EasyTrim Released!

The following picture represents the final and complete EasyTrim tool created by our group. By pressing on the corresponding link below you can view the justification relating to each of the features used in this tool.

Although the justification, for each of the features implemented in our tool, can be derived through the discussion for the creative design of the prototype, the following links provide specific references to where each feature was discussed explicitly.

(1) Aluminum Skeleton
(2) Safety Caps
(3) Non-Slipping Surface
(4) Easy Visible Charging Plug
(5) Durable Lightweight Plastic Handles
(6) Safety Catch
(7) Lightweight Rechargeable Battery
(8) Power Meter
(9) Easy Grasp Handle
(10)Non-Stick Blade

(11)Motor

Further Refinements

After analyzing the results of the evaluation methods we have reached to the following refinements for our tool EasyTrim:

EasyTrim should have a non-stick blade

Using a normal steel blade allows for non-clear and accurate cuts since the blade got easily stuck in the branch mainly due to dirt from the cuttings. This required more strength from the elderly to be used, as well as a greater amount of pressure on their wrist. Replacing the normal blade with a non-stick blade will reduce the pressure exerted on the wrist, as well as the strength needed to operate the tool.

Co-operative Evaluation: Mrs Fernandez

Day: Thursday, March 12th
Time: 11:45
Weather conditions: Mild and cloudy with occasional light rain.

The session began with Mrs Fernandez’ in high spirits and very keen to participate. The garden, 4m x 8m, appeared well kept but evidently had not been tended for several weeks as requested. Most of the flora that needed attention consisted of rose bushes, holly, geraniums and apple blossom however there was also a ornamental tree, approximately 1m high that needed attention. Mrs Fernandez speculated that it would take her up to 1 hour to complete the work with her normal tools. She also insisted that I used her first name, May.

Before beginning the work, May and I enjoyed some refreshments while she answered a few questions regarding the design of the product. Her initial thoughts were that the tool seemed "well made" and "balanced" but she needed some assurance that the tool was very safe to use.

We entered at the garden at 12:15 and May began work on the small tree. She noted that usually this gives her the most trouble as the branches are “very hard and dry”. She was very pleased at how easily the EasyTrim was able to tackle through them. She noted that her hearing is not so good and the tool is very quiet which made it hard to tell if the blade was spinning up. May was able to perform 10 cuts per minute. The average diameter of each was approximately 5mm.

Following the small tree, May moved on to a rose bush. This presented more of a challenge because the branches were thicker, thorned and significantly more fibrous causing the blade to stick regularly. May had a tendency to squeeze the handles too forcefully, shearing the branches rather than allowing the teeth to cut the fibres. I explained that somewhat unintuitvely, applying less pressure to the handles will make the task easier and prevent damage to the EasyTrim. On this task, May became frustrated and we decided to move on without completing it. On the rose bushes, May was able to perform 2 cuts per minute. The average diameter of the branch was 10mm

At this point it began to drizzle so we went inside while we a waited for the rain to subside. During this time we discussed the robustness of the tool. May was very concerned about water resistance because she occasionally she leaves things out in the rain, she also wanted to know if there was any possibility of getting “electrocuted” if she used it with hands. She also mentioned that she has a tendency to drop things accidentally or knock them off a work surface.

The rain cleared after 5 minutes and May resumed gardening. The remainder of the task consisted of small bushes and shrubs up to 0.5m high. The average branch diameter was 3-7mm. May tackled these with ease using the EasyTrim. By this time May was using the tool with great proficiency and was performing up to 13 cuts per minute. At no point during the exercise did she appear fatigued and she commented that she would normally be "out of breath" by this time. Indeed she was enjoying the activity greatly, a sentiment that she expressed three times during the course of the session. The entire task was completed in 45 minutes, 15 minutes less than anticipated.

May was thanked for her time and participation.

Conclusions:

The results and observations from the co-operative evaluation were largely positive. A number of issues have been raised.

- EasyTrim should incorporate a blade with smaller teeth so that it does not stick.
- EasyTrim should be resilient and robust enough to survive a 1m fall onto a hard surface.
- EasyTrim should be able to resist water damage from rain.
- The aesthetics are pleasing to the user.
- Battery life is more than sufficient for the user’s needs.
- Emphasise that less pressure makes the tool work more efficiently.

Co-operative Evaluation

Motivation: The co-operative evaluation is a collaborative effort between the designers and users to identify difficulties with the operation of the EasyTrim. From this we can identify issues which did not present themselves in the questionnaire and also measure qualitative data regarding the usage of the product.

Planning the Session: The session is carried out in a structured way although every effort is taken to ensure the interaction is comfortable and natural.

1. Recruit user.
2. Prepare a realistic task on the user’s own premises. The user was asked not to do any pruning in their garden for at least two weeks before the session. This allows time for adequate over-growth to occur. Performing the task in familiar surroundings is pivotal to gauging how the product will perform in real life situations.
3. The user is asked a series of pre-set questions about the product before starting their task and is invited to raise any questions that they may have with the designer.
4. The gardening session is conducted and all comments are recorded for later reference. Unexpected events are also noted as well as general observations which may be useful to the design team. A break is offered if the user appears fatigued.
5. A post session interview is carried out with preset questions.
6. User discusses their likes and dislikes with the product and raises any other issues.
7. User is thanked for their co-operation.

