Worse for Wear is a clothing company  for women who ride motorcycles. The fascinating clothing they produce is very fashionable, comfortable, and needs to protect riders from impact and abrasion if they have an accident. Jackets and trousers have knee and hip pads  included to protect the rider when sliding many meters across asphalt. That’s why the fabric must be strong and abrasion resistant because if the fabric wears away too quickly, the rider’s skin will be exposed and injured.

To choose the perfect fabric, Scott and Laura, co-founders of the company, created an Impact Abrasion Resistance Testing Machine running on Arduino Uno to perform tests on different materials like knit fabrics, woven fabrics, and leather, to see how long it takes before the material is sanded completely through. I interviewed them to learn more about it!

– What is the impact abrasion resistance testing machine and how does it work?

When selecting fabric to use in our clothes, we have to make sure that it is strong and abrasion resistant. We use the impact abrasion resistance test machine to determine which fabrics will withstand abrasion (scraping and sliding) the best. It is important to us to test the fabrics ourselves and not rely solely on the claims of fabric manufacturers.

The machine has a weighted arm, like a hammer, suspended above an abrasive belt sander. A sample of the fabric that we want to test is wrapped around the head of the hammer and then dropped onto the moving sanding belt. An Arduino Uno is used to record the amount of time it takes to sand through the fabric sample.

Check the video below to see how it works:

– Why did you decide to use Arduino?

We have used Lilypad Arduino and Arduino Uno before to prototype some e-textile projects, so it was easy for us to get started on this one with our previous experience. The large number of accessory boards available made it simple to add an informational display and user interface to the machine. In just a few hours, we were able to very quickly create a machine to compare the abrasion resistance of a variety of fabric samples. The simplicity of working with Arduino was a very good choice for us, because our real business is creating clothing, not building test machines!

– What does Arduino control in the machine? 

An Arduino Uno is used to record the amount of time it takes to sand through the fabric sample. The method we use is based on European Union standards for motorcycle safety gear testing. To measure the fabric’s abrasion time, we use two thin copper wires (magnet wire). One wire is placed inside and another outside of the fabric sample before everything is wrapped around the head of the hammer. Each wire is then connected to ground on one end and an to input pin on the Arduino on the other end. The pins are in INPUT_PULLUP mode so a current runs through them. The LCD display on the Arduino tells us when both wires are connected properly.

Then, we start the belt sander and drop the hammer onto the spinning sanding belt. The outer wire breaks very quickly, breaking the connection to that pin [ digitalRead(outerWireIn) == HIGH ]. At this point, the Arduino records the start time. When the fabric wears through – usually within a couple of seconds – the inner wire is exposed to the sanding belt and quickly breaks. That marks the end time, which the Arduino records and displays on the LCD shield. A single type of fabric must be tested at least five times in order to make sure our recorded times are accurate.

Explore the details and download the code on Worse for Wear blog.