Recupération d'un afficheur LED à décalage : Différence entre versions

Version du 29 janvier 2019 à 21:55

Une Technique de Sylvain dans les catégories Électronique. Dernière modification le 22/04/2022 par Sgiraud.

Réutiliser un afficheur LED digital pour des projets Arduino. Exemple avec 4 registres à décalage HC164

Difficulté

Facile

Durée

1 heure(s)

Coût

2 EUR (€)

Sommaire

1 Introduction
2 Etape n°1 - Récupérer le display
3 Etape n°2 - Trouver les registres à décalages
4 Etape n°3 - Recherche de la masse
5 Etape n°4 - Recherche de l'alimentation +5V
6 Etape n°5 - Recherche du Clk et Data
7 Etape n°6 - Connexion à l'Arduino
8 Etape n°7 - Le Code
9 Notes et références

Licence : Attribution (CC BY)

Mot(s)-clé(s) : Registre à décalage, affichage, LED, 7 segments, display, Réutilisation, Récupération, HC164

Introduction

Il est courant de trouver dans les bacs de récupération des afficheurs 7 segments LED avec registre à décalage. La connexion à ses afficheurs est simple, elle n'a besoin que de 2 fils: clock et data. L'Arduino est parfaitement adapté pour générer les bons signaux.

Liste des matériaux

1 Display à LED 7 segment et Registre à décalage

Des fils avec connecteurs

Liste des outils

1 fer à souder

De quoi dessouder ou couper une connexion

1 Arduino Nano

1 Testeur (Voltmètre/Ohmmètre)

En option 1 shield Nano

Etape n°1 - Récupérer le display

Par exemple, ici, le display provient d'une carte de climatiseur. Il y a 4 x 8 segments, avec 3 x 3 connecteurs bien visibles. Le 8ieme segment correspond au point après chaque chiffre. On ne voit pas les registres, mais il y en a très probablement puisqu'il n'y a que 7 connecteurs (hors masse et alimentation) pour 32 segments.

Reste à dessouder les 9 connecteurs, ou (plus rapide) les couper à la pince.

Recup ration d un afficheur LED d calage Airwell-911A193-12.JPG

Recup ration d un afficheur LED d calage IMG 20190126 093915.jpg

Etape n°2 - Trouver les registres à décalages

Il y a bien 4 chips derrière, qui correspondent à chacun des chiffres de l'afficheur. Après nettoyage et avec une bonne loupe, on arrive à lire "HC164". C'est une registre à décalage très courant et simple.

La doc est facile à trouver (voir ci-joint) et le principe simple:

A chaque transition sur le pin CLK (Clock)
La valeur en entrée DATA est "poussée" dans le registre et décale les 8 bits qui y étaient déjà.
Le 8ieme bit est chainé sur l'entrée DATA du registre suivant
Ainsi, après 8 x 4 = 32 transitions, tous les bits des 4 display sont valorisés.

Recup ration d un afficheur LED d calage 4xHC164.jpg

Recup ration d un afficheur LED d calage HC164-diag.png

Etape n°3 - Recherche de la masse

La carte est multi-couches, donc assez compliqué de s'y retrouver dans le circuit. En testant la connectivité entre les connecteurs, 4 connecteurs s'avèrent en lien direct (résistance nulle): les 3 du haut (CON3) et celui au centre à droite (CON1). Ceux-ci sont visiblement connectés sur le circuit à de grandes surfaces conductrices qui est très probablement la masse.

Recup ration d un afficheur LED d calage CHILLER-DISP-gnd.jpg

Recup ration d un afficheur LED d calage IMG 20190126 160436 1.jpg

Etape n°4 - Recherche de l'alimentation +5V

Plus simple qu'il n'y parait: en général sur le circuit, le VCC est visualisé par une gravure "carrée". Justement, il y a un lien entre un carré sur le circuit et le connecteur le plus bas du CON1.

On peut alimenter ! Les LED vont s'afficher un peu au hasard au gré des mauvais contacts et parasites.

Victoire!

Recup ration d un afficheur LED d calage 5VCC.png

Recup ration d un afficheur LED d calage alim.jpg

Etape n°5 - Recherche du Clk et Data

Plusieurs méthodes:

Suivre les circuits CLK et DATA qui partent des HC164: L'idéal serait de pouvoir suivre les circuits visuellement, mais sur cette carte multi-couches c'est très difficile.

