之前四轴飞控DIY集成FPV功能的时候使用RadioLink的遥控器+接收机（2.4GHz）,Due to control distance issues,后来更换TX12 + ExpressLRS 915MHz(RX/TX),The overall effect will be much better,Update and recordRCControl some issues during link configuration,It is convenient for subsequent review and reference.

1. 硬件配置

目前,in remote control+发射机+The configuration aspects of the receiver are as follows：

• 遥控器：TX12
• ExpressLRS 915MHz
  发射机：ESP32 + E32-900M30S + Nano(Lite)接口
  接收机：ESP01F + SX1276
• 天线
  Transmitter Black SheepELRS Dipole天线(T型天线,偶极子天线) 3.3 dBi
  Receiver Black SheepELRS Dipole天线(T型天线,偶极子天线) 3.15 dBi
• 配件：JR(Micro)转接盒

1.1 TX12遥控器

The introduction of the official website is not expanded here,Interested friends can read the link by themselves.Here are a few points to note in the use process.

1. TX12直接USB连上电脑后,can be found automaticallyJoystick.The biggest advantage of this function is that it can directly simulate flight.
   注1：If the device is not found, it may be a generic driver problem,请尝试安装zadig-2.7.
   注2：Some remote controls themselves do not support computer-side simulators or need to purchase special hardware adapters.

2. 支持OpenTx开源软件,At present, the official website production firmware supports it2.3.11版本.
   注1：官网下载链接是Google云盘,Arranged hereCSDN下载（Domestic is more convenient）
   注2：OpenTxOpen source software because it is open source,且目前（近2年）The pace of development is slow（毕竟开源）.

3. 基于OpenTxA case of slow progress in open source firmware development,Introduce one that is currently active and has relatively new functionsEdgeTx开源项目.
   注1：I have now updated to the latest2.7.1版本.
   注2：EdgeTX 2.5 means it’s time to switch away from OpenTX. Here’s how.

1.2 发射/接受机

ExpressLRSIt is also an open source software and hardware project,Comparison test from the Internet:【Happy Model ExpressLRS 900Mhz Hardware - Range Test (Plus crossfire comparison)】看,效果是不错的.

注1：The premise is that the takeoff position is high,Make sure all the wayRCLink headroom;装上GPS,Direct trigger from a long distancefailsafe返回Home.

For the time being, the internal losses of the hardware system are not considered,默认ELRS 915MHz 200Hz Packet Rate情况下（接受灵敏度-112dBm）,采用默认的LKM 12dB,About theoretically有54.77km.

注2：Need to pay attention to the hardware we purchasedRFtransmitter moduleE32-900M30SNominal is10KM,So the actual distance is not necessarily as onlineHappy Model ExpressLRS那么好.

2. 问题汇总

2.1 ELRSThe receiver fails to light up

Been using it for a while,The receiver was inexplicably unable to light up.目前了解到的信息显示：s.port没信号,Positive and negative voltage,The transmitter will turn on（不发射信号）,RGBOrange light breathing state,1It turns green after a few minuteswifi状态.

1. 【7.56V】测试遥控器JR(Micro)Interface voltage output
2. 【7.68V】测试JR(Micro)transfer boxNano(Lite)Interface voltage output
3. 【Does not light up properly】重新插拔 JR(Micro)转接盒 和 ELRS Nano(Lite)模块

After the above simple test（判断电压6-12V条件）后,送修.

维修情况：

1. 【正常】直接给ELRS Nano模块供电
   2. 【正常】JR(Micro)The power supply end of the transfer box is directly connected with three wires inside
   The final repair positioning problem：MicroThere is a problem with the socket（经讨论,Do not rule out the remote control power supply part of the problem）.

注：疑问：实际测量GND/VCC在Micro/LiteThere are voltage outputs on the interface,Why doesn't it light up（屏幕,LED）？Does this lit action dependS.Port上的命令？

2.2 触发EdgeTX固件更新

当前最新的版本是V2.7.1,See update steps for details链接.

Update the previous versionOpenTx V2.3.1

The version after the upgrade is complete EdgeTx 2.7.1

The main reason is that the following sentence is not understood, so it has been unable to update.

5. Boot your radio in bootloader mode (holding trim switches T4 and T1 to center while pushing the power button on).

第五步：when starting the remote control,T4和T1Colleagues holding inward,按电源键启动,进入bootloader模式.

2.3 elrsV2.lua脚本执行失败

从ELRS git主线Download the mainline versionelrsV2.lua版本,执行失败,如下图所示.

这里存在两个问题：

1. 右键“另存为”的时候,There are a large number of saved fileshtml符号,导致lua脚本无法执行;
2. gitThere are issues with the mainline version itself,无法执行,The official release should be usedtag或者分支（确保lua脚本可执行）;

2.4 ELRSHow the transmitter and receiver are aligned

The frequency binding method：

1. to the receiver3secondary power up(通-断、通-断、通)Enter the binding state,LEDwill keep flashing twice quickly,Waiting for binding;
2. Remote control passeslua脚本进入BIND选项(Or operate the button on the transmitter to enterOLED显示BIND菜单),点击确认后,Wait for the receiverLEDAfter it turns to steady light, the frequency binding operation can be completed

2.5 ELRS接收机LED状态识别

• 慢闪烁：Waiting for a connection from the transmitter(The frequency has been linked or the binding code has been set)
• 快速闪烁：进入WIFI模式(After the receiver is powered on60The transmitter is not connected or not bound after seconds,则进入WIFI模式)
• Flashes twice：Wait for the frequency binding status(The frequency is not connected or the binding code is not set)
• Three flashes：A transmitter is connected but the parameters do not match(固件不匹配)
• 常亮：The normal state of the connected transmitter,或进入BOOT模式(If not entered by humans,It is connected to the flight controller when it is powered onUARTThe port is abnormal)

2.6 Differences between receivers and open source code

915M请选择DIY_900_RX_ESP8285_SX127X

注:2022.7.15日之前购买的915The receiver needs to modify the source code5脚定义,After purchase, you can directly brush online without modification