Capacitance Sensor Guide (AD7746) - Hackaday

Home » Ad7746 Digikey » Capacitance Sensor Guide (AD7746) - Hackaday

Maybe your like

Skip to content

capacitive_sensor

[Marcus] has written up his experiences using the AD7746 capacitance sensor. He used the SparkFun breakout board in conjunction with an Arduino. The available Arduino code wasn’t that great so he rewrote it to be easier to understand. The AD7746 is an I2C device that can be continuously read, but this doesn’t mesh well with the Wiring libraries. Additionally, the calibration routine from the data sheet is difficult to understand. He’s included all of the code he used plus a Processing sketch to help visualize the input which will hopefully make your experience with the chip much more smooth.

Post navigation ← Visual Hardware Identification GuideCyclonic Dust Seperation →

20 thoughts on “Capacitance Sensor Guide (AD7746)”

  1. the cheaper way of doing is is transistor oscillator small capacitor and diode. or with little hacking single micro controller can handle this by it self

    Report comment Reply

    1. You won’t be able to achieve this level of precision and sensitivity with a mikrocontroler alone or jst a low amount of simple components, there is a good reason why such ICs exist. Look at the dataset for the specs about resolution and sensitivity of this IC.

      Report comment Reply

  2. i’ve used the ad7746 before, and I can tell you that you can’t get the kind of performance you see in the 7746 with a simple transistor oscillator or a little microcontroller. you can measure ridiculously small capacitances with this guy if you implement it properly.

    Report comment Reply

    1. can you give me the code and schematic

      Report comment Reply

      1. Hi Vipul!

        Do you get the code for AD7746 and Arduino?

        Report comment Reply

        1. Hi Raush… Can i get the code to configure AD7746 and read data from it? I am using arduino board

          Report comment Reply

  3. I think I just too cheep when it coming to parts, 90% of my parts coming from old VCR players and stereo

    Report comment Reply

  4. Yeah I’m not quite sure why anyone would use a $9 IC as just a touch sensor. There are many simpler and better options out there for button touch interfaces (or even scroll wheels, sliders, etc.). But I guess its a first step.

    For a basic touch only option, check out the Qtouch chips and AVR Qtouch library.

    Some cool things that the AD7746 could be used for: non-intrusive liquid level measurement, flow rate, various strain applications (pressure, weight), humidity sensing, etc.

    Report comment Reply

  5. I made a capacitive sensor matrix 4×3 with little more than atmega8 and some caps. The performance you get with a micro is enough. These sensors are probably designed for something more sophisticated.

    Report comment Reply

  6. is there a life beyond arduino, adafruit industries and sparkfun?

    Report comment Reply

  7. @lekernel

    Yep. It’s called Digikey. A lot cheaper too, but perhaps too scary for most people.

    Report comment Reply

  8. @lekernel

    yeah, i’m getting tired of the arduinoaday.com too.

    Report comment Reply

  9. You cant use this near rf sources, it goes crazy.

    Report comment Reply

  10. Have a look at AD7147 and AD7150:

    Cheaper ($3-$4), and AD7147 supports several input channels.Unfortunately they come in really tiny packages. Hard to make your own breakout board with these tiny leads.

    Ironically, AD7746 is available as MSOP. You can solder it to a normal prototyping stripboard if you cut the stripes on the board in half.

    Report comment Reply

  11. I used touchpads from scrapped laptops for touch sensors before with an avr… works great, much cheaper.

    http://forums.bit-tech.net/showthread.php?t=112110

    Report comment Reply

  12. sure, and more interesting than arduino self-proclaimed “hacks”, but hey, it’s not what the masses like.

    Report comment Reply

  13. My gawd! $24.95 to sense touch? OUCH!!!

    Whatever happened to the cheap $0.05 solution of using a resistor and capacitor pair tied to a port pin along with some simple code for sensing finger proximity? (OK… more like $1.50 at your neighborhood Sh!tShack store with their 3000% mark-up of repackaged surplus.)

    Even a hard to find, overpriced, $3-$6 QT113G chip still needs a capacitor wired to it?

    #2 (old school)engineering rule: K.I.S.S – Keep It Simple Stupid

    Report comment Reply

  14. @ dan: Digi-key cheap? I suppose it’s all relative, as with everything else. (I still loves me my Digi-key however).

