IEEE Robotics & Automation Magazine - September 2021 - 80

open-ended situations using virtual labs, at least in their
current form [4].
Researchers have also investigated the use of a single set of
hardware that students can operate remotely over the web.
For example, Gillet et al. described using a number of electromechanical
systems, including an inverted pendulum and a
model helicopter, to allow students to remotely adjust controller
parameters and view the system responses [8]. This setup
provided students with practical experience in control engineering
without requiring them to be in the same location or
have their own hardware.
There have been a few examples of equipment that aimed
to enable each student to have individual hardware at his or
her remote location. For example, two take-home lab kits,
consisting of a mass-spring-damper system and an analog filter
system, were developed and distributed to students to
take home and use similarly to regular assignments [9].
However, this pilot project was not designed with the intent
for the devices to be distributed on a larger scale. Similarly,
the Andruino-A1 is a low-cost, modular, and extendable
mobile robot that students can construct and program
themselves. It was designed for use in both classroom and
online courses but, to date, has been used only in a traditional
classroom [10].
Educational Haptic Devices
Most commercial haptic devices are too expensive and complex
for a classroom setting. In addition, they are usually proprietary,
making it difficult for users to modify or extend the
hardware to enhance learning. In 2002, researchers at Stanford
University designed a simple 1-DoF device, called the
Haptic Paddle, for use in a dynamic systems course [11] [Figure
2(a)]. Students used the device to interact with virtual
environments and learn how to model, analyze, and control
dynamic systems. Due to the success of integrating a lowercost
haptic device with a standard engineering course, several
other universities adopted the idea, modifying the Haptic
Paddle to better fit their teaching objectives [12].
There are several features common to all Haptic Paddles to
date. First, they are 1-DoF devices, keeping the cost relatively
low compared to typical 3-DoF commercial devices. Additionally,
they are impedance-type force-feedback devices driven
by an electromagnetic actuator. Finally, the user typically
interacts with them through a joystick-like handle. Several
versions of the Haptic Paddle are shown in Figure 2. The
design of each reflects the differences in learning objectives as
well as intended audience.
Hapkit Device
Hapkit, shown in Figure 1, is a 1-DoF, kinesthetic haptic
device. The name, Hapkit, is derived from " haptic kit, "
because students start with a kit that has the components
needed to assemble the device themselves. To ensure that students
could assemble, program, and interact with this device
in an online learning environment without an instructor
physically present, we implemented a number of important
design changes and features compared to the original Haptic
Paddle. We highlight the features for two iterations of
the design-Hapkit 1.0 and Hapkit 2.0-which were created
for use in a guided, online pilot course and a self-paced
MOOC, respectively. A list of parts and prices can be found
at http://hapkit.stanford.edu, and the approximate total cost
of parts and tools for Hapkit 1.0 and 2.0 was US$100 and
US$50, respectively.
Handle Stop
MR Sensor
Neoprene for
Friction Drive
Drive Wheel
SD Card
Reader
Bar to Adjust
Amount of Friction
Micro-USB
Port
Mechanical Design: Hapkit 1.0
Three main factors drove the device design: cost, learning
environment, and users. First, because students would ultimately
purchase the kit themselves, it
was important that the device be as
inexpensive as possible. Second, unlike
standard in-person learning environments,
there would not be an instructor
physically present, so the design
needed to be self-explanatory and easy
to assemble using only household
tools. Third, the design had to be
accessible to users from a wide range
of backgrounds, including those without
any prior building experience.
Step-by-Step Assembly
Unlike previous Haptic Paddles, Hapkit
was intended for students to build comMagnet
for
Position Sensing
Custom Arduino Clone
Figure 1. A fully assembled, 1-DoF, low-cost, open source haptic device, Hapkit, used in
hands-on laboratories in an online course. Design features that ensure students could
assemble, program, and interact with this device in an online learning environment are
highlighted. MR: magnetoresistive; SD: Secure Digital.
80 * IEEE ROBOTICS & AUTOMATION MAGAZINE * SEPTEMBER 2021
pletely on their own using a kit, shown in
Figure 3(a), which includes all of the
components and tools necessary for
assembly. The main body of Hapkit is
made of laser-cut acrylic pieces. To ease
assembly, a number is etched onto each
http://hapkit.stanford.edu
IEEE Robotics & Automation Magazine - September 2021

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