Open Hardware Summit 2024 was held in Montreal, Canada this year, and I had a blast attending the hands-on workshops.
This post is a workshop attendee documentation from the session – where we explored the electronics and design of a strain gauge based paddle – for the bedroom.
This paddle is designed to read the impact force via built-in PCB strain guage.
The kit came with the strain paddle PCB board, and a 3D printed battery holder, and an awesome “OSSM” (pronounce “awesome”) sticker.
Mechanically, when hitting is happening, the paddle will bend. When the paddle is bending, the strain gauge activates and converts the applied force, pressure, torque, etc. into an electrical signal that can be measured.
The developer here used the smallest traces available from JLCPCB, embedded the pattern, and turned it into a strain gauge.
Then the data acquisition circuit is something called “Wheatstone Bridge”
A Wheatstone Bridge is an electrical circuit used to measure an unknown electrical resistance by balancing two legs of a bridge circuit, one leg of which includes the unknown component. The primary benefit of the circuit is its ability to provide extremely accurate measurements.
From the below picture of the board, we can see that then the wheatstone bridge measurements get amplified, and then a ESP32 serves as professor + wifi that turns this paddle into an IoT device.
So since every paddle is unique and different, the resistors for the Wheatstone Bridge needs to be decided after measuring the resistance of the legs.
And the hands-on part of this workshop is to find the right resistor value to balance out the bridge, and to solder on the components.
I’m particularly interested and excited as this kind of technology becomes more “open” – digitizing embodied experience is so interesting, and totally fulfills the needs of those who are inner playful hardware-nerd archetype. With great spanking comes great responsibility.
These so-called “sex toys” are tools that are highly relevant to people’s wellness, as they help people discover personal sexuality preferences and to develop negotiation skills in interpersonal relationships.
I’m a huge proponent of positive sexual wellness education and responsible plays.
Thank you to the workshop facilitator KinkyMakers’ founders James Craig, Kyle Chisholm, Alex Warner for bringing these awesome inventions to the larger community, and doing it open hardware way 🧝🏻♀️
I can’t wait to decorate my paddle and start the classification of the data!