Do we have commercial IC's for Digital caliper - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: July 03, 2017, 07:10:12 am
content: Hi,I have break apart a Digital caliper, I think it's an ASIC that could measure the distance with capacitance slider or touch measurement, I wanted to build some specific tool for myself, I want to know if you happen to know if there are commercial parts available for this kind of job with a serial I2C, SPI, Uart or similar output?

author: tablatronix
author_rank: Regular Contributor
timestamp: July 03, 2017, 01:34:35 pm
content: Not sure how these work , but I am guessing it uses a relative linear encoding scheme, conductive? using quadrature encoding with index channel.dedicated chips exist for linear encoding, but it might use non standard phase angles.

author: tablatronix
author_rank: Regular Contributor
timestamp: July 03, 2017, 01:37:09 pm
content: Nope you are right capacative. hmmhttps://www.google.com/search?q=digital+caliper+teardown&num=50&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiS79bSne3UAhUBzIMKHT9hAd4Q_AUICygC&biw=1131&bih=1321#imgrc=oYvJRLfBtqhopM:

author: tablatronix
author_rank: Regular Contributor
timestamp: July 03, 2017, 01:50:15 pm
content: Those pins under the blue button appear to be data pins according to some hacks on google.

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: July 04, 2017, 05:12:10 am
content: Thanks for suggestions, I think it should have a similar principle to the mechanical version of rack and pinion, only this time by doing it with capacitive touch instead! I think we should have some Parts from different manufacturers,I just do not know what the IC manufacturer would call them or who have them.

author: albert22
author_rank: Regular Contributor
timestamp: July 04, 2017, 06:38:59 pm
content: Here you can find more info in how they work.http://www.grant-trebbin.com/2014/04/digital-calliper-teardown-and-repair.htmlIt seems that they all use a custom IC under a black blob. I would be surprised if a ready made IC existed for this application.More info can be found searching for the patent of the starret digital caliper (probably the first ever manufactured)

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: July 04, 2017, 11:11:05 pm
content: http://www.ichaus.de/productsEncoder ICs for various sensing technologies, interpolators etc.Most commercial application use optimized/integrated asics. I think Heidenhain sold a IC too.

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: July 05, 2017, 05:59:14 am
content: QuoteThanks,which part do you suggest?

author: kripton2035
author_rank: Super Contributor
timestamp: July 05, 2017, 06:12:45 am
content: this fellow made an open source arduino project to make what you search.should be raisonnable to compact this in a single small atmel avr.http://www.yuriystoys.com/2014/11/touchdro-version-2-now-available.htmlthe arduino :http://www.yuriystoys.com/2012/01/reading-gtizzly-igaging-scales-with.htmlhe also sells kits, and a bluetooth version of it.

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: July 05, 2017, 12:17:20 pm
content: Thanks for the info, I wonder if we have touch Quadrature encoder IC's, we have magnetic ones from AMS that's used for rotational encoding with magnets, with great precision and resolutionhttp://ams.com/eng/Products/Magnetic-Position-SensorsI think there most be some hidden capacitive encoder IC's too! for linear encoding