Get Started With the Bend Sensor
by cecilise in Circuits > Arduino
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Get Started With the Bend Sensor
We started by looking at how the Bend Sensor is buildt up, and how it works.
We then looked at different areas we can see it beeing used in.
Finally we made a lamp were you can change colour of the light, and also the brightness of a LED.
You will find the steps of how to make your own lamp, including code and fritzing wireing at the end.
Helpful Links With Facts About the Bend Sensor
Bend Sensor Build Up
The Bend Sensor consists of small conductive particles. When the sensor is straight (at rest) they are close together and provide 30 k ohms, nominal resistance value.
When bent, the conductive particles go further apart and the resistance value is incresed.
The more its bent the further apart the particles move, and the higher resistance it gives.
If bent the opposite direction, nothing happens to the particles. This means that the sensor only works in one direction. (The side with the stripes).
Basic Bend Sensor
Get started with the Bend Sensor
Set up in fritzing
Basic code Arduino
IN USE
It does not matter if you bend just the tip or if you bend the whole sensor, it is the angle of bend that count.
It works up to 90 degrees. If you bend it further you risk braking it.
(The sensor only works in one direction, if you want both ways, you can add an extra sensor at the back of an other.)
Tip: If you add steel wire to your sensor you can keep it in place as you bend it, to avoid it bouncing back.
Securing
The Bend Sensor has two small legs that can easily break. We recommend that you secure it by having something steady around the foot of it when you bend it, (fex lego).
If you use it in a product, try two have the foot secured and hidden inside the product.
If soldering wires, be sure to protect the legs from breaking.
If you break it, it is fixable with some conductive ink, be aware that the readings may not be as good.
Calibration
Each time you connect it to your computer you need two map it again.
We found that I does not matter if you have the same code, board etc, you still need to map it again.
The way you do this is to look in the serial monitor, check the value you get when straight, type this in to your mapping, then bend to max and type in that number. Then you can map those values to your preffered values.
Be aware that the next time you connect it, you may have to do this process again.
Bend Sensor and Piezo
Testing a bend sensor and a piezo.
Fritzing sketch and Arduino code.
A quick and basic set up.
Worked out okay, need to check that the mapping is according to your readings to get the best tone results.
IDEA: One of our thoughts was to make an instrument out of the bend sensor.
Another idea was to make a phone speaker, that is attached to your phone. As you bend it you can turn up or down the volume, or even shuffle songs randomly.
Bend Sensor and Servo
Connecting the Bend Sensor to a servo.
A good way to visualize the sensor output. Accurate readings.
IDEA: We were inspired by all the robotic hands out on the web. We made our own mechanical finger out of lego and some thread, using the code as provided here.
Bend Sensor Glove Links
Bend Sensor and RGB LED
Changing the colour of an RGB LED by using the bend sensor.
IDEA: Using the bend sensor and an RGB LED in a lamp, having the lampshade as the controller.
Bend Sensor and LCD
Connecting the bend sensor to a LCD screen.
Good for reading the sensor values on the screen.
IDEA: Our idea was to use this for a game that measures how strong you are. Putting the bend sensor onto something like a metal board, and giving each contestent the ability to show off how strong they are. While the LCD would write "superman!" to the winner or "chicken..." to the looser.
Bend Sensor and LED
Turning the LED off using the bend sensor.
IDEA: Using the bend sensor and a LED in a lamp, using the sensor as a switch.
Bend Sensor and LED
Using a Bend Sensor to fade a LED.
IDEA: Using the bend sensor and an LED in a lamp, having the lampshade as the controller to fade og brighten the LED.
Multiple Bend Sensors
The Bend sensors reads from 0-90 degrees. If you want 180 degrees, it is possible to have two bend sensors, back to back. We tried taping them together, using A0 and A1 on the Arduino UNO board.
You can combine multiple sensors to cover a larger area/ two axes.
The one not doing the reading will have some small output that might interfare, this could be solved by mapping the numbers out of your feedback.
With two sensors you will be able to read e.g. a finger movement with one joint.
IDEA: Using multiple bend sensors in e.g. a glove gives more accurate readings of the different joints.
Bend Sensor As Wearables
One of the advantages with the bend sensor is that its flexible. This makes it a good sensor to use in products related to the human body.
IDEA: Our idea was to use the sensor as part of a physiotherapy program. Where the sensor provides feedback on whether you have done your exersise correctly or not.
Links:
https://www.instructables.com/id/Squat-Sense/
Bend Sensor DIY
Flexie
To sum up our findings on the bend sensor, it seems like it is most adaptable to organic shapes because it is so flexible. At this stage in our prosess our sensors were a bit worn out (readings jumping all over the place), so we chose to work with light.
Light does not need the readings to be as accurate to show changes.
By following the pictures you can make your own Flexie lamp.
One bend sensor control the LED, adjusting brightness.
The other sensor controls the RGB, changing colors.
By bending the lamp shade you can control the light output from the lamp.