Gadget Renesas

Linking Ideas and Electronics

GR Atelier

Title:Making of lighting probe - welfare device using GR-KURUMI

Displayed Name:Mamoru Sakaki

Making of lighting probe - welfare device using GR-KURUMI

Concept / Overview
The students in blind schools usually use “Lighting Probe” which has brightness and darkness sensor for their science experiments.

“Lighting Probe” costs \50,000 per set, it prevents their own possessions. GR-KURUMI enable you to assemble kits with the materials cost only \5,000, it allows them to have in individuals. also they can use them in their daily life even after graduation.

“Lighting Probe” is useful to perceive PC power on/off, lighting power on/off in the room. Further, it is expected to be applied in a wide range of fields such as position checking of the candle flame on altars, perception of the white line on cross-walk by putting it on the tip of sticks.

Main components

  • GR-KURUMI \2,200
  • GHA Handheld plastic case Takachi GHA4-3-11PB \440
  • Battery charger for Li-ion (Small size) SFE-PRT-10401 \ 990
  • Li-ion polymer battery 110m AhSFE-PRT-00731 \600
  • Electric wire vs. boards housing Molex 5051-02(2P), 5051-03(3P) Sengoku \30
  • Mini slights 6P center off Imakawa Ele 0695-00 Maltsu parts \110
  • Piezoelectric speaker Akizukidenshi P-04118 \30
  • Photo IC diode Hamamatsu Photonics S9648 (Akizukidenshi I-03825) \400 (5P)
  • Less power loss CMOS three terminals regulator 3.3v 50mA 
    Seiko instruments S-812C33AY-B-G (Akizukidenshi I-03289) \100


(Others)Mounting screws for switch (M2), IC sockets, Tapping screws to secure the boards and Washers made of polyethylene.



Photo diode



To have visually handicapped students realize, select main components and connectors capable of connecting and assembling by insertion.




In prototype stage, making holes by hand either for USB jack or switch, manual processing with a hand tool has a limit.

Introducing the new equipment “Oh Laser” has realized improvement of the precision and shortening the time on processing. Using a 1.6mm acrylic board shortly after laser processing.



CAD Data:sakakiGHA4-3-11.dxf [Download]



Using a 1.6mm acrylic board shortly after laser processing.



Downloaded the CAD data from Takachi Electronics Enclosure Co.,Ltd.
Downloaded the shape of mini-USB from RS Components
 RS Components> Connectors > USB, D-sub & Computing > Mini USB Connectors
Re-designed the side plate by CAD.
Converted to Auto Cad file
And converted to Corel Draw file.
Finally to Oh Laser HAJIME






Circuits diagram

Eventually we choose photo diode made by Hamamatsu photonics, though we have another option to use photo transistor + smart analog for prototype stage.

Connected to A3 port on GR-KURUMi for brightness.

Using Design spark PCB 7.1 as design circuits.

Three terminals regulators are used to stable voltage for photo diode.

Applied Li-ion battery for compact and lightweight on welfare devices.




Red data shows outdoors mode, blue one shows indoor. 6P switch selects the mode by changing variables of the function in programs. 

Struggling for setting function and its coefficient, left many for further Improvement. 

Outdoors mode, you can recognize the difference between sunny and shadow areas since musical scale change even under high Illumination.

Simulated the function and its variables by Maxima that has been distributed on the web free of charge.






No. 1

/*GR-KURUMI Sketch Template Version: V1.06*/
// sirial–³‚µ//
	int scaleA[]={28,29,31,33,35,37,39,41,44,46,49,52,
int led_red   = 22; // LOW active
int led_green = 23; // LOW active


int scaleno1=0;
int sp = A3;
int scale=1;
int j=0;
int sw=0;
int scaleref=1;
double p=0;
double m1=0;
double m2=0;
double m3=0;
double marin=1;
double yuki=350;
double kei=116;

void setup() {


  pinMode(sp, OUTPUT);
  pinMode(A0, INPUT);
  pinMode(A2, INPUT);
  pinMode(led_red, OUTPUT);
  pinMode(led_green, OUTPUT);
  int indata = analogRead(A0); 


void loop() {
        digitalWrite(led_red, 0);


int total=0;
for(j=1;j<=5;j++){          //5回分合計
	int indata=analogRead(A0);    //A0番ピンからの値をaに代入    
	double p=indata;

	m2=pow(marin, m1); 
	int m4=m3;

	scaleno1=(3+total/5);      //5回分のデータの平均

	if(scaleno1==scaleref){      //scaleno1とscalerefが等しいとき
		scale=scaleA[scaleno1]; //scaleAのscaleno1番目の周波数をscaleに代入
		scaleref=scaleno1;       //scaleno1をscalerefに代入
		//  tone(sp,scale,0);





Making of print circuit board (PCB)

Print circuit board (GND pattern)




using Design Spark PCB 7.1 (good practice against aging).

Embedded circuit into plastic case GHA4-3-11PB, hole pattern with dimension is available from Takachi website, though conversion is required depend on the size of PCB.



The price of PCB is not much different with 50 units or even 100units. 
Will give light proves as gifts to all students who help testing.

Gerver file: 2015@7@13C - Bottom Copper (Paste).zip [Download]




Light and shade recognition performance on paper.


Light and shade recognition performance in the room.



Light and shade recognition performance outdoors.



Closing remarks

as of Feb 2016, just finished evaluation on customer satisfaction for this welfare device, to have several blind persons try using prototype for a week in the rehabilitation center.

In free discussion,

  • "Lighting probe is convenient since it’s ready to use, comparing using the application in iPhone."
  • "It’s useful to perceive lighting power on/off in the room I left alone."
  • "We can perceive PC power on/off when we point lighting probe toward PC."

how to use in daily life, the voice of the person who tried it as aboves.

Still left many for further Improvement on device, if it is a good opportunity to be interested in making such welfare device, we are happy.

MVP information Mamoru Sakaki
  • From Hokkaido, over 50, an ordinary person with a son, one of my favorites is Japanese sake called "Daiginjo". Moved from Kushiro in Hokkaido to Ibaraki here in 2000, working as the boss in laboratory of the university. "Time flies like an arrow." my son is the same age as students in my laboratory.
  • Learning about human nature through the interchange, physical property through the research on surface reforming with the students in neighboring blind school.
  • With GR-KURUMI, pondering if we can make interface for switch device which handicapped students use for iPhone,I eager for contribution to the society.
  • The picture shows the postmortem session with a research student and my son in Shimokitazawa after Renesas night in Dec 2014.
  • With Kindle application, digital reading gives me the great pleasure during commuting time.