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--- documentation:electronique:infrared:index [2022/09/05 18:11] – ↷ Liens modifiés en raison d'un déplacement. f1sls
+++ documentation:electronique:infrared:index [2022/09/05 18:21] (Version actuelle) – f1sls
@@ Ligne 1: / Ligne 1: @@
+{{:index_01.png?64|}}
+<catlist -forceHeadTitle -exclupage -sortAscending -hideNotFoundMsg -columns:1 -maxDepth:1 -noHead -noAddPageButton -ACLhideNs>
+----
 ====== INFRARED [COLLAGE] ======
@@ Ligne 8: / Ligne 13: @@
   * {{ documentation:electronique:infrared:hsdl1001_datasheet.pdf |Datasheet}}
 {{documentation:electronique:infrared:hsdl1001_pinout_wiring_01.gif|}}
+====== FAR IR / NEAR IR ======
+<blockquote>Its probably worth saying that there are two sorts of IR detector, "far IR" is used for passive heat
+sensing and thermal imaging - this has a wavelength range of about 6 to 10 µm, and is not detected
+at all my photodiodes or phototransistors. At these wavelengths glass absorbs, so any lenses have to
+be made of exotic materials and are expensive. No source of illumination is needed, the heat of objects
+is enough to radiate.
+"near IR" is close to the visible range of light, say 0.7 to 1.5µm (700 to 1500nm) range, and most
+photo diodes and photo transistors have peak sensitivity in this range, typically 780 or 850nm. Such
+near IR behaves like light and can go through glass lenses (for instance). For seeing at night in near
+IR you need a source of (near IR) illumination. Most visible light sources also put out near IR, so
+a white flame will, but a blue flame probably gives out nothing in near IR, but loads and loads in
+far IR.</blockquote>

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