Monitoring Project - Introduction

The pendulum clock in Trinity College, Cambridge was installed in 1910. It is remarkably accurate, known to be better than one second per month. In 2009 a system was installed to monitor the "going". The work was done as part of a 4th year MEng project at the Engineering Department. A sensor on the pendulum detects the going of the clock, which is compared to the accurate time signal from a GPS receiver. For an entirely mechanical clock the accuracy is remarkable. Watch the clock strike twelve or hear it strike twelve at Singing from the Towers . Follow @clockkeeper on twitter. Today's and yesterday's weather in Cambridge, including wind. Here is a graph for the last 30 days of drift

A barometric compensator was installed at clock change - midnight 28 March 2010.
The clock is regulated as infrequently as possible so as to stay within +/- 5 seconds of the correct time. This enables the steady-state physics of the clock to be examined without unnecessary interference. The black dots • indicate that there is a comment relating to the time indicated. Blue arrows pointing down indicate that an adjustment was made to the Going of the clock by removing weights from the pendulum. Red arrows up indicate addition of weights to speed the clock up.

date [time GMT]Clock Diary
10 Feb 2016 [21:33:15]winding by the Combustion Group: Philip Sitte, Anna-Maria Kypraiou, Andrea Giusti, Harsha, Colleen Stuart, Patton Allison, Pedro Magalhaes de Oliveira, Jenni Sidey @jennimsidey  
03 Feb 2016 [18:58:28]winding with Felicity Lamacraft, Celeste Lamacraft, Arrate Molina and Austen Lamacraft - all very excitable inversely proportional to age!  
27 Jan 2016 [17:30:00]winding ably assisted by Terry Black from Windfall Films - all for a documentary about the first television broadcast in 1936. Thanks also to Peter Gauvain behind the camera and Henry Hocking on sound  
20 Jan 2016 [11:23:23]Thanks to Peter Windmill for winding at the last minute - and for correcting the bells that went out of synch  
12 Jan 2016 [23:07:48]winding after Fairhavens with Stephen Watson - Emmanuel College  
05 Jan 2016 [18:11:01]winding by Andy Jude and Hilary Costello - first for 2016  
29 Dec 2015 [17:43:36]Winders: Julian Cooling, Karen Bass and Chris Nickolaus, last wind of 2015.  
22 Dec 2015 [21:27:23]Clock winding by Deah Dhaliwal, Anya Dhaliwal and Sam Dhaliwal, shown the ropes by Hilary Costello - thanks!  
15 Dec 2015 [21:00:00]Winding by Rick Lupton - thanks!  
08 Dec 2015 [22:39:28]after three pints of Pegasus from the Maypole (in own glasses) winding by Ben Sparks @sparksmaths and Seb Falk @seb_falk  
01 Dec 2015 [09:08:34]Nick Denyer girding his loins for essay marking  
30 Nov 2015 [16:13:20]visit by Owen Ryder and Peter Stitt from Cummins Turbo - true mechanical engineers!  
23 Nov 2015 [21:36:40]yet more, from Peterhouse, Trinity and other colleges (Queens' perhaps?) Basil Mustafa, Ethan Silverstone @ethanjdanger, Ciara Norris @ciaranorris18, Fran Penrose @franpenrose, Farzana Huysman @farzanahuysman, Olufolajimi Babasola @folajimi_, Andreas Orphanou, Ruth Augarde, Ben Ferris @benaferris ,  
23 Nov 2015 [21:35:16]ADJUST: -90ms/day - on advice from a Queens' student  
16 Nov 2015 [09:16:26]more Part IA Lego engineers! See Yee Tan, Yi Chao Ong, Chen Chun Chai (not clock builders!)  
09 Nov 2015 [09:43:05]Some observations on the effectiveness of the barometric compensator when it was removed for 5 weeks this year. July-Aug (compensator in place): <[link]> Sept-Oct (compensator absent): <[link]> Oct-Nov (compensator reinstated): <[link]>  
08 Nov 2015 [21:33:31]and winding by Emma Gee Olmedilla, Mariana Gee Olmedilla, Carmen Olmedilla Herrero and Andrew Gee  
08 Nov 2015 [21:09:23]Winding by IA lego engineers: Lizzi Hawkins, Elena Rastorgueva, Shrinikesh Arulselvan, Nimesh Patel, Seb Dickson,  
01 Nov 2015 [11:11:24]Winding by German and Danish Othello players: Matthias Berg, Erik Lund Jensen, Anita Raddatz, Ernst Raddatz and Imre Leader  
25 Oct 2015 [00:00:05]Clock Change for end of summer time, thanks to Alex Woolgar-Toms and Chris Nicklaus with Zoran Hadzhiivanov and Jim Minter  
19 Oct 2015 [12:33:20]ADJUST: +200ms/day to 39700 fine tuning after reinstalling barometric compensator. Also winding with Alex Woolgar-Toms who now has instructions for the clock change this weekend.  
15 Oct 2015 [14:23:05]ADJUST: -2300ms/day to 39500 after reinstalling the barocomp, and restarted the clocklogger after reconnecting GPS cable  
