend on it you can buy pre-fabricated cables but can also crimp your own just some recommendations buy a good crimper and a cheap test device to check the wiring of the cable before you use them like that you are sure that the sequence is correct and all wires are connected and by the right connectors that match the category of the cable you want to crimp they are different even if they are compatible ethernet offers another great feature power over internet or poe if you want to brush up you know how on that topic i suggest you watch video number 276 right after this one in a nutshell we can use the ethernet cable to power our devices which is extremely useful we do not need a power supply for each device and no second cable modern routers like mine support poe the standard voltage is 48 volts and it provides enough power for most applications these 48 volts are by the way probably the reason for that danger sticker in the area of the poe parts and now we are back to the esp32 board in addition to a standard vroom module it has the needed circuit for ethernet and poe it also has an sd card reader if you need one but attention it does not have a usb to serial chip on board this means that you either have to order the additional converter or build a cable for your standard adapter here is the pinout please be aware that the programming connector does not have the standard pin distance of 2.54 millimeters its distance is two millimeters so i suggest ordering one adapter with your first board this usb-c socket is only for power which is not needed in my case because power comes via the ethernet cable but how does ethernet work on the esp32 it uses the wi-fi commands very strange indeed but it is a good idea as we later will see you do not need to change your sketch a lot as a demonstrator i created an example of a typical application where a bme 280 transmits its readings via mqtt the device also waits for mqtt commands and switches an led on and off what are the changes from a wi-fi enabled sketch we have to include this library and to add the pin definitions for the chip and here we see a function that shows us what happens and also shows us the ip address in setup we have to call this function and start the ethernet with all pins from before the loop stays more or less the same where did i get the sketch from i combined a few sources and did some tests till it worked unfortunately ethernet on the esp32 is not used a lot up till now maybe this will change now the speed on the cable is 100 megabits per second maximum which is for sure no limit for an iot device and what about power consumption and deep sleep i have to tell you i don't care about that in this setup because we have enough energy coming through the cable and do not need deep sleep a warning i tried to use ble with ethernet unfortunately it did not work i did not investigate why maybe you know another important remark comparing the pins of the breakout connector with a priority pin list of my last video we see that we only have six freely usable pins and worse we do not have the standard i square c pins available fortunately the adafruit library for the bme 280 supports free i-square-c pin assignment looking at the olimex diagram of a similar board we see that ethernet uses eight pins of the esp32 also the two standard i-square-c pins hollymax by the way uses the lan 8710 chip and ttco the 8720 was it worthwhile for ttgo and olimex to create new ethernet ports what do you think summarized wired connections have three main advantages over wireless networks privacy because it's not easy to hack them speed because it's easier to reach high speeds on a wire than over the air and because the connections do not need to share the same resources energy over a short distance wired communication need less energy and with poe we can power our device without problems wireless connections are far more flexible and mobile ethernet cables are categorized today i suggest using cat 7 cables for new projects you can either buy a ready-made or crimp your own cables select the right connectors and a good crimper and test all cables before you use them fortunately the esp32 natively supports ethernet and a arduino library exists unfortunately the ethernet chip needs eight gpio pins which leaves us with 12 usable pins at the breakout connector only six of them belong to the priority list another four are input only pins gpio2 and 12 are strapping pins with special functions an example sketch connects to the mqtt server via cable transmits a few sensor readings and waits for commands to switch an led or a relay ethernet uses the wifi commands strange to read but very useful because we do not have to adapt our sketches too much because we cannot use the standard i square c pins we have to tweak some libraries if they do not support free pin assignment all in all a valid alternative for fixed devices in home automation as always you find all the relevant links in the description i hope this video was useful or at least interesting for you if true please consider supporting the channel to secure its future existence thank you bye

Channel: Andreas Spiess

Views: 111,934

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Id: v8JodmdxIKU

Length: 13min 20sec (800 seconds)

Published: Sun Dec 13 2020