MAKER: Ekul92／译：趣无尽（转载请注明出处）

圣诞节马上就要临近了，大家有没有开始装扮圣诞树呢！本期给大家带来一个用 NeoPixel 库点亮圣诞树的项目。项目非常的简单，即使你没有任何基础，也可以跟着教程搭建！

一棵盛装打扮的圣诞树绝对是节日的氛围担当！绿树银花，一杯热咖啡，在麋鹿和圣诞树的陪伴下，我们可以倒数着新年的钟声！愿所有美好如期而至，愿所有幸运不期而遇。

组件清单

树莓派 Zero V2 x 1
NeoPixel LED 灯条（5×50 规格） x 5
5v PSU x 1
绝缘胶带 x 1
电线盒 x 1

配置树莓派

配置树莓派、安装 Node-RED 和其他软件包。

常规安装树莓派系统，参考教程：
https://shumeipai.nxez.com/2013/09/07/how-to-install-and-activate-raspberry-pi.html

2、运行以下命令安装 Node-RED

bash <(curl -sL https://raw.githubusercontent.com/node-red/linux-installers/master/deb/update-nodejs-and-nodered)

将 Node-RED 设置为启动时自动启动

sudo systemctl enable nodered.service

3、运行以下命令安装 Unicorn HAT 驱动：
https://learn.pimoroni.com/article/getting-started-with-unicorn-hat

该驱动将实现树莓派与 NeoPixels 库的连接。

curl -sS get.pimoroni.com/unicornhat | bash

安装 Unicorn HAT 后，它将会更改音频的设置并重启。

注意：如果上述命令因为权限而无法运行，请在命令前面添加“sudo”并在出现提示时输入密码。

设置 Node-RED

当树莓派配置好后，再设置 Node-RED 服务器。在树莓派上安装 http://localhost:1880 或在本地网络的计算机上搜索服务器。在另一台机器上浏览时请使用主机名或 IP 地址设置为 http://hostname:1880。你可以通过在树莓派上运行 “hostname -I”来找到 IP 地址。

我们需要添加两个模块，让 LED 灯点亮起来，我将提供三种添加的方式。
1、点击以下链接添加模块：
node-red-dashboard
https://flows.nodered.org/node/node-red-dashboard
node-red-node-pi-neopixel
https://flows.nodered.org/node/node-red-node-pi-neopixel

2、如果你更喜欢通过命令行添加模块，可按照链接查找命令，并确保位于正确的目录中，以便 Node-RED 可以找到它们。

3、通过导航到网页上的 UI 添加模块
单击右上角的“Menu”按钮 -> 选择“Manage palett” -> 选择“Install” -> 在搜索字段中输入“node-red-dashboard”-> 在最上面的选项上选择“install” -> 完成后，输入“node-red-node-pi-neopixel”-> 在唯一可用选项上选择“install”-> 最后，选择“Close”。

