Topic

arduino

A collection of 8 issues

Bluetooth Low Energy sensor

I have some ideas for a low power wireless sensor. I want something that will last more than a month on 2x rechargeable AA or AAA batteries. I first tried an esp8266 and then an esp32, but the boards I have all use 3-7mA in "deep sleep". This

Teensy 4.1 ethernet

I'm a fan of the Teensy [https://www.pjrc.com/teensy/] line of microcontrollers. I have a whole pile of them for various projects. When I saw that 4.1 was combining a 600MHz processor, 1MB ram, 8MB flash, and ethernet with ieee1588/ptp, I was excited. The

Wifi NTP server

I saw a thread about someone who wanted a low power NTP stratum 1 server that could run off of batteries and could be put somewhere without an internet connection. That had me wondering how an esp8266 would do in that situation. The hardware I put together was an esp8266

2 button keyboard

I wanted a simple keyboard with play and pause media keys to make it convenient to control my music. To handle the USB, I used a STM32F103 based "blue pill" board because they're cheap and easy to work with. First I put together a simple design

Navspark NTP stratum 0 clock

Project Goal I want to create a stratum 0 NTP clock that does not require soldering or any special hardware. It should only require a USB port and software. It should have at least 125 microsecond accuracy. How? I created a Navspark firmware to print a timestamp on the serial

Navspark UART/USB bridge

I created a program on the Navspark to send characters at 150 microsecond intervals and then received them on a PC. Below is a histogram of how long it took between characters: The red boxes are how long it took for the UART/USB bridge to send one character in

Navspark timer drift, #2

Second run, this time comparing the Navspark's internal CPU clock against the GPS time. Samples of both clocks are taken once per second, and the amount of time that has passed is calculated for both. The ideal CPU clock would be a perfectly horizontal line at 0.000

Navspark timer drift

The Navspark is a microcontroller with a GPS peripheral. It runs the GPS navigation/timing code as a binary-only library, and uses the Arduino IDE/environment. I have custom code printing timestamp markers on the Navspark, and I'm measuring the timestamp of the first byte of each line