Utiliser l'ohmètre pour trouver les liens avec les connecteurs: Pas de chance, aucun lien direct.

Par élimination: On peut ignorer les 2 connecteurs du haut de CON 2: ceux-ci sont reliés aux interrupteurs sous le display.

Ainsi, il ne reste que 2 candidats: en haut du CON1 et en bas du CON2.

Avec un fil, connecter au + l'un des 2 pins. Le Data n'affiche rien. Mais le Clock fait avancer les segments de gauche à droite.

On a maintenant les 2 pins: voir la photo.

Recup ration d un afficheur LED d calage tes-clock-data.jpg

Recup ration d un afficheur LED d calage pins.jpg

Etape n°6 - Connexion à l'Arduino

On peut connecter à l'Arduino, par exemple:

GND -> GND
CON+ -> VCC
CLK -> Pin D3 (PWM)
DATA -> Pin 2

Voici un exemple de code qui permet de contrôler totalement l'affichage.

Et voilà! Plus besoin de commander un nouvel afficheur au bout du monde...

Recup ration d un afficheur LED d calage fini.jpg

Etape n°7 - Le Code

La valeur fournie « 

<span style='color:#004a43; '>#</span><span style='color:#004a43; '>define</span><span style='color:#004a43; '> data 2</span>
	<span style='color:#004a43; '>#</span><span style='color:#004a43; '>define</span><span style='color:#004a43; '> clock 3    </span><span style='color:#696969; '>//D PWM</span>

	<span style='color:#696969; '>/*</span>
	<span style='color:#696969; '> * CHILLER DISP Rev 0.0</span>
	<span style='color:#696969; '>  LED Display:     ___</span>
	<span style='color:#696969; '>                 6! 1 !2</span>
	<span style='color:#696969; '>                  !   !</span>
	<span style='color:#696969; '>                   ---</span>
	<span style='color:#696969; '>                  ! 7 !</span>
	<span style='color:#696969; '>                 5!   !3</span>
	<span style='color:#696969; '>                   ---</span>
	<span style='color:#696969; '>               8°   4         bits: 12345678</span>
	<span style='color:#696969; '>  Connectors:</span>
	<span style='color:#696969; '>                CON3</span>
	<span style='color:#696969; '>            GND GND GND  </span>
	<span style='color:#696969; '>        SW2             DATA</span>
	<span style='color:#696969; '>   CON2 SW1              GND  CON1 </span>
	<span style='color:#696969; '>        CLK              +5V</span>
	<span style='color:#696969; '></span>
	<span style='color:#696969; '> */</span>

	<span style='color:#800000; font-weight:bold; '>unsigned</span> <span style='color:#800000; font-weight:bold; '>int</span> cnt <span style='color:#808030; '>=</span> <span style='color:#008c00; '>0</span><span style='color:#800080; '>;</span>
	byte symbol<span style='color:#808030; '>,</span> symbols<span style='color:#808030; '>[</span><span style='color:#808030; '>]</span> <span style='color:#808030; '>=</span> <span style='color:#800080; '>{</span>
	B11111100<span style='color:#808030; '>,</span> <span style='color:#696969; '>// 0</span>
	B01100000<span style='color:#808030; '>,</span> <span style='color:#696969; '>// 1</span>
	B11011010<span style='color:#808030; '>,</span> <span style='color:#696969; '>// 2</span>
	B11110010<span style='color:#808030; '>,</span> <span style='color:#696969; '>// 3</span>
	B01100110<span style='color:#808030; '>,</span> <span style='color:#696969; '>// 4</span>
	B10110110<span style='color:#808030; '>,</span> <span style='color:#696969; '>// 5</span>
	B10111110<span style='color:#808030; '>,</span> <span style='color:#696969; '>// 6</span>
	B11100000<span style='color:#808030; '>,</span> <span style='color:#696969; '>// 7</span>
	B11111110<span style='color:#808030; '>,</span> <span style='color:#696969; '>// 8</span>
	B11110110<span style='color:#808030; '>,</span> <span style='color:#696969; '>// 9</span>
	B11101110<span style='color:#808030; '>,</span> <span style='color:#696969; '>// A</span>
	B00111110<span style='color:#808030; '>,</span> <span style='color:#696969; '>// B</span>
	B10011100<span style='color:#808030; '>,</span> <span style='color:#696969; '>// C</span>
	B01111010<span style='color:#808030; '>,</span> <span style='color:#696969; '>// D</span>
	B10011110<span style='color:#808030; '>,</span> <span style='color:#696969; '>// E</span>
	B10001110<span style='color:#808030; '>,</span> <span style='color:#696969; '>// F</span>
	B00011100<span style='color:#808030; '>,</span> <span style='color:#696969; '>// L</span>
	B00101010<span style='color:#808030; '>,</span> <span style='color:#696969; '>// M</span>
	B11000110<span style='color:#808030; '>,</span> <span style='color:#696969; '>// °</span>
	B01001010  <span style='color:#696969; '>// %</span>
	<span style='color:#800080; '>}</span><span style='color:#800080; '>;</span>





