ESP8266 Temperature and Humidity Web Service

Скраћена веза:

After I successfuly tested HTTP server using Arduino and Ethernet Shield, I decided to try to accomplish the same thing using wireless connectivity. I decided to use ESP8266 on NodeMCU board. That is microcontroler with wireless interface all in one package, and quite low priced which makes it interesting for various purposes. I used the same temperature and humidity sensor DHT-22.

ESP8266 is supported within Arduino IDE which is big plus, as one can use the same development environment.

Soon I realized that popularity of this platform is well earned. It was very easy to set it up. […]
[ ... види цео чланак ... ]

Arduino Temperature and Humidity Web Service

Скраћена веза:

I needed simple device that is able to measure temperature and make it available for collecting that info from remote places via Internet. Arduino platform was the first thought and it ended up as expected: nice and simple.

For hardware I used Arduino UNO, Ethernet Shield and DHT22 Temperature and Humidity sensor.

Ethernet Shield pinpoint matches Arduino UNO so it is simply attached on top of it. It provides RJ45 connector for ethernet connection and SD card socket which I did not need for this small project.

All pins on Ethernet Shield are pass-through which means all Arduino pins are available on the this shield too. […]
[ ... види цео чланак ... ]

Baofeng LiIon charger modification

My idea was to be able to use this to charge Baofeng radio in various power conditions including in my car and this voltage was a problem. I noticed comments that charger should not be connected to higher voltage than 10 Volts. So I modded charger to fit higher voltage. baofeng-charger-mod

Iron Powder Toroid Cores Color Codes

Скраћена веза:

Iron Powder Toroid Cores part numbers are presented using format Tddd-m where dd is core diameter in tenths of inch and m is material grade. Also, cores are color coded to represent material grade.

Material grade defines frequency range core may be used for. There is no strict standard for coding but for informal purpose this table can be used.

Color Frequency
0 Tan/Tan 50 MHz – 350 MHz
1 Blue/Clear 150 kHz – 3 MHz
2 Red/Clear 250 kHz – 10 Mhz
3 Gray/Clear 20 kHz – 1 MHz
4 Blue/White 3 MHz – 40 MHz
6 Yellow /Clear 3 MHz – 40 MHz
7 White/Clear 1 MHz – 25 MHz
8 Orange/Clear 20 kHz – 1 MHz
10 Black/Clear 15 MHz – 100 MHz
12 Green/White 30 MHz – 250 MHz
15 Red/White 150 kHz – 3 MHz
17 Blue/Yellow 20 MHz – 200 MHz
42 Blue/Red 30 kHz – 80 kHz


[ ... види цео чланак ... ]

ЛЦД ЕСР тестер – мултиметар

Скраћена веза:


Замислите да можете да имате универзалним мерни инструмент који мери све: отпорност, капацитет, индуктивтет, диоде (обичне и зенер), транзисторе (биполарне, ФЕТ, МОСФЕТ, ЈФЕТ), тиристоре…

Отиђите у маштарији још даље: зар не би било сјајно да не морате уопште да се цимате него просто убодете компоненту у инструмент а он сам препозна шта сте уболи и измери карактеристике?

И поврх свега, да то лепо прегледно прикаже на екрану?

Луда идеја, али још је луђе да то у ствари постоји и то чак ради и више него што сте измаштали. А најлуђе је што је врло јефтино. Овакав тестер кошта око 15 до 20 долара, а мери малтене све што убодете у њега. […]
[ ... види цео чланак ... ]

APRS/Packet Radio audio cable for connecting Kenwood/Baofeng/Wouxun to Samsung SIII

Скраћена веза:

Here is a schematics of audio cable connecting Samsung SIII to Kenwood/Baofeng/Wouxun or other compatible radio.


Samsung SIII uses four pin 3.5 mm TRRX connector that differs than standard TRRX.

This cable can be used for APRS/Packet Radio. Most popular program for this purpose is APRSDroid. ALso can be used for Echolink, audio recordings, or similar usage.

You have to adjust volume output on both Samsung phone and radio to avoid distortions. Cell phone cannot control PTT of radio so you have to turn on VOX on radio to enable triggering TX when signal should be transmitted.

[ ... види цео чланак ... ]