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Low cost Accelorometer/Shock Sensor?

Hi all,

Im looking for a low cost accelorometer or a peizo shock sensor specifically in the form of an IC that can be easily integrated into any a printed board without additional signal conditionaing circuits. There are some variants availble from Analog Devices and Freescale but are extremely costly (Rs 267 an IC, I need 4 of them) to serve my purpose.

The idea is to sense a finger tap. The sensors will be attached to each finger of a glove to be worn by a person. when the user taps the finger on any surface, it needs to be picked up. I do not require precise shock measurements. I just need to sense wher or not the shock has exceeded a certain threshold value.

Is there any PCB manufacturing facility like PCBexpress.com, where I can upload gerber files in INDIA.

CEans, I'm looking forward to your suggestions and innovative ideas.

Replies

  • debu
    debu
    @silenthorde: The cheapest 3-axis accelerometer that I have ever seen costs Rs. 850 (Freescale MMA7260Q), you will only need one of them to get the XYZ position, and there is no need for any external components, this will interface with the ADC of your controller.

    For pressure sensing, you could use cheap piezo peices available in the market ~Rs. 30/sq in (I've used these in the past to make cheap floor sensors). You will need to make an OpAmp based signal conditioner with that. Alternatively you could use an FSR like FlexiForce, these will cost you roughly Rs.400-500 (on import) and will be far more reliable then the piezoelectric variety.

    As for PCB fabrication, there are more then a 1000 vendors here in Delhi who fabricate PCBs and its very economical (roughly ~Rs. 3/sq in for around 50 pieces).

    Hope this helps.

    Regards,

    Debu 😀
  • silenthorde
    silenthorde
    Thanks a lot Debu

    #-Link-Snipped-#

    Check out this link. Even a Rs 267 accelorometer is a bit costly for me. Im looking for cheaper solutions. I guess these are MEMs which make it costly. Any alternative design within Rs 100-150.
  • silenthorde
    silenthorde
    Are there local manufacturers producing accelerometer ICs? Anyone?
  • Muffy
    Muffy
    Hi, a 3 axis accelerometer for your application seems to be a bit of an overkill. But if this is a one time project or a prototype , you could request samples form Freescale, they are quite generous.

    Alternately ,maybe, you could use a touch sensor at the tip of of glove, with a small separation between the finger and the sensor. A mild tap causes a smaller area of skin to be in contact with the sensor , and a harder tap more area in contact, the circuit could be calibrated to read the changes in the parameters of the skin (resistance/capacitance) and thus the threshold could be set? 😒

    #-Link-Snipped-#

    The QT100 IC seems interesting.


    😀
    Good luck.
  • silenthorde
    silenthorde
    That was really helpful Muffy, nice info.

    Thanx a ton

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