Product Prototyping

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For my final major project my idea is creating a crafted keyring pdeometer with an app functionality. In my spare time I like to create little toys using crochet, and I feel that it would be a challenge to see how this could be incorporated into a digital media artifact.

The soft toy part of the project will be based on the crochet style of amigurmi (Sinclair, 2006) where using the technique of crocheting in rounds, parts of a stuffed toy are made and then sewn together. This style of craft has become popular in recent years, and will hopefully increase the interest in my project. Key to making this style successful is simple yet “cute” and “attractive” character design. This could also be incorporated into the app, for example by showing a virtual version of the soft toy character.

-Adafruit’s Gemma microcontroller (Adafruit, 2015)

I am also quite interested in fitness, and was wondering how this could also be incorporated into my project. I thought of wearable technology and microcontrollers (such as Adafruit’s Gemma) and how this could be put into a small soft toy like the ones I make.


What I wanted to make was similar in size to this keyring I had so I decided to make some prototypes to test out the size of various components and how small I could make the product.




First I made a keyring of a similar size to the one above. I added some bells to the inside of it to see if it jangled well whilst I was walking. It seemed to perform fine, so a keyring pedometer might be able to work.


An Arduino Micro and an accelerometer next to a 2 pence piece.



A cardboard copy of the compenents.

I looked at using an Arduino Micro for my project as they are quite small. I figured out that I would also need to use an accelerometer to measure the position of the device which would then be used for counting steps. I also needed a battery to power the device as well as a way to send the data to a network, either via Bluetooth or through a Wifi shield.




I made a copy of the components to gauge the size of them when put together. I then made another crochet replica and tried to fit the components inside. I also added a flap to the keyring so that the battery could be easily replaced. This prototype did not go so well. The keyring was too big to be used comfortably. I could possibly change the structure of the demo toy as that might decrease a lot of the size, however the head itself (where all the components are stored) was still quite big so any size savings to be had might be quite marginal.



ATTiny (Atmel, 2015)

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I looked at some smaller microcontrollers such as the ATtiny which would be harder to develop for but would make the overall toy a lot smaller. I made a new cardboard circuit to make sure and compared it to the last one.

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Overall the toy was a lot smaller and more of a normal keyring size. For my project I will have to look carefully at what components I use to make sure the size of the micro controller is considered in the final design.

Sinclair, C., 2006. Craft: Transforming Traditional Crafts. Oreilly & Associates Inc.

Adafruit, 2015. Adafruit GEMMA v2 – Miniature wearable electronic platform ID: 1222 – $9.95 : Adafruit Industries, Unique & fun DIY electronics and kits. [online] Available from: [Accessed 28 Nov. 2015]., 2015. ATtiny85. [online] Available from: [Accessed 28 Nov. 2015].