## Force Sensitive Resistors are for squeezing! Massive tutorial AND they’re in stock!

What is a Force Sensitive Resistor?
FSR’s (Force Sensitive Resistors) are basically a resistor that changes its resistive value (in ohms Ω) depending on how much its pressed. These sensors are fairly low cost, and easy to use but they’re rarely accurate. They also vary some from sensor to sensor perhaps 10%. So basically when you use FSR’s you should only expect to get ranges of response. While FSRs can detect weight, they’re a bad choice for detecting exactly how many pounds of weight are on them…

Some basic stats
These stats are specifically for the Interlink 402, but nearly all FSRs will be similar. Checking the datasheet will always illuminate any differences

• Size: 1/2″ (12.5mm) diameter active area by 0.02″ thick
• Price \$7.00 from the Adafruit shop
• Resistance range: Infinite/open circuit (no pressure), 100KΩ (light pressure) to 200Ω (max. pressure)
• Force range: 0 to 20 lb. (0 to 100 Newtons) applied evenly over the 0.125 sq in surface area
• Power supply: Any! Uses less than 1mA of current (depends on any pullup/down resistors used and supply voltage)
• Datasheet (note there are some mathematical inconsistancies in here)

How to measure force/pressure with an FSR
As we’ve said, the FSR’s resistance changes as more pressure is applied. When there is no pressure, the sensor looks like an infinite resistor (open circuit), as the pressure increases, the resistance goes down. This graph indicates approximately the resistance of the sensor at different force measurements. (Note that force is not measured in grams and what they really mean is Newtons / 100!)

We put together a MASSIVE tutorial on what they are, how to use them and example code for use with Arduino. You can view the tutorial here “FSR Force Sensitive Resistors are for squeezing!”.

…and pick’em up at the Adafruit store – Force-Sensitive Resistor (FSR).

Filed under: announce,arduino — by adafruit, posted May 20, 2009 at 1:55 pm

## CE smart grid using Tweet-a-watt

This is interesting…

The CE Smart Grid in Jackson Michigan is home of Consumers Energy’s Smart Grid and Meter Test Farm. This site will receive responses from the meter groups updating their status real time.

They’re using the Tweet-a-watt!

Filed under: tweet-a-watt — by adafruit, posted at 11:06 am

## Piezo with an Arduino & photoresistor

Short video (m4v) of a piezo, photoresistor and Arduino….

Here’s the breadboard view to wire this up yourself…

And.. here’s the code we used from TodBot!

```

int photosensorPin = 0;
int piezoPin = 9;

int val = 0;

void setup() {
pinMode(piezoPin, OUTPUT);
}

void loop() {
digitalWrite(piezoPin, LOW);
val = val/2;

for( int i=0; i<500; i++ ) {  // play it for 50 cycles
digitalWrite(piezoPin, HIGH);
delayMicroseconds(val);
digitalWrite(piezoPin, LOW);
delayMicroseconds(val);
}
}

```

## Hubble tools…

The tools that will be used to service NASA’s Hubble Space Telescope on the STS-125 mission are displayed in the NASA News Center at NASA’s Kennedy Space Center in Florida. At far right is the pistol grip tool. It can install and remove instruments, drive latches and open doors. A self-contained, high-torque drive, the tool features an on-board computer that permits users to tailor its performance to the mission demands. In the foreground are the card extraction and insertion tools to enable removal of electronic cards. At top center is the plastic version of the pistol grip tool used by astronauts during practice in the water tank at NASA’s Johnson Space Center. At center left is the bit caddy.

Filed under: random,tools — by adafruit, posted at 11:35 am

## Ghostmatrix – Glow-in-the dark printer using miniPOV….

Rmutt’s LED glow-in-the-dark printer using an Adafruit miniPOV… via EMSL.

Filed under: minipov — by adafruit, posted at 10:27 am

## MakerBot sings the imperial march and makes a Darth Vader Head

This video is a lot of fun, the ending is the best…

## Blimpduino assembly line up and running…

You can’t beat child labor! 200 Blimpduino kits being readied for Maker Faire. (And yes, as you can see out the window our house is a construction site at the moment. We’re building a drone lab, among other expansions.)

