Measuring stretch forces isn’t easy – unless you have some conductive rubber cord! This cord is 2mm diameter, and 1 meter long, made of carbon-black impregnated rubber. Usually this material is used for EMF gasketing, but its also very fun to play with.
In a ‘relaxed’ state, the resistance is about 350 ohms per inch. As you pull on it, the resistance increases (the particles get further apart). As you stretch it out, the resistance increases. So lets say you have a 6″ piece – thats about 2.1 Kohms. Stretch it to 10″ long and now it is 10″/6″*2.1K = 3.5 Kohms. You can stretch the rubber about 50-70% longer than the resting length, so a 6″ piece shouldn’t be stretched more than 10″. Once the force is released, the rubber will shrink back, although its not very ‘fast’ and it takes a minute or two to revert to its original length. It’s not a true linear sensor, and the resistance may vary from batch to batch, so we consider it a way to measure stretching motion but isn’t really precise.
This stuff is fun, so we give you a full meter and also two alligator clips (to connect to the cord) and a 10K resistor. Together, you can use these to make a simple voltage divider. Then use this handy Thermistor tutorial to measure the analog voltage and convert that back to resistance.
Technical Details
Length: approximately 1 meter = 39 inches
Diameter: 2mm
Resistance: 350-400 ohms per inch / 140 – 160 ohms per centimeter
Fast Shipping and Professional Packing
We offer a broad range of shipping options due to our long-standing partnerships with UPS, FedEx and DHL. Our warehouse staff is highly trained and will pack the goods according to our precise and exact specifications. Before shipping, all goods will be thoroughly examined and securely secured. We deliver to hundreds of thousands of customers every day in different countries. The fact that we are determined to become the largest online retailer in the world is evident. Warehouses and distribution centres can be located in Europe as well as the USA.
Note: Orders with more than one item will be assigned a separate processing time for each item.
Before shipment, all ordered items will be thoroughly examined. Most orders are now shipped within 48 hrs. Delivery is expected to take between 3 and seven days.
Returns
Stock is dynamic, and cannot be fully controlled by us because of the involvement of multiple parties including the factory and our warehouse. This means that the actual stock could alter at any time. It's possible that the stocks could be depleted after your order has been processed.
The policy is for 30 days. Unfortunately, if 30 days have passed from the date you purchased the item, we will not be able to provide a refund or exchange.
The item must not be in use and must be in the original packaging. You must have the item in the original packaging.
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