Lana Awad - Fab Academy

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Fab                 Academy 2          0          1          4 B a r c e l o n a
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10. Input Devices
Measure something: add a sensor to a microcontroller board that you've designed and read it

The assignment this week is to measure something by adding a sensor to a microcontroller. Instead of using the Attiny44, I made a Fabduino because it has the capacity to be used for my final project. Additionally, because of the flexure of the textile for the shoe, it's better to fabricate as breakout-style boards to move with the material. For my sensor, I chose to experiment with force sensitive resistors since that directly relates to what I want to achieve from the final project.

As for the breakout board for the force sensitive resistors, I began to understand the design first by reading the datasheet for the particular ones that I had. Force sensitive resistors are a polymer thick film component which exhibits decreasing resistance with increasing force (logarithmically). Force sensitive resistors require a pull-down resistor to ground. I want to design a breakout board for three FSR's, so I connected one leg to VCC in parallel, and the other leg connects to an analog pin using a 10K resistor as a reference to ground on each input line.

The boards were both milled successfully, and the components were soldered on. Unfortunately, the lab had run out of the AtMega168 that the design called for. I replaced it with the AtMega328, after being advised that the processors are interchangeable. However, when it came down to programming, an error came up within the Arduino IDE. A quick google search helped me understand that there are a few different versions of the AtMega328, such as 328P or 328AU. They're almost identical but carry different signatures. I found a tutorial on how to change the signature that the AVR expects, but another error appeared.

So I moved on and decided to mill the Barduino considering I had the AtMega328 on hand. Once the board was milled, the components were soldered on and then bootloaded within the Arduino IDE platform. For the board, I selected Arduino Pro (5V, 16MHz) w/ ATMega 328 and under tools, I selected the AVRISP MKII programmer. Everything programmed successfully! To make sure, I uploaded the blink sketch and it worked fine.

Finally, I wired the FSR breakout board to the Barduino. To test it, I used a simple analogRead() function in the code and then used the serial monitor to read the intensity of force.

Download the corresponding files here.

Back to index

10. Input Devices
Measure something: add a sensor to a microcontroller board that you've designed and read it

The assignment this week is to measure something by adding a sensor to a microcontroller. Instead of using the Attiny44, I made a Fabduino because it has the capacity to be used for my final project. Additionally, because of the flexure of the textile for the shoe, it's better to fabricate as breakout-style boards to move with the material. For my sensor, I chose to experiment with force sensitive resistors since that directly relates to what I want to achieve from the final project.

As for the breakout board for the force sensitive resistors, I began to understand the design first by reading the datasheet for the particular ones that I had. Force sensitive resistors are a polymer thick film component which exhibits decreasing resistance with increasing force (logarithmically). Force sensitive resistors require a pull-down resistor to ground. I want to design a breakout board for three FSR's, so I connected one leg to VCC in parallel, and the other leg connects to an analog pin using a 10K resistor as a reference to ground on each input line.

The boards were both milled successfully, and the components were soldered on. Unfortunately, the lab had run out of the AtMega168 that the design called for. I replaced it with the AtMega328, after being advised that the processors are interchangeable. However, when it came down to programming, an error came up within the Arduino IDE. A quick google search helped me understand that there are a few different versions of the AtMega328, such as 328P or 328AU. They're almost identical but carry different signatures. I found a tutorial on how to change the signature that the AVR expects, but another error appeared.

So I moved on and decided to mill the Barduino considering I had the AtMega328 on hand. Once the board was milled, the components were soldered on and then bootloaded within the Arduino IDE platform. For the board, I selected Arduino Pro (5V, 16MHz) w/ ATMega 328 and under tools, I selected the AVRISP MKII programmer. Everything programmed successfully! To make sure, I uploaded the blink sketch and it worked fine.

Finally, I wired the FSR breakout board to the Barduino. To test it, I used a simple analogRead() function in the code and then used the serial monitor to read the intensity of force.

Download the corresponding files here.