Summary of DIY Flex sensor using Sugru and graphite powder (Resistencia flexible usando Sugru y polvo de grafito)
This article describes making a DIY flex (flexible) resistive sensor using Sugru mixed with graphite powder. It covers needed materials, step-by-step mixing until the putty conducts (target 10 kΩ–5 MΩ), embedding two wire terminals (one fully inside, one fully outside to avoid shorting), stretching the sensor, and letting it cure 24 hours. A test setup with an Arduino, a 1M/500k potentiometer, piezo buzzer, and breadboard is suggested for validating operation.
Parts used in the DIY flex sensor:
- Sugru package
- Graphite powder
- Piece of wire (about 5 cm / 2 inches)
- Multimeter
- Arduino or Arduino-compatible board (for testing)
- 1M or 500k potentiometer (for testing)
- Piezobuzzer (for testing)
- Breadboard
- Jumpers or single-core wires
Este es el primero de 5 instructables que surgieron del Instructables & Sugru build night (and day en nuestro caso) que hicimos en el Laboratorio de Juguete, el 20 de julio del 2013: una Resistencia Flexible o Flex Sensor hecha con Sugru y polvo de grafito:
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This is the first of 5 instructables from Instructables & Sugru Build Night (and day in our case) in Laboratorio de Juguete (toy laboratory) a makerspace from Buenos Aires, Argentina.
We built a DIY flex sensor using just Sugru and graphite powder.
Step 1: Materiales (materials)
Vas a necesitar:
*un sobrecito de Sugru
*Polvo de Grafito (se usa para lubricar cerraduras y se compra en cerrajerías o ferreterías)
*Un pedazo de cable pequeño (unos 5 cm.)
*ester o multímetro
Para hacer la prueba de funcionamiento del video vas a necesitar:
*Una placa arduino o arduino-compatible
*Un potenciómetro de 1M o 500k
*Un buzzer
*Protoboard y jumpers (o cables unifilares)
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You will need:
*A sugru package
*Graphite powder (it’s used to lubricate locks)
*A piece of wire (about 2 inches)
*Multimeter
To make the same test as in the video, you will need:
*An arduino or arduino-compatible board
*A 1M or 500k potentiometer
*A piezobuzzer
*Breadboard and jumpers
Step 2: Mixing
Comenzá a agregar lentamente el polvo de grafito. Tenés que mezclar y agregar y mezclar y agregar así que armate de paciencia! Cada tanto usá tu tester en modo resistencia para ver si empieza a conducir (y resistir). Si no conduce, no te desesperes y seguí agregando grafito…
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Start adding graphite slowly. You ‘ll have to mix and add and mix and add a lot so be patient. From time to time, grab your tester (in resistance mode) and check if it starts conducting (and resisting) If it doesn’t, don’t get anxious and keep on adding graphite…
Step 3: Wiring
Una vez que tu masilla resistiva esté conduciendo (medirá entre 10K y 5M, aproximadamente), estirala, tomá el cable (con sus extremos pelados) e introducilo dentro de la masa, de manera que uno de los extremos quede completamente dentro y el otro completamente fuera. Es muy importante que el extremo que quede fuera no esté en contacto con la masilla porque si no, será un atajo para los electrones. Finalmente, toma un pedazo muy pequeño de cable e introdúcelo en el extremo por el que se asoma el anterior. Estos dos extremos serán tus terminales. Listo! Ahora dejá descansar 24 horas tu sensor de flexibilidad.
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Once your resistive putty is conducting (between 10k to 5M of resistance), stretch it. Take your wired (stripped in both sides) and put it inside the putty. One of the sides must be completely inside the putty and the other must be completely outside. This is very important because if the copper from outside side is in contact with the putty, electrons will take this shortcut. Finally, take a very short piece of wire and put it next to the previous one. This will be your terminals. That’s all. Now let your flex sensor rest for 24 hours.
For more detail: DIY Flex sensor using Sugru and graphite powder (Resistencia flexible usando Sugru y polvo de grafito)
- What materials do I need to build the flex sensor?
You need a Sugru package, graphite powder, a short piece of wire, and a multimeter; for the video test you also need an Arduino, a 1M or 500k potentiometer, a piezobuzzer, a breadboard, and jumpers. - How do I know when to stop adding graphite to the Sugru?
Periodically check resistance with a multimeter; stop when the putty starts conducting and reads roughly between 10K and 5M ohms. - How should the wires be positioned inside the putty?
Insert a stripped wire so one end is fully inside the putty and the other fully outside, and add a very short piece of wire next to it to form the two terminals; ensure the outside copper does not touch the putty. - What resistance range should a working sensor have?
The article indicates a functioning resistive putty will measure approximately between 10K and 5M ohms. - Do I need to stretch the putty during assembly?
Yes; once the putty is conducting, stretch it before inserting the wires as described. - How long should the sensor rest before use?
Let the flex sensor rest and cure for 24 hours before use. - Can I test the sensor with an Arduino?
Yes; the article suggests using an Arduino or compatible board with a 1M or 500k potentiometer, piezobuzzer, breadboard, and jumpers to reproduce the video test.
