Subject: Re: C-Spring Sensor - 5/6 Second Period Hi Chris, Thanks for sending information on imnproving the C-Spring Sensor. Just a q= uick correction on the link to Robert's circuit for extending the period of= geophones. Leave out the "epics" part of your link. http://www.jclahr.com/science/psn/roberts/index.html Hi Kay, Thanks for the correction. I am struggling to use a new laptop running = Windows7, which seems to be unreliable and difficult to use. The roberts a= ddress just brings up the Epics section. I would still have to search for t= he article. How would you compare the C-Spring sensor to an AS-1 type vertical seismome= ter modified with either a "piano wire hinge" or a razer blade hinge clampe= d at both ends? =20 Piano wire and old style safety razor blades with the blades clamped an= d the two end loops flexing both make good flexures for an amateur vertical= seismometer. The problem that I see with the C spring arrangement is that = there are no mechanics to stabilise the lateral position of the mass. Depen= ding on the sensor design, you could get significant sensitivity to horizon= tal accelerations. This could be reduced by a lateral wire hinge at the top= end of the spring, or a V wire onto the mass.=20 I intend in the near future to update my notes on John's website. They = look pretty scrappy. I will send them through as I do them. Bob has also as= ked me to add a circuit of a period compensation amplifier, presumably to a= ttach to the input end of one of Larry's amplifiers. Would you have any int= erest? =20 Regards, Chris =20= Subject: Re: C-Spring Sensor - 5/6 Second Period
Hi Chris,Thanks for sending information on imnproving the C-= Spring Sensor. Just a quick correction on the link to Robert's circui= t for extending the period of geophones. Leave out the "epics" part o= f your link.Hi Kay,Thanks for the correction. I am struggling to use a= new laptop running Windows7, which seems to be unreliable and di= fficult to use. The roberts address just brings up the Epics section.= I would still have to search for the article.How would you compare the C-Spring sensor to an AS-= 1 type vertical seismometer modified with either a "piano wire hinge" or a = razer blade hinge clamped at both ends?Piano wire and old style safety = razor blades with the blades clamped and the two end loops flexing both mak= e good flexures for an amateur vertical seismometer. The problem that I see= with the C spring arrangement is that there are no mechanics to stabilise = the lateral position of the mass. Depending on the sensor design, you could= get significant sensitivity to horizontal accelerations. This could be red= uced by a lateral wire hinge at the top end of the spring, or a V wire= onto the mass.I intend in the near future to update my notes on J= ohn's website. They look pretty scrappy. I will send them through as I do t= hem. Bob has also asked me to add a circuit of a period compensation a= mplifier, presumably to attach to the input end of one of Larry's amplifier= s. Would you have any interest?Regards,Chris