The 1121 provides an interface to non-Phidgets resistance sensors such as: Force-Sensing Resistors (FSR), light sensors, thermistors (heat sensors), and bend sensors.
The Voltage Divider eliminates the need to connect a resistor to an analog input by putting a high precision potentiometer on the board to allow the adjustment of the 'fixed' resistor.
The interface to the variable resistance sensor is a convenient terminal block.
|Controlled By||VoltageRatio Input|
|Sensor Output Type||Ratiometric|
|Resistance Min||1 kΩ|
|Resistance Max||21 kΩ|
|Optimal Measurement Resistance Min (@ 1kΩ)||100 Ω|
|Optimal Measurement Resistance Max (@ 1kΩ)||10 kΩ|
|Optimal Measurement Resistance Min (@ 21kΩ)||2 kΩ|
|Optimal Measurement Resistance Max (@ 21kΩ)||200 kΩ|
|Current Consumption Max||5 mA|
|Supply Voltage Min||3 V DC|
|Supply Voltage Max||5.3 V DC|
|Recommended Wire Size||12 - 24 AWG|
|Operating Temperature Min||-40 °C|
|Operating Temperature Max||105 °C|
|Date||Board Revision||Device Version||Comment|
|August 2007||0||N/A||Product Release|
Welcome to the 1121 user guide! In order to get started, make sure you have the following hardware on hand:
Next, you will need to connect the pieces:
Now that you have everything together, let's start using the 1121!
In order to demonstrate the functionality of the 1121, we will connect it to the 1018, and then run an example using the Phidget Control Panel on a Windows machine.
The Phidget Control Panel is available for use on both macOS and Windows machines. If you would like to follow along, first take a look at the getting started guide for your operating system:
Linux users can follow the getting started with Linux guide and continue reading here for more information about the 1121.
After plugging in the 1121 into the 1018, and the 1018 into your computer, open the Phidget Control Panel. You will see something like this:
The Phidget Control Panel will list all connected Phidgets and associated objects, as well as the following information:
The Phidget Control Panel can also be used to test your device. Double-clicking on an object will open an example.
Double-click on a Voltage Ratio Input object in order to run the example:
General information about the selected object will be displayed at the top of the window. You can also experiment with the following functionality:
Why is adjusting the resistance important? The Voltage Input can measure a voltage between 0V and 5V. When using variable resistance devices a voltage divider is commonly used to measure the changing resistance. The two resistors in the divider form a voltage, based on the ratio between them. This voltage is then measured by the Voltage Input. To optimize the voltage divider to meet your needs, you have to adjust the fixed resistance to match the characteristics of your chosen sensor. To adjust the resistance on the 1121, simply turn the screw on the potentiometer clockwise to decrease the resistance and counterclockwise to increase it. You'll see a change in resistance of about 900Ω to 1000Ω per revolution. First, adjust the resistance for no stimuli on your sensor and then apply the maximum possible stimuli and make sure that sensor's voltage stays within a range that gives you acceptable resolution. At the extremes (less than 0.25V or greater than 4.75V), a very large change in stimuli (and therefore change in the resistance) produces only a small change in voltage. Keep adjusting until you get a range you are happy with.
|Force Sensor||Digikey||force sensor||IESP-12|
|Force Sensor||Trossen Robotics||Force Sensing FSRs||n/a|
|Thermistor||Digikey||Thermistor Radial||Choose a thermistor with a resistance in the range 10K ohms.|
The Phidget Cable is a 3-pin, 0.100 inch pitch locking connector. Pictured here is a plug with the connections labelled. The connectors are commonly available - refer to the Analog Input Primer for manufacturer part numbers.
This adapter can be used to interface one Interlink FSR. Here's a complete list of all the different varieties we sell:
|Product||Sensor Properties||Physical Properties|
|Image||Part Number||Price||Force Min||Force Max||Sensing Area|
|3103_0||$6.50||1 N||20 N||19.6 mm²|
|3104_0||$7.50||1 N||20 N||126.7 mm²|
|3105_0||$10.00||1 N||20 N||14.5 cm²|
This adapter can be read by any Phidget with an Analog Input or VINT Hub port. It will connect to either one using the included Phidget cable. VINT Hub ports can behave just like Analog Inputs, but have the added flexibility of being able to be used as digital inputs, digital outputs, or ports to communicate with VINT devices. For more information about VINT, see the VINT Primer.
|Image||Part Number||Price||Number of Voltage Inputs||Voltage Input Resolution|
|HUB0000_0||$30.00||6 (Shared)||* 16 bit|
|SBC3003_0||$120.00||6 (Shared)||* 16 bit|
This adapter comes with its own Phidget cable to connect it to an InterfaceKit or Hub, but if you need extras we have a full list down below. You can solder multiple cables together in order to make even longer Phidget cables, but you should be aware of the effects of having long wires in your system.