Enthalpy change in a cyclic process is zero. In a spontaneous process, change in entropy will not be less in the direction of spontaneity. Change in enthalpy is equal to the energy supplied as heat at constant pressure. H = U+PV dS = d/T Its unit is KiloJoules/mole. It is the amount of heat transferred reversibly in and out of the system at a given temperature. It is the sum of internal energy and product of PV work. It is the measurement of the disorderness of a system. This lost energy is called the ’entropy’.Įnthalpy Entropy It is a measurement of energy. The concept of entropy develops from the fact that for energy to be converted to work, some dissipations must occur. This idea comes from the concept that heat always flows from hot to cold regions spontaneously which is equal to the entropy change. The term entropy was introduced by the scientist Rudolf Clausius in 1850. It is an important quantity because most of the reactions occur at constant pressure and it is used to measure the heat of a reaction. Enthalpy tells us how much heat is added or removed from the system. The word enthalpy means ‘total heat content’. The term enthalpy was introduced by a Dutch Scientist, Heike Kamerlingh Onnes in 1909. In thermodynamics, the change in enthalpy and entropy can be measured rather than their absolute values. Enthalpy (H) of a thermodynamic system is an energy-like state function property that is equal to the total internal energy (U) and pressure-volume (PV) work whereas entropy is an intrinsic disorderness of a system under certain conditions.
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If the stick lies in front of you, the USB-Port facing to the left, Pin 1 is the one on the top right of the 10 Pin programming header.Whilst i understand that the CC2531 are not recommended, nowhere do any of the docs say they are unsupported / do not work…infact, the CC2531 adapters are listed as being known working radios You only need to connect these four Pins on the CC2531: Note, that on the wemos/ESP side, D6 ( DD_I ) and D4 ( DD_O ) are connected together and go to Pin 4 ( DD / Debug Data ) on the CC2531 debug port. These small pins are really pretty fragile! So take care when not using the small spaced connector cable. I've seen a couple of people destroy their debug port / breaking pins by handling it too rough. In order to connect your wires, you can either use the linked Debugger Cable or carefully connect your SMD probes to the tiny pins. In contrast to your common breadboard / connector, the debug port on the CC2531 has a smaller spacing of 1mm. Since the ESP uses 3.3v, you don't need a voltage divider! Now, get some (actually 5) jumper wires and connect your ESP board to the debug port of your CC2531 adapter. Once you've compiled and uploaded the CCLib_proxy to your wemos d1 mini board, unplug it from the USB bus. Once you have modified the code, compile and upload it. you probably don't have to change the delay. this is needed for the ESP8266 / wemos d1 mini / nodeMCU to get it working line 98 and increase the initial value (50) to 1000:Īgain. Then, look for the first delay() at approx. Pinout configuration (Configured for wemos D1 mini) int CC_RST = D5 After more than an hour experimenting I found this configuration to be working flawlessly out of the box. This is important, since it makes a big difference which Pins you use! I was not able to make the programmer work when I initially used other pins. Specify the correct Pins for the ESP8266 / Wemos D1 mini If you have downloaded the CCLib_proxy.ino linked above you can skip the following code modification. I have uploaded my modified version of the arduino sketch to hackaday.io. Open the CCLib_proxy.ino from CCLib/Arduino/CCLib/Examples/CCLib_proxy Install the Arduino/CCLib library to your arduino IDE Now, install the required python modules by typing: Once you've downloaded/unzipped CCLib, open a terminal and change directory into the Python folder You will also need Python 2.7 or later installed to your system. Just save the file and you are good to go. Scroll to the very bottom of the file and remove the second line from the bottom. hex file in a text editor of your choice. Otherwise you will not be able to flash it! When using the arduino based CCLib_proxy debugger/programmer as described here, the custom firmware (CC2531ZNP-Prod_20181119.zip) from Koen Kanters, has to be modified. If you download the CC2531ZNP-Prod.hex from here ( hackaday.io) you do not have to modify the file! Hence I have attached them to this project. I installed and verified both versions to be working. On Linux, you can simply download it by typing wget https:/ //kirovilya /files/master /CC2531ZNP-Pro-Secure_LinkKeyJoin_mod.hex This is the firmware for your custom, ESP8266 based programmer I assume you are familiar with the Arduino IDE and have it installed on your PC. update: new Z-Stack-Firmware with group support and increased stability from Kkoenk available: Once you have your stick up and running, see also my other project on how to add an antenna socket for increased range: CC2531 USB Adapter Antenna mod ) and use it as remote ZigBee to MQTT gateway which can be placed in a suitable location in order to get a better range. Once you have the correct firmware installed, you can use it to replace most if not all of your proprietary ZigBee gateways and use it to control a variety of different devices, such as lamps, temperature sensors, switches, etc.ĭepending on your home automation system, you can either use the stick directly with an appropriate adapter or have it plugged into a raspberry pi (or orange pi, etc. Since it has a programming port, you can upload/install a custom firmware which acts as a zigbee concentrator. You can get these for a few dollars from aliexpress or ebay. The CC2531 is a complete ZigBee / IEEE 802.15.4 transceiver bundled with an 8051 CPU and an USB interface on one chip. So we booked a condominium in Stateline, Nevada, just a few blocks from the intersection of Nevada Highway 207 and US Highway 50. With that as our homebase, we resolved to re-explore South Lake Tahoe and the casinos in Stateline, find new hiking trails and discover new restaurants and nightlife. If you don’t have a timeshare week to trade, take a look at the slower season rates for overnight stays using KAYAK or, Vacation Rentals by Owner (VRBO) or AirBnB. Older, relatively inexpensive but nice motels lie just northeast of Stateline and Lake Tahoe boulevards. From our condo, or other hostelries in that area, you can walk to many of the attractions, morning to evening. We found that you can discover a lot just by walking. A morning several-mile hike from our condominium in Stateline revealed a host of nice motels on the California border, and new restaurant gems such as Idle Hour wine tasting, with cheese fondue and other interesting creations and a spectacular view looking northeast up Lake Tahoe’s shore. The Beach House Restaurant on Lakeside Beach offers spectacular views looking up the lake, and a variety of tasty, bistro food. We also found Toulouse Restaurant just off the lake, featuring a “touch of New Orleans” (featuring shrimp gumbo, shrimp and grits, oysters and more) with wonderful food even if holiday service was a bit stressed. Later in the week we would discover the town’s best bloody marys (subjective, yes), with either omelets for breakfast or calamari for lunch at Artemis Lakeside Cafe on Ski Run Boulevard. Just steps away is a fine full-service restaurant on the lake, the Riva Grill, with the best fish and chips meal we’ve tasted in a long time and other savory options. Late in the week, we realized the Chart House Restaurant was just a mile up Highway 207, and spouse Susan found it featured a 4 to 6 pm happy hour. With a host of tempting classy appetizers from $4 to $8 and discounted drinks in a white-table-cloth part of the restaurant, it was a hit for an upscale but inexpensive outing. Seeking memorable but budget-friendly nighttime activities, Susan opted for Magic Fusion, two magicians wowing crowds at The Loft Theater, with a 1½ hour magic show entertaining for both adults and children.
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