Download Vernier Caliper Simulator
Sasha Stolt
Customise main scale divisions, vernier scale divisions and zero error using the sliders at the top right panel.
Create problem by clicking create problem button, and drag the created object near the internal jaws, external jaws or depth blade to snap, now move vernier to read its width. Controls Pinch or use keys Page Up/down to zoom.
Use mouse wheel, arrow keys or drag thimble to rotate vernier.
Calipers were designed to take external linear dimensions by contact. With less precision also measures internal dimensions, depths and protusions. In fact, for this reason it is also known as four-dimensional caliper.
To take external measures we position the object to be measured in contact with the face of the backrest of the fixed beak, the closest possible to the scale, without touching it, and gently slid the cursor with your thumb until the face of the movable backrest beak touch the object without hitting it, and without exerting too much pressure. Reading the whole value in mm is taken by comparing the mark position 0 (zero) of the cursor with fixed scale, and the decimal part by observing which mark of the cursor aligns with a trait of fixed scale. See page Vernier scale simulator to better understand this method.
The main scale of ths simulator is graduated in centimeters (1cm), which is divided by ten (millimeter). The vernier scale divide the millimeter by twenty (1/20), measuring 0.05 mm (five hundredths of a millimeter).
The main scale of this simulator is graduated in centimeter, that is divided in tenths (millimeter). The vernier divide the millimeter in fifty (1/50), marking the 0.02mm (two hundredths of a millimeter).
I have been teaching a small engine program for the past 16 years. Teaching the concept of the vernier caliper to a group of 20 students has always been a challenge. Since I have found Prof. Eduardo J. Stefanelli simulated caliper, free software on line I now find teaching this concept has been made so much easier. I use my over head projector and every one in class can now easily follow along.
The Vernier calipers model has an object (Blue) for the internal jaws to measure the width of an object with a slider to control the width of the object and simple drag action to control the position of the object.
Ever wanted to practice reading a vernier caliper but didn't have a set? No worries, now you can practice on any Android device using this free and easy app. Just slide your finger across to grip the red object and take your reading. Enter your guess and press "Check My Answer" to see if you got it right.
As an FDM printer, the Ultimaker S5 (Ultimaker BV, Geldermalsen, The Netherlands) was used with TPU 95A filament. Because the TPU 95A filament used in simulator production has a higher flexibility and elasticity compared with existing acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA), TPU 95A was chosen among the various FDM filaments.
A pilot study to determine 3D printing technology and materials was conducted to produce the rehearsal simulation phantoms. As a result of measuring 95A shore hardness by thickness using the Vernier calipers. Consequentially, although the material itself is flexible, FDM using TPU is not suitable for rehearsing LAAO because the thermoplastic material does not stretch well. It was also difficult to check the location of the device due to its opaqueness.
Still, the application of 3D printing technology requires more cost and time, so it should be considered and applied reasonably. Flexible and transparent materials were selected in order to simulate the phantom with materials having properties similar to those of human tissue, considering the reasonable cost for manufacturing patient-specific phantoms. TPU of FDM 3D printer is a polymer-based material with some flexibility. Compared to SLA materials, this is not as flexible and transparent, so it could not be applied to actual rehearsals. Therefore, in this study, we used the flexible material of SLA has relatively good elasticity and transparency enough to see the positioning of the LAAO device from the outside, which could be a novelty of our method. In addition, the implementation of the physical properties of the actual human anatomical structure was attempted in order to show that the handling of the procedure can be similar. The material was decided upon by collecting the opinions of two cardiologists, referring to the shore A hardness of 3D printing materials with a texture similar to that handled in the actual treatment. Although it is difficult to apply this study to actual clinical practice right now due to costs or healthcare reimbursement, this method with 3D printing technology could have a potential to supplement current medical cares like an educational simulator for medical students and intervention fields with high image dependence.
This study had several limitations. First, only two medical doctors evaluated the suitability of the materials. In addition, despite an estimated 3-y study, the number of LAAOs was not sufficiently large, with only 10 patients enrolled. Therefore, there is a need to evaluate this phantom with more anatomical diversity of various kinds of LAAO patients in future studies. It should also be evaluated by the various cardiologists and by collecting various opinions through questionnaires. Second, it was difficult to accurately implement the texture of the actual human body with the currently available 3D printing materials. Therefore, to reflect physical properties more similar to that of the actual human body, it is necessary to develop silicon and similar 3D printing materials. Third, there was a limitation in the measurements performed for comparing the accuracy between the STL file and the 3D-printed phantom. There were outliers where a value outside the 95% confidence range appeared, as shown in Fig. 6. To make it similar to the physical properties of the actual heart tissue, it was manufactured to be as thin and flexible as possible; thus, the measurement value may not be constant, depending on the operator who uses the Vernier caliper when measuring. In particular, the landmark C in Fig. 5 is a measurement of the vertical area of the orifice, which was very difficult to measure using Vernier calipers due to the shape of the area and the material characteristics of the phantom. However, in the actual procedure, the accuracy of the device size prediction of the 3D printing phantom was very high because a circular device that filled in the LAA orifice was inserted. Fifth, the size of the LAA in the CT image may not have been fully reflected in some cases, depending on the patient's condition at the time of the CT scan. Therefore, CT scans prior to the procedure should be performed with caution. In conclusion, this rehearsal simulation using a 3D-printed LAAO phantom more accurate device size selection is possible because the 3D shape and architecture can be evaluated using the 3D-printed phantom, compared to the conventional method that predicted the device size using only CT and TEE.
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