    Report comment Reply

  15. Where can i get the code?

    Report comment Reply

  16. Hello, I am using arduino and AD7746 to measure tiny capacitance values, can you please share your code with me?

    Report comment Reply

Leave a ReplyCancel reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Search Search for: Never miss a hack Follow on facebook Follow on twitter Follow on youtube Follow on rss Contact us Subscribe If you missed it

  • Clone Wars: IBM Edition

    16 Comments

  • A Linux Power User Puts SteamOS To Work

    39 Comments

  • NPAPI And The Hot-Pluggable World Wide Web

    16 Comments

  • The Time Clock Has Stood The Test Of Time

    32 Comments

  • The Rise And Fall Of The In-Car Fax Machines

    53 Comments
More from this category Our Columns

  • Genetic Therapy Aims To Bring Hearing To Those Born Deaf

    No comments

  • Ask Hackaday: Do You Curb Shop Components?

    59 Comments

  • Keebin’ With Kristina: The One With The Cheap-O Keyboard

    1 Comment

  • For The Fun Of It

    12 Comments

  • Fighting Food Poisoning With A Patch

    30 Comments
More from this category Search Search for: Never miss a hack Follow on facebook Follow on twitter Follow on youtube Follow on rss Contact us Subscribe If you missed it

  • Clone Wars: IBM Edition

    16 Comments

  • A Linux Power User Puts SteamOS To Work

    39 Comments

  • NPAPI And The Hot-Pluggable World Wide Web

    16 Comments

  • The Time Clock Has Stood The Test Of Time

    32 Comments

  • The Rise And Fall Of The In-Car Fax Machines

    53 Comments
More from this category CategoriesCategories Select Category 3d Printer hacks Android Hacks Arduino Hacks ARM Art Artificial Intelligence Ask Hackaday ATtiny Hacks Battery Hacks Beer Hacks Biography blackberry hacks Business car hacks Cellphone Hacks chemistry hacks classic hacks clock hacks cnc hacks computer hacks cons contests cooking hacks Crowd Funding Curated Current Events Cyberdecks digital audio hacks digital cameras hacks downloads hacks drone hacks Engine Hacks Engineering Fail of the Week Featured Fiction firefox hacks FPGA g1 hacks Games google hacks gps hacks green hacks Hackaday Columns Hackaday links Hackaday Store Hackerspaces HackIt handhelds hacks hardware High Voltage History Holiday Hacks home entertainment hacks home hacks how-to Interest internet hacks Interviews iphone hacks ipod hacks Kindle hacks Kinect hacks laptops hacks Laser Hacks LED Hacks Lifehacks Linux Hacks lockpicking hacks Mac Hacks Machine Learning Major Tom Medical Hacks Microcontrollers Misc Hacks Multitouch Hacks Musical Hacks Netbook Hacks Network Hacks News Nintendo DS Hacks Nintendo Game Boy Hacks Nintendo Hacks Nintendo Wii Hacks Nook Hacks Original Art Palm Pre Hacks Parts PCB Hacks Peripherals Hacks Phone Hacks Playstation Hacks Podcasts Portable Audio Hacks Portable Video Hacks PSP Hacks Radio Hacks Rants Raspberry Pi Repair Hacks Retrocomputing Retrotechtacular Reverse Engineering Reviews Robots Hacks Roundup Science Security Hacks Skills Slider Software Development Software Hacks Solar Hacks Space Tablet Hacks Teardown Tech Hacks The Hackaday Prize Tool Hacks Toy Hacks Transportation Hacks Uncategorized Video Hacks Virtual Reality Weapons Hacks Wearable Hacks Weekly Roundup Wireless Hacks Xbox Hacks Our Columns

  • Genetic Therapy Aims To Bring Hearing To Those Born Deaf

    No comments

  • Ask Hackaday: Do You Curb Shop Components?

    59 Comments

  • Keebin’ With Kristina: The One With The Cheap-O Keyboard

    1 Comment

  • For The Fun Of It

    12 Comments

  • Fighting Food Poisoning With A Patch

    30 Comments
More from this category Recent comments
  • Dan on Clone Wars: IBM Edition
  • sweethack on Pushing China’s EAST Tokamak Past The Greenwald Density Limit
  • David H on Clone Wars: IBM Edition
  • SteveS on Clone Wars: IBM Edition
  • Sergey on Clone Wars: IBM Edition
  • arifyn on ESP32-P4 Powers Retro Handheld After A Transplant
  • Bill on Clone Wars: IBM Edition
  • David H on When Electricity Doesn’t Take The Shortest Path
  • David H on Atari Brings The Computer Age Home
  • David H on Atari Brings The Computer Age Home
Loading Comments... Write a Comment... Email (Required) Name (Required) Website