From DDL Wiki

Contents 1 Executive Summary 2 Research and Observations 2.1 Usability Study 2.2 Market Research 2.3 Areas for Improvement 3 Design Concepts 3.1 Concept 1 3.2 Concept 2 3.3 Concept 3 3.4 Concept 4 4 Design Schedule/Gantt Chart 5 Recommendation Summary 6 Team Members

Executive Summary

Research and Observations

Usability Study

In order to get a better understanding of how the user interacts with our product, we conducted two usability studies. To broaden our knowledge on the use of the tool, we chose to examine two subjects -- one male and one female, both college aged. Each user study was conducted in the exact same manner. The user dug a total of 4 holes; 2 with the simple post hole digger and 2 with the complex post hole digger. Of the 2 holes dug with each tool, one was in hard, grassy soil, the other in soft topsoil. The user first dug for 5 minutes in hard, grassy soil using the simple post hole digger. He or she was then given a few minutes to rest, and moved on to digging another hole for 5 minutes with the complex post hole digger. This hole was strategically dug in an area nearby the previous one to maintain a common consistency of the soil. After another brief rest, he or she moved to the soft topsoil. The user dug with the simple tool until 5 minutes was up or a depth of 36” was reached, resting only after this milestone. Lastly, the subject dug in the soft topsoil with the complex digger for 5 minutes or until the 36” depth was reached. Again, the hole was dug near the first one made in the soft topsoil to ensure common soil consistency. Throughout all of the experiments the group members noted the user’s actions, comments, and depth of the hole throughout the process. After finishing the physical testing, the group asked the user to comment on the experience, while also asking specific questions to help prompt them for a particular type of response. A detailed rundown of each study can be found in the following paragraphs.

Study I: Average Female User

Name of Subject: Laurel Bancroft

Age: 21

Height: 5’ – 4”

Weight: 120 lbs.

Date: Friday, 9/26/08

Test 1: Simple post hole digger in hard, grassy soil

Observations made by group:

From the beginning of this test, it was immediately apparent that the soil was going to be quite difficult to dig. After encountering several rocks and a few roots, the user was only able to dig to a depth of 3" after the 5 minute time limit was reached. Throughout the entire experiment the subject struggled with actually removing the dirt from the hole. As the dirt continued to fall out of the shovel before removal, the user became visibly frustrated.

User comments:

Most of the comments made by the user during the test were fully expected, and helped solidify many initial thoughts and concerns we had with the simple post hole digger. Some of the issues she had with the tool included: banging her knuckles together, difficulty aiming and hitting the hole, fatigue from the weight of the digger, and the fact that the dirt failed to remain in the shovels during removal. She also mentioned that the misalignment of the handles annoyed her, and suggested the use of gloves with the tool.

Test 2: Complex post hole digger in hard, grassy soil

Observations made by group:

This test immediately showed the lack of mechanical advantage as the user struggled to even close the digging heads after penetrating the soil. The subject did do something fairly unexpected and quite interesting to make up for her lack of strength. Rather than pulling the handles apart with both arms from a centered location, she stood to the side of the tool, pushing with one hand and pulling with the other. This phenomenon is depicted in Figure 2.1.3. On top of this, she also experimented on when to pull the handles apart. Rather than pulling the handles apart immediately and getting the tips of the digging heads stuck on the hard soil at the bottom of the hole, she pulled the whole tool up a bit before closing the digging heads. This allowed her to extract the loose soil in the hole without catching the shovel on the bottom. Another interesting technique employed by the subject occurred when entering the soil. When thrusting the tool downward into the ground, the she held the tool near the middle of its handles rather than the top where its grips are located. Once in the hole, she then moved her hands to the grips to pull the handles apart and extract the dirt. Figure 2.1.4 shows the user utilizing this tactic. Perhaps her experimentation paid off since the digging rate seemed higher for the complex post hole digger. During this test, the user reached 4" after just 3 minutes, ending up at 6" when time expired. She more or less doubled her digging rate with this tool.

User comments:

Again, most of the comments made by the user during the test were fully expected. Because she is fairly short, she struggled with the long handles, as demonstrated by Figure 2.1.4. She mentioned that the tool seemed heavier than the simple digger, and she became fatigued much more quickly. Besides these two complaints, her comments were generally positive. She appreciated the knuckle protecting mechanism, liked the sharper tips on the digging head, noting that it enabled her to pierce the ground more easily, and had less trouble aiming the tool in the hole. One bit of humor that arose from one of her comments came when she refused to kill a worm that appeared in the hole. She refused to continue until one of the members removed it.

