Dan's notes (Page 6)

More issues

RK3328 based NTP server

I got a ROC-RK3328-CC [https://libre.computer/products/boards/roc-rk3328-cc/] SBC because it has true gigabit ethernet, emmc, and USB3. These are all better I/O options than the latest Raspberry Pi 3 B+. I put a SATA hard drive in a USB3 adapter and connected it. The SBC froze

TL-MR3020 NTP server, part 2

Part 1 [https://blog.dan.drown.org/mr3020-ntp-server/] was about the hardware, now for the software Step 1: pps-gpio-poll package This architecture doesn't support device tree yet, so it has a special pps driver. The repo for the driver package is at https://github.com/mlichvar/openwrt-pps-gpio-poll I

TL-MR3020 NTP server

I have a small travel router that I no longer use, and I wanted to turn it into a NTP server. The hardware is pretty well documented here: https://openwrt.org/toh/tp-link/tl-mr3020 For the PPS signal input into the router, I need a GPIO [https://en.wikipedia.org/

Sharp Wireless Weather Station, part 4

part 1 [https://blog.dan.drown.org/sharp-wireless-weather-station/], part 2 [https://blog.dan.drown.org/sharp-wireless-weather-station-2/], part 3 [https://blog.dan.drown.org/sharp-wireless-weather-station-3/] Turn the receiver off between messages To save power and cpu, I wanted to turn the RTL-SDR off between messages. Because the next message comes at

GPS module measurements, part 3

GPS module comparison: NEO-7N vs NEO-M8N

Sharp Wireless Weather Station, part 3

part 1 [https://blog.dan.drown.org/sharp-wireless-weather-station/], part 2 [https://blog.dan.drown.org/sharp-wireless-weather-station-2/], part 4 [https://blog.dan.drown.org/sharp-wireless-weather-station-part-4/] Reverse engineering the CRC In looking at the crc field, I tried a number of different things. rtl_433 crc functions First, I tried the crc7,

Sharp Wireless Weather Station, part 2

part 1 [https://blog.dan.drown.org/sharp-wireless-weather-station/], part 3 [https://blog.dan.drown.org/sharp-wireless-weather-station-3/], part 4 [https://blog.dan.drown.org/sharp-wireless-weather-station-part-4/] rtl_433 The rtl_433 [https://github.com/merbanan/rtl_433] project has support for decoding a bunch of different weather station devices. Unfortunately, it doesn&

Sharp Wireless Weather Station, part 1

What is the goal? I have a weather station with a wireless temperature/humidity sensor. Instead of looking at the LCD on the wall, I'd like to have that data on my phone. A graph of historical data would be nice as well. What am I starting with?

GPS module measurements, part 2

After the previous tests [https://blog.dan.drown.org/gps-module-measurements/], I ordered another GPS antenna to improve the signal conditions. They're just the cheap puck style antennas with SMA connectors ($10 on Amazon), and I've put them on my windowsill. There's something wrong with

GPS module measurements

Starting point I got a u-blox NEO-6M and I wanted to compare it to my NS-T. Since I don't have a frequency counter, I decided to try creating one myself. The hardware I have on hand is a 72MHz STM32 devboard. I used the input capture hardware on