[time-nuts] Holdover, RTC for Pi as NTP GPS source

David J Taylor david-taylor at blueyonder.co.uk
Wed Nov 1 12:07:43 EDT 2017

From: Mark Sims

I have an analytical balance that reads down to micrograms.   The weigh 
chamber is surrounded by three layers of IR absorbing glass so that radiated 
body heat does not induce convection currents in the air.   I worked on a 
balance that had nanogram resolution (mostly wishful thinking in that spec). 
It operated in a vacuum.  30 bit mass-to-digital converters are rather 
finicky beasties.

It does not take all that good of a temperature sensor to detect changes in 
room temperature due to body heat (or fetching a beer from the fridge in the 
next room).  You are basically a 100 watt space heater... even larger for 
the more corpulent folks.

Temperature is indeed the killer.  My best Raspberry Pis for time-keeping 
are RasPi-1 and RasPi-4, both of which are in an unheated cupboard not 
exposed to sunlight, on the north side of the house with indoor patch GPS 


SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor at blueyonder.co.uk
Twitter: @gm8arv 

More information about the time-nuts mailing list