General user comments prior to tests 3 and 4:

Before proceeding to the 3^rd and 4^th tests, we chose to ask the subject for a few general comments based off the performance of the two diggers in the hard, grassy soil. The user noted that if the simple shovel was aligned more accurately and had sharper tips, she’d rather use it because of its light weight. Her reasoning behind this was that she'd personally prefer to use a lighter tool and sacrifice the higher number of reps vs. using a heavier tool requiring fewer strokes. When asked if she had to dig a 6” hole in hard, grassy soil right now, she said she’d choose the complex digger, mostly because her digging rate was twice that of the simple digger.

Test 3: Simple post hole digger in soft topsoil

Observations made by group:

This particular test went much better than expected. Because the soil was quite loose at all depths, the subject was able to dig to a depth of 36" in just 4 minutes, completely blowing away her performance in the hard, grassy soil. Despite this overall success, the test did show some negative results. Once a depth of about 16" was reached, the user began having issues aiming. After this point, she repeatedly hit the top edge of the hole, caving it in, stroke after stroke. Figure 2.1.5 shows how sloppy the entry to the hole became as the user slowly destroyed it. Also, when the hole became roughly 24" deep, the handles of the digger began hitting the sides of the hole. This phenomenon is depicted in Figure 2.1.6. Throughout the entire experiment the subject struggled with actually removing the dirt from the hole. As the dirt continued to fall out of the shovel before removal, the user became visibly frustrated.

User comments:

As evidenced by her repeated failure to hit the hole, the subject admitted that she had trouble aiming as the hole became deeper. As a result of slowly caving the top of the hole in, she became timid with her penetrating thrust. She felt that if she slowed her self down a bit, she'd become more accurate. Once she did this, she did become much more accurate with her strokes. Besides these negative aspects, she repeatedly commented on how much simpler it was to dig in the soft soil. She was quite proud of her performance.

Test 4: Complex post hole digger in soft topsoil

Observations made by group:

Much like was the case with the simple digger, the complex digger performed much faster in the soft soil than it did in the hard, grassy soil. Because of its ability to scoop more dirt in one pass, the subject's digging rate was even faster than that of the simple digger in soft soil. After 1 minute, she'd already reached a depth of 18". At this point, the user reverted to an old technique as discovered in test 1. She began standing aside the tool again, pushing with one hand and pulling with the other. Because the hole was much deeper, she added a slight twist in this technique by turning the hand with which she pushed, upside down. She can be seen doing this in Figure 2.1.7. As the hole became deeper, it became obvious that the increased length of the complex digger compared to that of the simple digger was becoming a problem. She eventually dug by initially grabbing the handles on the grips to get the dirt half way up the hole, but because she was too short to get the entire tool out she tried moving her grip down to the middle of the handles to extract the dirt. This technique often failed, causing a good portion of it to fall out of the shovel. One result worth noting was that, at a depth of 36", the handles of the complex digger came close to, but did not touch the edge of the hole (see Figure 2.1.8). This was interesting to us, because when purchasing the tool this phenomenon was one of its main points of advantage that it claimed over other designs.

User comments:

-Because you can get so much more dirt with one scoop, it’s pretty heavy, so it seems a bit harder to use than the simple digger -I’m noticing now that this tool is heavier than the other. Again, the ability to dig more per scoop is really tiring me out. -When the hole gets really deep, it’s hard to get the dirt out since I’m short. Also, bending over is not fun.

General user comments at this point:

-The complex tool’s handles are a little too long -When digging a 36” hole, I’d much rather use the simple digger. Any deeper though, then I’d go with the complex digger. -The simple tool is much easier to pull apart than the complex tool. It seems like the complex tool tends to stick when trying to pull it apart. -The sharp tips of the complex digger and its ability to completely close are great attributes, but it’s not really applicable to soft soil digging. -The diameters of the handles of each tool were a little too big. They make my hands hurt. -I like the fact that you can’t bust your knuckles using the complex digger -I personally think the wood handle would splinter really easily -I think the simple digger would definitely break first -When the idea of using a gas powered auger was proposed, she said just not knowing how to use one would completely deter her from using it, plus the danger involved was not appealing. She’d go with the mechanical version instead. -When asked which tool she would choose in a store and why, she said she would’ve chosen the complex digger for the following reasons: -The sharp tips allow you to get better penetration -I would’ve assumed they were both the same weight even though the complex tool was quite a bit larger. It just seems like it’s made of more high-tech material and wouldn’t weigh any more than the simple digger. -Since the complex one was 2x’s as much money, I would assume that expense = a better product

Market Research

Areas for Improvement

Design Concepts

Concept 1

Concept 2

Concept 3

Concept 4

Design Schedule/Gantt Chart

Recommendation Summary

Team Members