finish post (closes #12)

2025-12-11 17:30:40 -06:00
parent f1e8ff5702
commit 97be183c59
1 changed files with 36 additions and 8 deletions
@@ -1,7 +1,7 @@
 +++
 categories = ["build"]
 tags = ["bicycle"]
-date = 2025-08-07T08:00:00-05:00
+date = 2025-08-12T12:15:00-05:00
 description = ""
 draft = false
 slug = "bicycle-headlamp"
@@ -14,7 +14,7 @@ Nighttime bicycle rides in the summer are ideal:
 - 🚘 little traffic
 - 🦝 nocturnal wildlife 

-But it is not easy to see in the dark, so I bring a headlamp and okay, fine, this works. With my current head lamp I can see and be seen just fine. But there are some limitations. I see wonderfully directly ahead of me in the narrow cone of light provided, but at the edges of this light cone I see practically nothing at all, as though I am looking through a paper towel roll. The beam pattern is optimized for riding in a straight line, with little regard for what lies in the periphery. **I would like a greater field of view, so I will need a lamp with a wide beam pattern.**
+But it is not easy to see in the dark, so I bring a headlamp and *okay, fine, this works*. With my current headlamp I can see and be seen just fine. But there are some limitations. I see wonderfully directly ahead of me in the narrow cone of light provided, but at the edges of this light cone I see practically nothing at all, as though I am looking through a paper towel roll. The beam pattern is optimized for riding in a straight line, with little regard for what lies in the periphery. **I would like a greater field of view, so I will need a lamp with a wide beam pattern.**

 ## 🔦 Headlamp
 I start by selecting the headlamp. This is the most important component, and everything will revolve around it. My selection criteria is simple. The light must have these features:
@@ -36,11 +36,19 @@ I had to settle for the **OPL5 Motorcycle LED Headlamp**:
 | Brightness | 3000 lm |
 | Color Temperature | 6500K (Cool White) |

-✅ **This will have to do**.


 {{< image src="images/opl5-motorcycle-led-headlamp.png" >}}

+
+{{< image 
+    src="images/beam-pattern.JPG"
+    caption="OPL5 Beam against the wall" >}}
+
+Notice the sharp beam cutoff at the top. This is what allows me to have a very bright headlamp while also not blinding oncoming traffic. Also, the beam gradient at the bottom transitions from very bright to very dim, in a manner that maximizes usable light. It concentrates maximum light near the upper cutoff where it will disperse across a large surface area at long distances, while minimizing output in the near and mid field, where the illuminated surface area should be relatively small.
+
+✅ **This will do**.
+
 ---

 ## 🧰 Case
@@ -62,7 +70,7 @@ Since the headlamp consumes 48 W, I need a battery that can sustain this load fo

 - $t$ = run time (hr)
 - $E_\text{battery}$ = battery energy (Wh)
- $p_\text{load}$ = LED headlamp power (W)
+- $P_\text{load}$ = LED headlamp power (W)

 $$
 t = \frac{12.8 \text{ V} \cdot 16 \text{ Ah}}{48 \text{ W}} = 4.27 \text{ hr}
@@ -113,6 +121,10 @@ Now for final assembly. This is all very simple and I ran into no issues.
 - Sealed the power port and switch mounting holes with silicone
 - Removed the battery enclosure lid since the battery terminals were ≈ 1 mm proud of the battery box lid. The battery box would still close, but it was straining the plastic and the weather sealing would be compromised.

+{{< image 
+    src="images/battery-box-open.JPG"
+    caption="Battery box inside" >}}
+
 Here is a **wiring diagram** of the circuit.

 {{< image src="images/bicycle-headlamp-wiring-diagram.svg" >}}
@@ -124,16 +136,32 @@ Here is a **wiring diagram** of the circuit.
 | SW1 | SPST Switch |
 | LED1 | 48 W |

-I strap the battery box to the rear cargo rack with hook and loop straps. 

-That is all.
+{{< image 
+    src="images/battery-box-power-port.JPG"
+    caption="Battery box power port" >}}

--
+{{< image 
+    src="images/battery-box-switch.JPG"
+    caption="Battery box switch" >}}    
+
+{{< image 
+    src="images/battery-box-mounted.JPG"
+    caption="Battery box fastened to the rear cargo rack with hook and loop straps" >}}
+
+{{< image 
+    src="images/headlamp-mounted.JPG"
+    caption="Headlamp on handlebars" >}}
+
+
+---

 ## 🚴 Test Drive 
 All that remains is the test drive.

-{{< image src="images/headlamp-night-test-drive.jpg" >}}
+{{< image 
+    src="images/headlamp-night-test-drive.jpg"
+    caption="Wide beam width" >}}

 🎉 **It works!**