15 Oct 2015 [14:22:55]reinstalled the barometric compensator after a period without to see if it is working OK.  
14 Oct 2015 [22:33:40]accidentally pulled out the GPS cable - no data until next day  
14 Oct 2015 [22:33:27]TEA evening winding by CATHY ZHU,Jacky Yang, Guangzhi Sun, Andreas Kattamis, Federica Freddi, Vlad Tomescu, Marijana Vujadinovic, Arsalan Harris, Thomas Burridge, Gordon Hannah, Christopher Langridge, ajit ghosh,BradleyBull Daniel B Zoscha P Chris P, Isabel Vallina Garcia, Dusan Perovic, Dr Steven Whitehouse  
10 Oct 2015 [17:30:13]GCR 47.5s on the day of the Great Court Run. The ITV news report on the Great Court Run and the Clock is here [link] - rather nicely done  
06 Oct 2015 [11:00:30]top-up wind. Also installed a plumb bob to look for tower lean due to sunshine on south wall. Will have to wait for next summer.  
06 Oct 2015 [11:00:20]GCR 47.4 on top layer. Note that the Strikes do 20 strikes per revolution and 156 strikes per day - that is 7.8 turns per day. There are 19 turns on the top layer so the clock should be wound at least 2.4 days before the Run. Thursday at noon is a good time.  
06 Oct 2015 [11:00:10]The clock is 3s fast but I'm in the middle of an experiment to see how the clock runs without the barometric compenasator. Hence the correction by -3 seconds  
01 Oct 2015 [11:00:20]filming with Stuart Leithes - and a top-up wind  
28 Sep 2015 [20:02:56]winding with Peter Dawe - very interesting evening!  
24 Sep 2015 [08:31:37]winding by Fiona Holland @trincollcam - College Communications Officer - we have one at long last!  
20 Sep 2015 [16:40:00]Could this be a pigeon event? [link]  
17 Sep 2015 [14:12:21]wind with Nick Breeze and Luke Parsons. Nothing went wrong, so no litigation required. There is time, says Luke.  
14 Sep 2015 [15:00:00]wind while Paul Ashley takes photos - very nice ones indeed! [link] [link] [link] [link] [link] [link] [link] [link]  
11 Sep 2015 [08:15:23]Winding by College staff today! Jack Mortimer Francesca Baker-Pitman, Kirsty Ross, Karen Wells, Lee Froggatt, James Hobbs, Taylor Reynolds  
06 Sep 2015 [17:04:00]ADJUST: +1800ms/day to 41800 required after removal of barometric compensator  
05 Sep 2015 [14:17:40]ADJUST: +500ms/day to 40000 removed barometric compensator as an experiment to see how well the compensator has been working. In particular, I want to find out if the compensator also affects temperature compensation. For data this summer we seem to have dG/dp=-4ms/day per mbar and dG/dT= 46ms/day per deg [link] . This was worked out by finding the plane of best fit of the G(p,T) graph.  
03 Sep 2015 [21:38:53]top-up wind and in-depth discussion of physics with Dagmar Sternad, David Franklin, Daniel Wolpert and James Talbot from Peterhouse College...  
03 Sep 2015 [17:05:00]ADJUST: +300ms/day to 39500  
03 Sep 2015 [17:00:00]winding with Malcolm Crocker, Ruth Crocker and David Newland  
28 Aug 2015 [11:00:00]12th Cambridge Scouts winding with visitors from 12th Cambridge Scouts Ontario: Scouters:┬áColin, Hannah, Lisa, Catherine, Katie, Shelley. Scouts:┬áJonnie, Ben, Beba, Eleanor, Rebekah, Alex, William, Canadians: Sam, Sak, Bryce, Scott, Nathan, Joshua, Nicola, Tristan, Jacob, Connor, Brenden, A.J. followed by a punting trip and tea in Grantchester!  
25 Aug 2015 [19:35:17]The @bbcpm piece is around 5:43pm here [link] Quite fun! @BBCRadio4  
23 Aug 2015 [15:30:00]Julian Cooling (Adelweigian) thoroughly enjoyed the clock. He and Chris Nickolaus had a lengthy discussion on the subject of the Trinity and Hobson Conduits.  
16 Aug 2015 [20:06:30]winding by Ryan Wall, Kerrie Wall, Daniel Flack @drf39 @RWall1993  
10 Aug 2015 [20:00:00]Akemi Matsushima, Kengo Matsushima, Naoto Matsushima, Kanji Matsushima with Chris Nickolaus. Originally from Japan, visiting Cambridge on summer holidays from the US.  
07 Aug 2015 [17:22:51]winding with Dan Larsen  
31 Jul 2015 [08:00:00]winding thanks to Alex Woolgar-Toms  
23 Jul 2015 [21:34:36]Winders from the International Summer Schools: Kong Kit Tung, Lo Hoi Yi Joey, Shi Min Png, Ho Wing Tone Stephanie, William Strider, Isabella-Jane Shah @jbella_z , Cheng Tsz Ching Phoebe, Estefania Vega, Michelle Westlake, Tony Hoskins, Tang Chung Yan Sandy @yan_cy1, Kimba Wong, Carrock Sewell, Susan O Drake, Nanthaya Tisavipat, Rupert Gregg, Ernest Colvin  
19 Jul 2015 [10:00:00]Winding by Fairhavens after Selene Webb's memorial concert: Carl Ru 

Trinity College, Cambridge 2014