目前，Node-RED 已经拥有了运行 LED 和用户界面所需的所有模块。现在可以添加定义使用、树莓派和 LED 灯的输入和输出。

单击右上角的“Menu”按钮，选择“Import”，然后将以下内容粘贴到打开的对话框中：

[{"id":"85fce9c6579baaa0","type":"tab","label":"Christmas Lights Simple","disabled":false,"info":"","env":[]},{"id":"cc28a93a30fc342a","type":"ui_colour_picker","z":"85fce9c6579baaa0","name":"Color Picker","label":"COLOR PICKER","group":"d2ace9cc.9f3998","format":"rgb","outformat":"string","showSwatch":true,"showPicker":true,"showValue":true,"showHue":false,"showAlpha":false,"showLightness":true,"square":"false","order":1,"width":0,"height":0,"passthru":true,"topic":"","x":370,"y":360,"wires":[["024561a721d6f79c"]]},{"id":"024561a721d6f79c","type":"function","z":"85fce9c6579baaa0","name":"Set Color","func":"var count = global.get('count')||0;\nmsg.payload = msg.payload.replace(/[rgb()\\s]/g,\"\");\nif(count===0){\n    msg.payload = msg.payload;\n}\nelse{\n    msg.payload = (count-1) + \",\" + msg.payload;\n}\n\nreturn msg;","outputs":1,"noerr":0,"x":540,"y":360,"wires":[["c0297b03d780b3ae"]]},{"id":"693df877b38a2cf1","type":"ui_button","z":"85fce9c6579baaa0","name":"Clear","group":"d2ace9cc.9f3998","order":6,"width":0,"height":0,"passthru":false,"label":"CLEAR","tooltip":"","color":"","bgcolor":"","icon":"","payload":"0,0,0","payloadType":"str","topic":"","x":190,"y":460,"wires":[["a96f4433de81777e","663a12cf6cede0ef"]]},{"id":"206d8115b7db9943","type":"ui_dropdown","z":"85fce9c6579baaa0","name":"Select Strip Color","label":"SELECT STRIP COLOR","tooltip":"","place":"SELECT STRIP COLOR","group":"d2ace9cc.9f3998","order":4,"width":0,"height":0,"passthru":true,"multiple":false,"options":[{"label":"RED","value":"255,0,0","type":"str"},{"label":"GREEN","value":"0,255,0","type":"str"},{"label":"BLUE","value":"0,0,255","type":"str"},{"label":"WHITE","value":"255,255,255","type":"str"},{"label":"PURPLE","value":"255,0,255","type":"str"},{"label":"CYAN","value":"0,255,255","type":"str"},{"label":"YELLOW","value":"255,255,0","type":"str"}],"payload":"","topic":"","topicType":"str","className":"","x":370,"y":420,"wires":[["c0297b03d780b3ae"]]},{"id":"9d8f5d23eeba3096","type":"delay","z":"85fce9c6579baaa0","name":"","pauseType":"rate","timeout":"1","timeoutUnits":"seconds","rate":"4","nbRateUnits":"0.0101","rateUnits":"second","randomFirst":"1","randomLast":"5","randomUnits":"seconds","drop":false,"outputs":1,"x":710,"y":560,"wires":[["c0297b03d780b3ae"]]},{"id":"c0297b03d780b3ae","type":"rpi-neopixels","z":"85fce9c6579baaa0","name":"WS2812B LED STRIP","pixels":"250","bgnd":"","fgnd":"","wipe":"0","mode":"pixels","rgb":"grb","brightness":"40","gamma":true,"x":960,"y":400,"wires":[]},{"id":"40080ab07f9975a1","type":"ui_button","z":"85fce9c6579baaa0","name":"Christmas","group":"d2ace9cc.9f3998","order":5,"width":0,"height":0,"passthru":true,"label":"Christmas","tooltip":"","color":"","bgcolor":"","icon":"","payload":"true","payloadType":"bool","topic":"","x":200,"y":620,"wires":[["5db1f6bc1f363b40"]]},{"id":"34273e36c70ad99f","type":"debug","z":"85fce9c6579baaa0","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"reset","targetType":"msg","x":750,"y":700,"wires":[]},{"id":"5db1f6bc1f363b40","type":"function","z":"85fce9c6579baaa0","name":"Christmas","func":"var numberOfLEDs = 250;\n\nvar j = 0\n\nwhile (j<numberOfLEDs+1){\n        var setColor = j+','+ 255 +','+ 0 +','+ 0;\n        node.send({payload:setColor});\n        j++;\n        var setColor = j+','+ 0 +','+ 255 +','+ 0;\n        node.send({payload:setColor});\n        j++;\n        var setColor = j+','+ 0 +','+ 0 +','+ 255;\n        node.send({payload:setColor});\n        j++;\n}","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":460,"y":620,"wires":[["c0297b03d780b3ae"]]},{"id":"a96f4433de81777e","type":"change","z":"85fce9c6579baaa0","name":"","rules":[{"t":"set","p":"reset","pt":"msg","to":"payload","tot":"msg"},{"t":"delete","p":"payload","pt":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":440,"y":520,"wires":[["9d8f5d23eeba3096","34273e36c70ad99f"]]},{"id":"663a12cf6cede0ef","type":"delay","z":"85fce9c6579baaa0","name":"","pauseType":"delay","timeout":"1","timeoutUnits":"milliseconds","rate":"1","nbRateUnits":"1","rateUnits":"second","randomFirst":"1","randomLast":"5","randomUnits":"seconds","drop":false,"outputs":1,"x":530,"y":480,"wires":[["c0297b03d780b3ae"]]},{"id":"d2ace9cc.9f3998","type":"ui_group","name":"Christmas tree","tab":"14b7bf29.77ead1","order":1,"disp":true,"width":"6","collapse":false},{"id":"14b7bf29.77ead1","type":"ui_tab","name":"Lights","icon":"dashboard","order":1,"disabled":false,"hidden":false}]

选择“Import”后，你可以看到如图所示的流程。选择右上角的“Deploy”，打开一个新选项并导航到 UI 为“ http://hostname:1880/ui”（将 hostname 替换为树莓派的 IP 地址），完成后可以看到用户界面的图像。

注意：此代码 LED 灯光的强度设置为 40%，这样可以减少 PSU 的功率消耗，LED 灯的亮度也不错。如果你想调整亮度，只需双击流程最后的 “rpi-neopixels node”，进行调整即可。

布线

布线前请确保关闭树莓派。布线到树莓派非常的简单，请点击链接查看。
https://tutorials-raspberrypi.com/connect-control-raspberry-pi-ws2812-rgb-led-strips/

只需要连接地线和 LED 的线即可，请确保连连线正确。

LED 灯条的连接方式如下：
Vin-红色
Ground-白色-树莓派引脚 6
Signal-绿色-树莓派引脚 12 (GPIO 18)

因为音频在 GPIO 上使用相同的引脚，所以音频在树莓派上为 HDMI。连接到树莓派后，可以将 PSU 连接到 LED 灯条。你可以根据自己的喜好选择 LED 灯的数量和长度，然后连接到 PSU，最后将 PSU 隐藏在圣诞树的后面。

请确保所有裸露的电线用绝缘胶带包裹好，并将电线放入电线盒中，防止小孩触电。

完成所有接线后，就可以为树莓派和 LED 灯供电。树莓派启动后，从你选择的设备导航到 http://hostname:1880/ui （可将 hostname 替换为树莓派的 IP 地址）。同时可以将 UI 的快捷方式保存到手机上，这样就可以随时访问。

按下按钮，圣诞树就会点亮啦！好心情是不是随之而来呢！

via