I have just finished my OZ2CPu wattmeter,
The uncalibrated signal response is: +1/-1 dB from 1MHz to 450MHz. Input SWR will varry from 1.00 to 1.30, depending on input frequency. To make the SWR good, you need to assemble the input circuit correct and adjust the capacitor.
Input power range: -60 to +30dBm that is 1 nW to 1 Watt.
This instrument can be used and calibrated from 1 kHz and up to 500 MHz. It is possible to measure power relative all the way up to 900Mhz. A software routine can calibrate the 0dBm point at 5 different frequencies to make this instrument accurate within 0.5dBm !! The calibration data is stored in EEPROM so the instrument will remember all, also without power.
At frequencies above 300Mhz this instrument should not exceed inputs over +20dBm (100mW) to keep the good accuacy.
This is an easy way to power an highly brightness LED for 10 hours, some parts are recycled or was buy from ebay for 1$ or less …
– Solar panel 5v – 0.5A (ebay)
– 5V Mini USB 1A TP4056 Lithium Battery Charging Board (ebay)
– LM2596 DCDC Converter (ebay or dx.com)
– A Li-On 3.7V batteries (recycled from old phone)
– A photo-resistor, 10k pot meter, 1K resistor pull down, highly brightness 10mm LED (white warm), cables, and small box…
A lot of informations are available about ESP hardware over Internet … sometimes confusing, here is my experience’s about ESP8266 soldering and flashing, especially ESP-03 SMD version, first i use SMD adapters, Futurlec, 14 Pin SSOP Adapter has a perfect match, and are very cheap, the pin of SMD version didn’t match with standard pin header 2.54mm
My Baofeng charger has just burned …I didn’t want to buy a new one, it cost around 10$ … the batteries Baofeng is a Lion 3.7v 1500mAh, the good way is to replace the charger circuit with a another from Linear Technology, LTC4054-4.2, a resistor to set the charge current, one input capacitor, and a LED to look when the charge is over. Also, you can get the LTC4054 for free sample. Continue reading
Since I have discovered EasyIoT lib, i consider to redesign completely ArduiHome project. EasyIoT librarie support ESP8266 wifi , and NRF24L01+ shield, the wireless probe pcb will be use, with minor modifications.
I plan to use:
Temp/Humid sensor DHT22 for two bedrooms, and only Temp sensor for kitchen, bathroom, living-room, and maybe one sensor, Temp/Barometric Pressure for outside.
Also, somes security sensor’s like Carbon monoxide MQ7, and Gas Town MQ5/MQ6 will be add with use of SMS API from my mobile phone provider.
The server will run with EasyIoT server with a RaspberryPi2-1Gb, and a 4×20 LCD screen to display informations from sensor.