A follow on book to “VSWR and Impedance matching ” has been published and is available on Amazon entitled ” Practical Impedance matching”, This book adds many more topics to the contents of the earlier book. Please access it at:
https://www.amazon.com/Practical-Impedance-Matching-techniqes-electronic/dp/198666662X/ref=sr_1_1?dchild=1&keywords=practical+impedance+matching+ain+rehman&qid=1587492727&sr=8-1 . Please visit the Signal Processing Group Inc., website for more information.
Interesting project completed that uses a ESP-01 to detect sensor outputs and sends the results to the cloud server. The sensor output may have to be conditioned somewhat if the least expensive ESP device has to be used. In any case, code was written using javascript to talk to the server. So the system is simple at this point. The ESP – 01 sends the results of the measurement to the cloud server and the javascript along with HTML can be accessed via a PC or a IPhone to read the data and generally communicate with the cloud server. The system is working well and further refinements are planned and will be reported. Please visit the Signal Processing Group Inc., website for more info.
This work was done using an ESP8266 ESP-01 device with pin2 of the device connected to a sensor output ( conditioned). The software that drives the ESP-01 was written to send the sensor output to a cloud server. The work took a little time to get everything sorted out but ultimately it worked well. Now the ESP-01 connects to the local gateway and via that gateway connects to the cloud server. A webpage with some javascript connects to the server when reading the information written there by the ESP-01. Please visit the Signal Processing Group Inc. website for more information and articles of interest.
Further to our posts on the ESP-01 we now have developed a ESP-01 based star system model where we have a central server and soft access point that generates a WiFi network . We have clients that are also based on other ESP-01 modules that can connect to this network ( as many as needed to a reasonable extent). This system now allows us to build a star system of WiFi modules that can be used to sense/control devices connected to the individual modules. More to follow. Please visit the Signal Processing Group Inc. website for more information about us and other articles of interest.
We continue to develop more and more applications using the ESP-01. Connect to the Network and become an access point for other clients to connect to. A key part of this understanding was the successful inclusion of the header file ESP8266Wifi.h. This file was creating errors in program compilation until we finally understood how to stop these from occurring. Once that was done the process of developing applications became a little easier. The issue we are grappling with now is the provision of the power supply in the case of a standalone battery powered application. We will be reporting on that in subsequent posts. Please visit the Signal Processing Group Inc. website for more technical information.
Here is another interesting finding from our experiments with the ESP-01. We got stuck on a number of files whenever the file had ESP8266WiFi.h in it. While compiling the error was “Error compiling for board generic ESP8266 Module”, After some frustrating days we found ONE fix that seemed to work. This is to go to the “tools” menu in the Arduino IDE and make sure that the Debug port is “Serial” and the debug level is “WiFi”. At least that seemed to work for us. More ESP-01 blog posts to come as we work our way to a better understanding of this product. Please visit the Signal Processing Inc. website for more technical info.
The ESP-01 is a very small RF / uC module capable of WiFi operation standalone, or as part of an embedded system. It is very popular and we decided to take a look at it and it proved a fascinating study so far.
However, it is not easy to use and will frustrate a person unless that person has a lot of patience. There is a lot information about it available on the web, both textual and Video but in most cases this can only be used peripherally as the ESP-01 can be difficult to manage and use.
The software component of this product is the Arduino IDE which is a big help. Here are our observations after a few days of experimenting with the ESP – 01. (1). You have to get a good programmer so that programming will not be that painful. I have been using a standard programmer, i.e. a USB to TTL ( and vice versa) device that is both cheap and freely available. See the picture below.
However it is important to modify its physical construction somewhat. (a) Connect a switch between the GPIO0 pin and ground because the programming will require that configuration and the programmer does not provide it. (2) Connect the CH_PD pin to VCC. (3) Connect a pushbutton switch from RESET to GND. This is important. When programming the GPIO0 switch has to be in the GND position and the RESET pin must be pulsed.
Beyond this the programming is quite painful and one must be prepared for many failures and frustrating days. What we want to do is try to journal as much as we can in this blog to help.
More in following posts. Please visit the the Signal Processing Group Inc. website for more technical info and contact procedures.
