week 8

Final sensor!!!
Flexi sensor...

Figure 1 : This is flexi force.

What is flexi force??
 unique component that changes resistance when bent.

Figure 2: Flexi force can be bent.

 An un-flexed sensor has a nominal resistance of 10,000 ohms (10 K). As the flex sensor is bent in either direction the resistance gradually decreases. They convert the change in bend to electrical resistance - the more the bend, the more the resistance value.

 On MyDuino,have 2 length,those are "4.5" and "2.2" with different prices.

Figure 3: Flexi force "4.5" in length with RM65.00

Figure 4: Flexi force in length "2.2" with RM45.00

Application :
 gaming gloves, auto controls, fitness products, measuring devices, assistive technology, musical instruments, joysticks, and more.


 More information,visit this website: 
http://www.imagesco.com/sensors/flex-sensor.html 
https://www.sparkfun.com/products/8606? 
http://itp.nyu.edu/physcomp/sensors/Reports/Flex 
http://www.myduino.com/index.php?route=product/product&path=39&product_id=211 
http://www.myduino.com/index.php?route=product/product&path=39&product_id=180 

week 7

This week I buy flexiforce sensor at cytron.The famous buy online.

Figure 1: Post letter arrived

Figure 2: The flexiforce sensor is inside the box.

week 6

Due to the load cell sensor cannot use anymore,I change my sensor.The suitable sensor is Flexiforce sensor.

What is Flexiforce sensor?

Figure 1: Flexiforce sensor.

figure 2: structure of flexiforce sensor

Figure 3: small size of flexiforce

Figure 4: another size of flexiforce

References
 http://www.prweb.com/releases/zif-compatible/flexiforce/prweb4192224.htm

http://www.c-stamp.com/CS497000.htm

week 5

Activity : Testing circuit with load cell sensor

Component or equipment: load cell sensor,trainer,resistor 1kohm,multimeter

Result: By using wheatstone bridge circuit, the load cell not successfully produce the fix range. Beside that, the non- stability were result. The range is not stable.

Conclusion : The load cell sensor have 2 strain gauge.So that, when the force applied to the sensor, the range is not stabilize. Cannot produce fix rate. Moreover, the load cell sensor is not suitable to the mouth.

week 4

wheatstone bridge ??

Why I'm talking about 'Wheatstone bridge'?because this relate with my circuit and load cell sensor.

 Wheatstone Bridge is a device for measuring electrical resistance. When the bridge is connected in an electrical circuit, part of the current flows to the object whose resistance is unknown, and part flows to the resistor of known resistance. If more current flows through one side of the circuit than the other, the galvanometer shows the difference. The sliding contact is then moved along the wire until current flows equally along both sides of the bridge and the galvanometer shows zero.

 When the bridge is thus balanced, the unknown resistance is calculated by a formula. The formula is: X = RD'/D (X is the unknown resistance. R is the known resistance. D is the distance from the key to the right end of the meter stick. D' is the distance from the key to the left end.)

more information,visit these website
http://www.play-hookey.com/dc_theory/wheatstone_bridge.html
http://www.absorblearning.com/advancedphysics/demo/units/020202.html
http://www.citycollegiate.com/wheatstone_bridge.htm
http://www.cs.cmu.edu/~dst/E-Meter/wheatstone.html

Video about wheatsone bridge

week 3

Strain gauge has related with load cell sensor.The strain gauge has been in use for many years and fundamental for any other sensor such as pressure sensor and etc.

 When external forces are applied to a stationary object, stress and strain are the result. Stress is defined as the object's internal resisting forces, and strain is defined as the displacement and deformation that occur.

 Strain may be compressive or tensile and is typically measured by strain gages. It was Lord Kelvin who first reported in 1856 that metallic conductors subjected to mechanical strain exhibit a change in their electrical resistance. This phenomenon was first put to practical use in the 1930s.
Figure above is define as stress and strain.

Visit a few website to get knowledgeable about strain gauge.
http://www.sensorland.com/HowPage002.html 
http://www.omega.com/literature/transactions/volume3/strain.html 
http://www.dynasen.com/html/stressstraingages.html 

week 2

I'm still in research about my project. I have to change my previous sensor that is FSR sensor,to load cell sensor. FSR sensor having problem to get precision measurement. So, I try to test with this load cell sensor.I buy load cell sensor at Jalan Pasar,Kuala Lumpur with RM55.00.

Figure above is load cell sensor.Have 4 different colour of wires. This is web that content the datasheet and specification of load cell sensor,http://www.phidgets.com/products.php?product_id=3133_0