Contact: info@pavlin.si
Archive for the ‘Ham’ Category.
This is short tutorial how to send data from sensor connected to The Things Network via LoRaWAN to Weather Underground. I will use Scidrom air quality sensor whic I developed for students in local school. Just a quick reminder the “AQ” sensor detects PM10, PM2,5 particles, air pressure, temperature and humidity and solar radiation in visible in UV spectrum. More details are available in older post.
“Special offer” came out for 5GHz antenna. It was posted on Polish web store Interprojekt, where I sometimes buy some equipment for long range WiFi point-to-point links.
The antenna came well packed in carton with additional box for the feed. The grids were separated with paper to avoid scratches during transport.
Here are instructions for outdoor UV index and ambient light sensor.
The solar radiation shield is a low cost DIY device to protect temperature, relative humidity and other sensors from the weather, while shielding them from the sun for highest accuracy. Provided here are instructions and files. It require some CNC machinig, but then it could be assembled in minutes. It is made from plant pot saucers.
Two PCBs from earlier projects were used in this project:
Finished particle sensor in housing, ready for the TTN
This simple Helical Antenna can be used for most LoRa (and other small wireless device) applications, where space constraints exist. The construction is simple, made from wound solid Ag plated copper wire taken from piece of coaxial cable.
Helical axial antenna for 868MHz
Two options how to use this antenna on the PCB modules
Continue reading ‘Small “rubber-ducky” helical antenna for 868MHz’ »
This is simple antenna for 868MHz built in 5…10 minutes. Take about 10cm of RG214, a plate of PCB with the copper at one (or both) sides. Remove the coax shield and inner dielectric on one side in length of about 85mm. You will cut this to proper length during SWR measurements.
Simple antenna made with piece of coax and piece of old PCB.
Continue reading ‘Quick and dirty 868MHz antenna in 5 minutes’ »
This is description of coaxial collinear antenna for 868MHz applications. I designed this for Lorawan gateway.
Antenna tested with lorawan gateway
Continue reading ‘Collinear antenna for 868MHz Lorawan Gateway’ »
I will descvribe here the USB interface between the redio station and the computer which I recently developed and tested. This post is a continuation of the first part, where I described a simple interface for controlling two digital lines using the USB / Serial Converter, where I presented simple interface to control two digital signals (e.g. PTT and CW). This time I will describe an interface that combines more functions:
I had some implementation issues with the microcontrollers and USB virtual com ports, which I have described in detail in the previous contribution, I decided it’s better using the tested solutions. The block diagram of the interface is swhown in following picture:
Block diagram of the interface
Continue reading ‘Tiny, isolated USB to Xcvr interface (PTT, Audio, CAT, …)’ »
In this post, I will first introduce some of the basic technical background of the control of the transmit signal (PTT) and other signals (eg CW or linear activation). The second part will describe the interface development and the final product.
Standard DB9 male connector