marveldex MDXS-16-5610 User manual

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(J200712) Manual - Cushion Sensor Coding Kit
Marveldex Inc.
Manual - Cushion sensor coding kit
How to use
Reference documents / sites
In addition to the components of this product, the user must additionally prepare a USB cable, a PC, and a simple cushion (or thick cloth if there is no
cushion). This sensor is used inside/under a seat cushion. There are various methods to measure the output of the cushion sensor, but in this document,
it is measured through the Arduino circuit. It provides basic source code for Arduino and PC, and users can modify the source code.
Precaution is at the end of this document.
Model : Cushion sensor coding kit
Cushion sensor coding kit
Introduction
This product is a measurement kit that collects the pressure distribution data of a
seated person on a chair.
The product composition is as follows. (See page 4)
(1) Cushion type pressure sensor
(2) Arduino for measurement
(3) Arduino shield for connecting and measuring sensors and circuits
The cushion sensor consists of 31 individual pressure sensors.
You can get information about the sitting posture from the measured values at 31
positions.
This product provides the basic H/W and S/W necessary to measure and show data.
You can develop various application solutions using the measured data.
< Challengeable applications >
This kit can be used
-To develop healthcare solution : Monitor sitting posture to warn bad posture
-To develop input device : With the tilting information, you can generate a direction
key events and utilizes it as a VR (Virtual Reality) or game controller.
-To design ergonomic cushion/chair
-To develop for the disabled
It is possible to understand basic principles and implement with only this document. Additional resources or examples can be found at the link below.
Go to the document library: https://bit.ly/2WliDm4
Source code example blog: https://bit.ly/2ZwEkBM
Update : 12/July/2020
Seated posture measured with this kit and displayed on a PC screen
SW development environment: Arduino, Processing

Data usage example
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Cushion sensor recognition examples
Model : Cushion sensor coding kit
You can understand the tendency of the sitting posture through the measurement values of
the 31 cells in the cushion sensor. The measuring range of one sensor cell is about 20gf to 4Kgf.
The actual load applied to one sensor is usually within 3 Kgf, as the load of the seated person
spreads across the whole chair and the load is distributed due to the softness of the cushion.
For this reason, even if the load of the seated person is as high as 130kg, pressure measure-
ment and posture recognition are possible.
Recognizable seating poses include left/right tilt, degree of tilt, legs-crossed etc.
Low Load High Load
Right tilted posture and measurement results Left tilted posture and measurement results
Back tilted posture and measurement results Forward tilted posture and measurement results
Posture with crossing right leg Posture with crossing left leg
Coding for Measurement :
see pages 6-17 of this document
Load and color map
Empty Strong Press
(J200712) Manual - Cushion Sensor Coding Kit
High load
on the right
High load
on the left
High loads behind
High loads in front
The measurement on the right leg is zero The measured value of the left leg is zero
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There may be an error in the attitude recognized/determined by this cushion sensor. Factors affecting: siting body shape, chair/cushion shape, material, etc.
Figure) Measured values in normal posture.
Most of the 31 cells look light green and yellow.

HID
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Table of Contents
Model : Cushion sensor coding kit
Length = 380 mm
Width = 388 mm
Kit composition, dimension ..................Page 4 ~ 6
Posture recognition and Visualization SW .........Page 13 ~ 17
Arduino configuration, measurement .......Page 10~12
Expansion of circuit and challenges ........Page 18~20
Processing.org
VR
(J200712) Manual - Cushion Sensor Coding Kit
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Sensor technical info, Precautions .................Page 21, 22
V in
GND
Ra (Sensor)
Rc
V out
(ADC)
Cushion sensor shield and circuit study .............Page 7 ~ 9