## Laser cut caliper tool

Filed under: lasers — by adafruit, posted at 12:22 pm

## New in the store! 3-axis accelerometer (±3g analog output)

One more for this lovely Saturday night! Say hi to this Triple-axis accelerometer with 3 analog outputs for X, Y and Z axis measurements on a 0.75″x0.75″ breakout board. The ADXL335 is the latest and greatest from Analog Devices. Runs from 1.8-3.6 volts (3.3 is suggested), with radiometric output. That means that 0g measurement output is always at half of the supply voltage Vdd, -3g is at 0v and 3g is at Vdd with full scaling in between. Fully assembled and tested. Comes with 6 pin 0.1″ standard header in case you want to use it with a breadboard or perfboard. 4 x 0.125″ mounting holes for easy attachment. See the ADXL335 webpage for datasheets and pick one up at the Adafruit store

Filed under: announce — by adafruit, posted May 16, 2009 at 10:24 pm

## New in the store – IR distance sensor w/cable (10cm-80cm)

This SHARP distance sensor bounces IR off objects to determine how far away they are. It returns an analog voltage that can be used to determine how close the nearest object is. Comes with 12″ long 3-JST interface wire. These sensors are good for short-range detection. For over 1 m distance, we suggest using sonar sensors

To use, connect black wire to ground, red wire to 5V and white wire to analog input. The analog voltage out will range from 3V when an object is only 4″ (10 cm) away and 0.4V when the object is 32″ (80 cm) away

Here’s a quick and simple project you can do with an Arduino, a breadboard, 2 servos and the IR distance sensor – a edge detecting robot!

``````
#include "Servo.h"

Servo leftServo;
Servo rightServo;
int distSensor = 0;

void setup() {
leftServo.attach(10);
rightServo.attach(9);
}

void loop() {
if (distSensor < 500) {
leftServo.write(180);
rightServo.write(0);
delay(400);
leftServo.write(180);
rightServo.write(90);
delay(900);
}
else {
leftServo.write(0);
rightServo.write(180);
}
}

```
```
Filed under: announce — by adafruit, posted at 7:47 pm

## High-power TV-B-Gone

High powered TV-B-Gone in a pack of smokes…

Filed under: tvbgone — by adafruit, posted at 4:05 pm

## DigiKey price sorting script

If you’ve been using Mouser to buy parts lately, you may have noticed that with their recent site re-design they also added price sorting which is just fantastic. Unfortunatly, DigiKey hasn’t caught up but friendly poster morganl brought my attention to a GreaseMonkey script written by Sajid Sadi that adds a sorting ability while browsing. I tried it out and it works great!

Filed under: Uncategorized — by ladyada, posted May 15, 2009 at 6:21 pm

## Motorized moutainboard

Here’s a skateboard that doesn’t need a hill (or a push-off from your foot) for propulsion. James Howland and his project buddies, Pat Rimel and Nate Davis, created a motorized mountainboard as a project for their mechanical engineering class at Colorado State University. The gadget has a handheld speed control, and the team was able to get the board up to speed of 13 miles per hour. The speed decreases while traveling up hills but still has enough torque to conquer hills with ease. The mountainboard also has buzzer on the nose that acts as a horn.

Filed under: projects — by adafruit, posted at 2:07 pm

## Testing a MiniPOV with a bike wheel powered by a motor…

Filed under: minipov — by adafruit, posted May 14, 2009 at 11:58 pm

## Circuit board artwork

Circuit board artwork created with the T-Tech QuickCircuit 5000 PCB prototyping machine. This was an exercise to get familiar with the newest addition to my lab, so I used artwork from some of my friends and routed them into copper. They look pretty cool and show off some of the precision of the machine.

The monkey picture is from Phil…

Filed under: art — by adafruit, posted May 13, 2009 at 11:51 pm

www.flickr.com