py programs are installed in the /pi directory but when I run the test program I get the following results: The full results of these tests will be published in November, 2014 in Raspberry Pi Geek magazine. Project Curacao has not had good luck with the DS1307. The DS3231 is the only temperature compensated device and the MCP79400 is the only DS1307 in Project Curacaoĭevice that has a programmable trim. on chip trim for +/-127 PPM – it is rock solid at 4 PPM at this point) DS3231 – Our first glance results yield the following values: For example, losing 1 second per day is a drift of 11.5 PPM while 1 PPM is a drift of 0.0864 seconds per day. We are measuring the results in PPM (Parts Per Million). Based on our testing, we have now selected the DS3231 to replace the flakey DS1307. These releases are part of a project to measure accuracy of a number of Real Time Clocks (RTC) and select one to upgrade the Project Curacao DS1307 as there is a problem with that clock in the project. There are python libraries for the following devices on the SwitchDoc Labs Github: I’ve written up a brief article on each device. My Raspberry Pi based RTC tester just keeps humming along storing all the results into a MySQL database ready to be analyzed and graphed for my next column in Raspberry Pi Geek magazine. My goal is to reach 3,000,000 by the weekend and then write up the results. I have now completed over 2,600,000 seconds (30 days) of testing. This project was designed to select a new I2C RTC for Project Curacao and to test the accuracy of a set of these clocks. I have now released four libraries for I2C Real Time Clocks (RTC) for the Raspberry Pi. For example, a Raspberry Pi being sent up in a balloon or a Pi working in the remote caribbean, like Project Curacao. A realtime clock is necessary for any project requiring accurate time keeping especially when you don’t always have an Internet connection. An Arduino often requires a RTC especially if it needs to sleep (shutting down the internal timer based clock). NTP will keep your clock close if you are connected. Not connected to the Internet (if you care what time it is!). Four RTCs - DS1307, PCF8563, DS3231, MCP79400 Real Time Clock Python Libraries For Raspberry Pi – DS1307, DS3231, PCF8563, MCP79400 – Reviews/Resultsįor devices like the Raspberry Pi, a Real Time Clock (RTC) is needed anytime the device is Four RTCs – DS1307, PCF8563, DS3231, MCP79400
0 Comments
Leave a Reply. |