(J200712) Manual - Cushion Sensor Coding Kit
Name: Cushion Sensor Shield
Role: Role : To connect sensor and select a cell
Two analog switches and pulldown resistor for
ADC measurement are included inside.
Accessories for assembly
Cushion sensor (Model : MDXS-16-5610)
rubber form tape
Kit component
Assembly-cushion sensor, shield, arduino
After tightening the bolt.
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Connecting the cushion sensor to the Arduino
Model : Cushion sensor coding kit
Name: Arduino Pro Micro (or Nano)
Role: Measure the cushion sensor 31 channels.
Be sure to install the driver before connecting
the USB to the PC. (See pages 10 and 11)
Top view Bottom view
Arduino Pro Micro
(or Nano)
Cushion Sensor Shield
Bolt x 4ea
Nut x 4ea
rubber form tape
guide plate
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Wrench
Bolt x 4ea
Nut x 4ea
Wrench
Cushion sensor
guide plate

Cushion top Turn the cushion upside down, and
open the zipper.
Size comparison-sensor and cushion
Open the zipper and insert the
sensor upside-down as you see.
If the cable folds inside the cushion,
it may cause a measurement error.
Make a small hole on the cover.
Pull out USB cable through a
hole
Close the zipper. Done!
(J200712) Manual - Cushion Sensor Coding Kit
Insertion sequence
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Put the sensor into the cushion
Model : Cushion sensor coding kit
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Connect the Micro USB cable
to the shield.
Close the zipper after putting
it all in.
Turn the cushion over again and place it on
the chair with the top side up.
Sit down now.
1
2
3
4
It is not necessary to put the sensor in the cushion. You can also place the sensor under the cushion. However, make sure that the hard and protruding
parts, such as zippers, do not press the sensor's measurement area.
Healthcare cushion Cushion smaller than the sensor fabric/foam/blanket
The material inside the cushion should be
soft, such as sponge, memory foam, and co-
tton.

DescriptionUnit
Length
Width
Thickness
Sensing range
(per cell)
Number of cells
380mm
388mm
0.95mm
20gf ~ 4Kgf
31
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Top view
Let's find out why we placed 31 sensors in three rows and why we
placed more cells in the middle row of three rows. The occupant's
load is widely distributed, but not entire the chair.
The load is intensively applied mainly around the hip bone. (Picture
on the right) For this reason, the pressure distribution of the occupa-
nt is usually concentrated in the position of the hip bone, as shown in
the left figure below.
The load applied to the thigh area is relatively low.
Figure) The load is intensively
applied to the two hip bones.
Figure) siting load distribution and cell placement. A lot
of sensors placed in the hip area. The sensor on the thigh
detects whether the thigh has touched the chair
Figure) Typical load distribution of seated persons.
Sensing zone
Intermediate zone
Dead zone
Prime Sensing zone
Sensor dimension, Cell placement
Model : Cushion sensor coding kit
(J200712) Manual - Cushion Sensor Coding Kit
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sales @ mdex.co.kr
Marveldex Inc.
Length = 380 mm
Width = 388 mm
MDEX .CO. KR MDXS-16-5600
Pads = 108 mm
Sensor dimensions
About Cell Placement
Summary
thighthigh
HIP
Tailbone
Width of 1 cell
Length of 1 cell
19 or 38mm
19mm

Composition of cushion sensor shield-socket, pad for sensor connection, analog switch
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.
Model : Cushion sensor coding kit
(J200712) Manual - Cushion Sensor Coding Kit
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Marveldex Inc.
Top View
Bottom
View
Figure) Arduino Promicro plugged into the socket of the cushion sensor shield. (Arduino genuine is red while compatible is blue)
: Cushion sensor connection / 32 fixing pads
: 2 ea of built-in 4to16 analog switches
En0
En1
S0
S1
S2
S3
GND
GND
VCC
ADC
32CH SEAT SHIELD - V.1.0
MDEX.CO.KR
Shield for Arduino
Promicro, Nano, UNO.
H0
H1
H2
H3
H4
H5
H6
H7
H8
H9
H10
H11
H12
H13
H14
H15
H16
H17
H18
H19
H20
H21
H22
H23
H24
H25
H26
H27
H28
H29
H30
H31
VCC
Number of 31 cells (0~30) and data transmission protocol
Top view
vcc
The sensor numbers on the left are connected according to the terminal numbers (0 to 30)
in the figure below.
The sensor measurement values are transmitted in the order of the terminal number.
Terminal number
Cushion sensor shield for Arduino
Circuit) Shield for Arduino and terminal