	<span style='color:#800000; font-weight:bold; '>void</span> setup<span style='color:#808030; '>(</span><span style='color:#808030; '>)</span>
	<span style='color:#800080; '>{</span>
	  pinMode<span style='color:#808030; '>(</span><span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> OUTPUT<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// make the clock pin an output</span>
	  pinMode<span style='color:#808030; '>(</span>data <span style='color:#808030; '>,</span> OUTPUT<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// make the data pin an output</span>
	 <span style='color:#800080; '>}</span>

	<span style='color:#800000; font-weight:bold; '>void</span> loop<span style='color:#808030; '>(</span><span style='color:#808030; '>)</span> <span style='color:#800080; '>{</span>
	  <span style='color:#696969; '>// put your main code here, to run repeatedly:</span>


	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B00000000<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B00000000<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B00000000<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B00000000<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  delay<span style='color:#808030; '>(</span><span style='color:#008c00; '>1000</span><span style='color:#808030; '>)</span><span style='color:#800080; '>;</span>  
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B00000001<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B00000010<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B00000100<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B00001000<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  delay<span style='color:#808030; '>(</span><span style='color:#008c00; '>1000</span><span style='color:#808030; '>)</span><span style='color:#800080; '>;</span>  
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B00010000<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B00100000<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B01000000<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B10000000<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  delay<span style='color:#808030; '>(</span><span style='color:#008c00; '>1000</span><span style='color:#808030; '>)</span><span style='color:#800080; '>;</span>  
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B00000000<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B00000000<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B00000000<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B00000000<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>

	  delay<span style='color:#808030; '>(</span><span style='color:#008c00; '>1000</span><span style='color:#808030; '>)</span><span style='color:#800080; '>;</span>  

	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B10101010<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send this binary value to the shift register</span>
	  delay<span style='color:#808030; '>(</span><span style='color:#008c00; '>1000</span><span style='color:#808030; '>)</span><span style='color:#800080; '>;</span>

	 <span style='color:#800000; font-weight:bold; '>for</span><span style='color:#808030; '>(</span><span style='color:#800000; font-weight:bold; '>int</span> i <span style='color:#808030; '>=</span> <span style='color:#008c00; '>0</span><span style='color:#800080; '>;</span> i <span style='color:#808030; '><</span> <span style='color:#008c00; '>4</span><span style='color:#800080; '>;</span> <span style='color:#808030; '>+</span><span style='color:#808030; '>+</span>i<span style='color:#808030; '>)</span> <span style='color:#696969; '>//for 0 - 7 do</span>
	  <span style='color:#800080; '>{</span>
	    shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B01010101<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// bit shift a logic high (1) value by i</span>
	    delay<span style='color:#808030; '>(</span><span style='color:#008c00; '>500</span><span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// delay 100ms or you would not be able to see it</span>
	  <span style='color:#800080; '>}</span>
	  delay<span style='color:#808030; '>(</span><span style='color:#008c00; '>1000</span><span style='color:#808030; '>)</span><span style='color:#800080; '>;</span>