Cooperative Evaluation - Definition

"Cooperative evaluation" is a variant of think aloud, in which the user is encouraged to see himself as a collaborator in the evaluation rather than just a subject. As well as getting the user to think aloud, the evaluator can ask such questions as "Why?" and "What if.....?"; likewise, the user can ask the evaluator for clarification if problems arise.

Heuristic Evaluation

The goal of heuristic evaluation is to find usability problems in the design so that they can be attended to as part of an iterative design process.

Visibility of system status

The secateurs have appropriate feedback for the battery level. The power meter indicates the battery available. For better understanding the battery level has been dressed up with colors that are indicative of the power level left. The time for displaying the appropriate power level is minimum therefore the feedback is immediate.

Match between system and the real world

The product faced this heuristic well by adding an “on/off” indication on the button that starts the power tool.

User control and freedom

The product serves this heuristic well since it prevents the user from performing an operation which is unwanted, such as turning the power tool on, by adding a safety button. Even though if the power tool is turned on by mistake the control that the user has over the tool is immediate since he/she can simply re-push the same button to terminate the operation of the tool.

Consistency and standards

The product passed this heuristic. The usage of the product was clear and the meaning of the buttons and their usage was also clear. There was no ambiguity in what the operation of each button was.

Error prevention

There are not many errors that can occur during the process of using the secateurs. The only thing that can occur and the product has handle it, is in the situation where the user by accident operates the secateurs by pushing the “on” button. The product has faced this error and has successfully prevented it from happening by adding a safety button that must be released in order for mechanical part of the secateurs to operate.

Recognition rather than recall

The tool does not require the user to recall any information from a previous use of the product. The recognition of the steps required to operate the tool are visible and easily understandable.

Flexibility and efficiency of use

The speed in which the circular blade rotates is proportional to the degree of pressure exerted on the button. Therefore an experienced user can complete a task faster by using the full speed of the circular blade while an inexperienced user can operate the tool starting the rotation of the circular blade at a lower speed.


Aesthetic and minimalist design

Aesthetic of the product is similar to conventional secateur designs. The design of the product is minimalist, having only the required information that are needed to operate it present. Therefore the product satisfies this heuristic.

Help users recognize, diagnose, and recover from errors

There are no errors that can occur during the procedures required to use the power tool to achieve a goal.

Help and documentation

No documentation for the secateurs because of their simplicity.

Evaluation

For the purpose of this project we will use the following two evaluation techniques to evaluate our product:

• Heuristic Evaluation


• Cooperative Evaluation

The evaluation will consists of an interaction between the personas created and the scenario . Using this techniques we will be able to distinguish any further refinements that may be applicable to the tool EasyTrim.

Refined Prototype Design

The following picture presents the refined designed for the tool EasyTrim. This design takes into consideration the evaluation of the results of the questionnaires answered by all four personas after using the tool.

Refined Prototype Design

Critical appraisal of prototype

After we have reviewed the questionaires and scenarios we have arrived to the following refinements:

Firstly,due to the difficulty that the users faced when trying to cut branches that were a bit wider than 2 cm diameter, we have decided to enlarge the circular saw blade to a size of 5cm in order to increase the tool's efficiency.

Secondly, although the users are able to use the tool multiple times without the need to recharge the battery, battery level is proportional to the tasks that the user completes. Therefore to help them know about the remaining battery levels we will provided them with a power meter that will indicate the amount of power remaining for the tool. Considering the age group we are cuurrently working with, the power meter should be as simple as possible. It will work with three different colors instead of percentage of power in battery. The following colours with their meaning in battery power will appear:

• Green - battery full

The meter shows a full level with all five squares on the meter when battery is full.

• Orange- battery is half full

The meter shows a half full battery with three out of the five squares on the meter being orange.

• Red - Battery needs to be recharged.

The meter shows a battery that is almost empty and in need to recharge with one out of the five squares on the meter being red

Also in the case of red indication on the power meter, the light should blink so as to attract the attention of the user.

Thirdly, colors help the elderly easier distinguish the buttons. The on/off button as well as the safety button for it should be of a color that is a lot different from the skeleton of the secateur. Instead of black the color of this two buttons should become white.

The strong points:
Increased cutting power thanks to a powerful motor and a strong circular blade.
A very light model on the market thanks to the revolutionary Li-Ion battery technology.
Reduced muscular effort in the arm and shoulder.
Incomparable strength and durability thanks to a precision-forged aluminium body guaranteed for life.
A tool that is very Easy to handle and manage with carefully designed safety features.


Technical Specifications:

1. Cutting head: responds immediately when pressing the on/off button.
3. Protective frame around the circular blade to keep foreign objects out of the mechanism of the pruning shears.
4. Safety trigger.
5. Safety Catch.
6. Very strong precision-forged aluminium body, guaranteed for life
7. Pack to store away automatic secatuers and charger.
8. Easy grasp handles with non-slipping surface.
9. Battery Level.
10. Brushless, sensorless, maintenance-free motor.
11. Easy to distinguish charging plug on secatuer.
12. Safety caps above and below blade.


Circular Saw Diameter:50 mm
Average power: 150 watts (max. power: 185 watts)
Li-Ion battery capacity: 4 amperes/hour
Average duration of use without recharging: 2 working days
Mains voltage for the charger: between 90 and 250 volts
Average charging time: 5 hours
Weight of the secatuer:350g