Schematic of cushion sensor shield
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Circuit) Sensor shield - 1
Model : Cushion sensor coding kit
Two analog switches (74HC4067; 4 to 16) are built in the cushion sensor shield.
32 sensors (H0~H31 below) can be connected by 6 GPIOs (S0 ~ S3, En0, En1 below).
(J200712) Manual - Cushion Sensor Coding Kit
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Marveldex Inc.
V cc
GND
Rsensor
Rc (pull down)
V out
(ADC)
Measuring 1 sensor cell
-ADC circuit
One ADC terminal and one pull-down
resistor are required.
GPIO x 6
ADC x 1 V out = Rc x V cc
Rsensor + Rc
4 to 16
Analog switch
(74HC4067)
4 to 16
Analog switch
(74HC4067)
En 0
ADC
En 1 S 0 S 1 S 2 S 3

Table) How to set GPIO pin by cushion cell number
En : Enable Negative
S0~S3 : Signal
Selecting the 20th cell in the cushion sensor shield
74HC4067 Switch Description. Connect 16 cells with 4 signal pins.
Ex) How to set 6 pins to select the 20th cell
Cell selection example
- 20th cell
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Circuit) Sensor shield - 2
Model : Cushion sensor coding kit
(J200712) Manual - Cushion Sensor Coding Kit
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En 0 En 1 S0 S1 S2 S3
H0 0 1 0 0 0 0
H1 0 1 1 0 0 0
H2 0 1 0 1 0 0
H3 0 1 1 1 0 0
H4 0 1 0 0 1 0
H5 0 1 1 0 1 0
H6 0 1 0 1 1 0
H7 0 1 1 1 1 0
H8 0 1 0 0 0 1
H9 0 1 1 0 0 1
H10 0 1 0 1 0 1
H11 0 1 1 1 0 1
H12 0 1 0 0 1 1
H13 0 1 1 0 1 1
H14 0 1 0 1 1 1
H15 0 1 1 1 1 1
En 0 En 1 S0 S1 S2 S3
H16 1 0 0 0 0 0
H17 1 0 1 0 0 0
H18 1 0 0 1 0 0
H19 1 0 1 1 0 0
H20 1 0 0 0 1 0
H21 1 0 1 0 1 0
H22 1 0 0 1 1 0
H23 1 0 1 1 1 0
H24 1 0 0 0 0 1
H25 1 0 1 0 0 1
H26 1 0 0 1 0 1
H27 1 0 1 1 0 1
H28 1 0 0 0 1 1
H29 1 0 1 0 1 1
H30 1 0 0 1 1 1
H31 1 0 1 1 1 1
20th cell
0
0
1
0
1 0
0
0
1
0
1: Disabled 0: Enabled
Pin setting to select 20th cell
( En0=1, En1=0, S0=0, S1=0, S2=1, S3=0 )
X O

Arduino setup & configure
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Connect Arduino to PC
Model : Cushion sensor coding kit
Link to Arduino installation file - https://www.arduino.cc/en/Main/Software
File> Preferences> Settings tab and copy/paste the following address into the ‘Additional Boards Manager URL’s field.
If you are using Arduino Nano or Uno, the following steps are not necessary.
Tools> Board> Board manager> Search for'sparkfun AVR' in the search bar> Click the'Install' button
Install sparkfun AVR in Board manager
https://raw.githubusercontent.com/sparkfun/Arduino_Boards/master/IDE_Board_Manager/package_sparkfun_index.json
(J200712) Manual - Cushion Sensor Coding Kit
http://en.mdex-shop.com
sales @ mdex.co.kr
Marveldex Inc.
Arduino Configuration - Adding an Arduino Pro Micro Board
Install Arduino Pro Micro Package
COPY
PASTE