10/02/2015 at 05:15 •
Enabled development is planning on running Summer School Workshops (Australian summer is January, 2016) to keep high school students busy during there breaks, they want Nuvotion to run a one day workshop centered on applied programming of the Tea Dunker STEM. This raised many question that the team had to answer regarding deploying the product in particular hardware and software licenses.
A lot of discussion was had between team members of legal ownership and contribution to the project. We came to the conclusion that the Tea Dunker product is not really the value proposition more a method of education.
The real value comes from how the education component (STEM Tea Dunker Workshop) is to be delivered as this relies heavily on Nuvotions intellectual property.
The design team in consultation with partners has decided to release the software/firmware code under GPL/V3 license and hardware files under Open Source Hardware (OSHW) Definition 1.0 .
08/16/2015 at 12:46 •
Going from computer aided design to production would not of been possible without the use of extensive prototyping, 3D Printing was used to evaluate design of the base prior to going through with tooling up CNC routing or plastic injection molding machines for final production. A CNC laser cutter was used to rapidly prototype the upper support structure, having access to such tools meant that many iterations of of designs could be evaluated in a very short time frame.
Electronics prototyping started off on breadboard then quickly, evolved into a home made circuit board utilising the well documented art of photo transfer and chemical etching. As the quality was not representative of the final form, PCB prototypes were subsequently outsourced to a specialist company ITEAD Studio this resulted in high quality circuit boards within the space of a week from time of order at a very reasonable cost.
Prototype Tea Dunkers
Evaluation, Prototyping to Production:
The Tea Dunker Machine is currently in the final phase of prototyping. We have functional models and are looking forward to user group testing (primary and secondary school students). The plan in the coming weeks is to observe a test group of students as thy interact with the product and seek their feedback on fit, feel and function. Our plan is to expose the students to the model and observe how they assembly it. The second stage will be how do we interact with them to program it!
Moving forward we will be looking at a small production run, we have selected a quantity of 300 units as it is a trade off between getting the unit price down and being able to wear the cost of production with our limited budget.
08/16/2015 at 11:44 •
Most people think of programmers geeks bashing away at a keyboard, with arcane symbols spewing across the screen, an energy drink on the side, with the protagonist sporting a ponytail.
The reality is a little different, as good programmers will spend the majority of their time planning their code and thinking about information flows, rather than actually writing code. Also, energy drinks taste really bad.
Coding without a flowchart can be a frustrating process of variables floating around in your head, trying to step through logical sequences in your head, as well as worrying about language syntax.
A flowchart will not write the code for you, but it is a rather excellent way of preparing yourself for the logical sequences before you hit the inevitable silly syntax semantics.
This is the first flowchart for the Tea Dunker. The unit's operation has changed a little bit since then and I'm in the process of updating it for the latest iteration.
08/14/2015 at 05:20 •
With the mechanics now sorted it was time to consider the electronics, but before laying out a schematic a flow chart of operation had to developed.
The initial flow and sequence of events are as follows:
- Swing Arm starts in the up position
- User places tea cup full of boiling water under the swing arm additionally use wraps tea bag string around swing arm.
- User depressed Set Button, swing arm moves to the down position dunking the tea bag in the boiling water
- Tea bag remains in the boiling water until the desired time has elapsed (default 3mins), Swing arm moves to the up position
- At any time the reset button can be activated to move the Swing Arm up and tea bag out of the boiling water.
The flow chart helped identified the requirements for the electronics, added features where deemed necessary to meet the needs of the end users, eg vision impaired users require tactile buttons and audible tones, hearing impaired users would require visual cues and of course all users could benefit from all these additional features. Adding features increase the overall cost, and keeping cost down was important. Trade-offs between features and costs were made with the addition of 4 surface mounted lights (LEDS) for visual feedback, tactile push buttons selected and a piezo buzzer added for visually impaired users (Below).
The Brains of the operations is and Arduino Nano PCB, Atmel 328p; the nice thing about these low cost circuit boards is that they already have suitable features reducing the overall bill of materials (BOM) such as voltage regulator, usb connector for debugging. And also facilities STEM because the student change the parameters of code in the ARDUINO IDE / or using a text editor and GCC.
National Instruments Multisim™ was used for the schematic capture, which then was transferred to Ultiboard™ for layout. Circuit Board Layout involves mechanically places the individual parts such as push buttons, lights and other components drawing tracks that link all the parts electrically together pictured below.
08/14/2015 at 05:03 •
From the first brain storming session a computer aided designed (CAD) model was drafted using Solidworks™. Being socially aware a design effort was made to minimise packaging where possible and as such led to the redesign the support structure and base, so that the upper support structure could be stowed in the base when not in use reducing the amount of packaging from production to deployment. Swing Arm actuation was also discussed at this phase and the choice to use a low cost 9g servo motor was made. Drawing inspiration from the hobby RC world a OEM hobby linkage rod was not only a functional choice but a cost effect alternative to designing this part from scratch.
A number of geometric iterations were made that focused on ergonomics and functionality eventually resulting in the next major design pictured below.
08/14/2015 at 04:58 •
The initial design goal was to develop a device that could dunk a tea bag in a cup for the optimum amount of tea required to brew tea. The first brain storming session yielded the following design decisions; The device had to fit on a bench top of a typical domestic kitchen and not look out of place in a home kitchen this means that materials need to be washable and wipe cleanable. Sealed woods and plastics such as acrylic and ABS were embraced for durability, availability and cost (Illustration below,  ). The device is to use standard tea bags such as Earl Grey or English Morning tea. The choice to support typical home tea and coffee cups which set the dimension of the support structure and swing arm.