	 <span style='color:#800000; font-weight:bold; '>for</span><span style='color:#808030; '>(</span><span style='color:#800000; font-weight:bold; '>int</span> i <span style='color:#808030; '>=</span> <span style='color:#008c00; '>0</span><span style='color:#800080; '>;</span> i <span style='color:#808030; '><</span> <span style='color:#008c00; '>4</span><span style='color:#800080; '>;</span> <span style='color:#808030; '>+</span><span style='color:#808030; '>+</span>i<span style='color:#808030; '>)</span> <span style='color:#696969; '>//for 0 - 7 do</span>
	  <span style='color:#800080; '>{</span>
	    shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> B10101010<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// bit shift a logic high (1) value by i</span>
	    delay<span style='color:#808030; '>(</span><span style='color:#008c00; '>500</span><span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// delay 100ms or you would not be able to see it</span>
	  <span style='color:#800080; '>}</span>

	   delay<span style='color:#808030; '>(</span><span style='color:#008c00; '>1500</span><span style='color:#808030; '>)</span><span style='color:#800080; '>;</span>

	 <span style='color:#800000; font-weight:bold; '>for</span><span style='color:#808030; '>(</span><span style='color:#800000; font-weight:bold; '>int</span> i <span style='color:#808030; '>=</span> <span style='color:#008c00; '>0</span><span style='color:#800080; '>;</span> i <span style='color:#808030; '><</span> <span style='color:#008c00; '>12</span><span style='color:#800080; '>;</span> <span style='color:#808030; '>+</span><span style='color:#808030; '>+</span>i<span style='color:#808030; '>)</span> <span style='color:#696969; '>//for 0 - 7 do</span>
	  <span style='color:#800080; '>{</span>
	    shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> MSBFIRST<span style='color:#808030; '>,</span> <span style='color:#008c00; '>1</span> <span style='color:#808030; '><</span><span style='color:#808030; '><</span> i <span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// bit shift a logic high (1) value by i</span>
	    delay<span style='color:#808030; '>(</span><span style='color:#008c00; '>300</span><span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// delay 100ms or you would not be able to see it</span>
	  <span style='color:#800080; '>}</span>

	  delay<span style='color:#808030; '>(</span><span style='color:#008c00; '>1000</span><span style='color:#808030; '>)</span><span style='color:#800080; '>;</span>


	 <span style='color:#800000; font-weight:bold; '>for</span><span style='color:#808030; '>(</span><span style='color:#800000; font-weight:bold; '>int</span> i <span style='color:#808030; '>=</span> <span style='color:#008c00; '>0</span><span style='color:#800080; '>;</span> i <span style='color:#808030; '><</span> <span style='color:#008c00; '>19</span><span style='color:#800080; '>;</span> <span style='color:#808030; '>+</span><span style='color:#808030; '>+</span>i<span style='color:#808030; '>)</span> <span style='color:#696969; '>// counter 0 to F puis -> %</span>
	  <span style='color:#800080; '>{</span>
	  cnt<span style='color:#808030; '>=</span>i<span style='color:#800080; '>;</span>
	  symbol <span style='color:#808030; '>=</span> symbols<span style='color:#808030; '>[</span>cnt<span style='color:#808030; '>+</span><span style='color:#808030; '>+</span><span style='color:#808030; '>%</span><span style='color:#800000; font-weight:bold; '>sizeof</span><span style='color:#808030; '>(</span>symbols<span style='color:#808030; '>)</span><span style='color:#808030; '>]</span> <span style='color:#808030; '></span> <span style='color:#808030; '>(</span>cnt<span style='color:#808030; '>%</span><span style='color:#008c00; '>2</span><span style='color:#808030; '>)</span><span style='color:#800080; '>;</span>
	  shiftOut<span style='color:#808030; '>(</span>data<span style='color:#808030; '>,</span> <span style='color:#603000; '>clock</span><span style='color:#808030; '>,</span> LSBFIRST<span style='color:#808030; '>,</span> symbol<span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// send data</span>
	  delay<span style='color:#808030; '>(</span><span style='color:#008c00; '>500</span><span style='color:#808030; '>)</span><span style='color:#800080; '>;</span> <span style='color:#696969; '>// pause for 1/2 second</span>
	  <span style='color:#800080; '>}</span>


	<span style='color:#800080; '>}</span>

 » contient des marqueurs de bande et ne peut donc pas être suffisamment analysée.

Notes et références