Close
0%
0%

Design Ideas

Simple designs ideas that might prove useful

Similar projects worth following
I've been designing (and inventing) for more than forty years and from time to time I come up with good ideas that might be of benefit to others...

I'm not talking about earth shattering designs but simple designs to make life easier... Here's an example, just add a resistor and a LED to a fuse... it will light when the fuse is blown... now put it in any device and the chances are you will find the blown fuse in seconds... it's ideal for cars where fuses tend to blow when it dark ;) In an ideal world this feature would be integrated into all fuse holders.... different LED colours might indicate the fuse rating...

Over time I will add many more but to start off I will add the latest idea that prompted this project...

Aim:

Making a cheap piezo disk work as sensor.

Need:

When it came to building the sensors for another project (https://hackaday.io/project/3336-wifi-sensors) I could not find any that made sense financially... The entire sensor device including the housing was costing less than $10 but the sensor was costing $20 to $30 or more.

Prior Knowledge:

First it must be understood that vibration sensor detect movements as a result of a force applied, They do this by restricting the movement of one side of the sensor and allow the other to move freely... It's the movement of one side in relation to the other that produces the output signal...

Reasoning:

In previous designs I experimented with inexpensive piezo disk but as these are primarily designed as output devices their use as sensors (vibration/movement) is somewhat lacking. The problem as identified above is that both plates of the piezo disk are effectively fixed and one can't really move in respect to the other...

A piezo disk would certainly detect vibrations from a window breaking but almost certainly not the small vibration resulting from opening a window or cutting glass.

Solution:

If we attach a small weight to one of the plates by means of a rigid wire, any vibration experienced by the "sensor enclosure" will be transmitted to the sensor causing it to vibrate. Within a very short period all vibrations will dampen leaving the weight (which is not dampened to the same degree) to continue to vibrate causing the plate to vibrate and generate an electrical signal...

(Mechanical amplification or vibration)...

Not sure if I explained it well but it might be worth pursuing especially if you require many sensors and don't want to fork out hundreds.

  • Making the sensor...

    Michael O'Toole05/03/2016 at 00:58 0 comments

    For the weight at the end I used various beads from the local hobby shop, for the attaching wire I used leads from a various components (a leg from a IN4148 diode worked quite well)...

    By varying the bead weight and the length (and diameter) of the attaching wire, you can actually tune the sensor to some degree...

    The sensors were attached to door and window frames and resulted in substantial improvement to detecting any attempt to gently pry open the door or window...

View project log

Enjoy this project?

Share

Discussions

Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates