This tutorial describes how to use the open source FPVSIM Timer Configurator to flash firmware for the ESP32 timing unit. Download the corresponding installation package according to the operating system, connect the USB data port of the timer, select the firmware version, target hardware and serial port in the tool, and then execute Build & Flash; the first run will additionally download the flash tool, so it is usually slower than subsequent flashes.
Choose the correct Configurator installer
FPVSIM Timer Configurator is based on the ExpressLRS Configurator flashing workflow, so its interface and operation will be familiar to ExpressLRS users. At the time of recording, GitHub Releases provided a Debian package for Linux, an EXE for Windows, and a DMG for macOS. Today, visit the official release page and choose the current version and an asset matching your system architecture.
Install only trusted official release files. If the operating system displays a security warning, first verify the download source and signature. Do not bypass security policies on a company or event computer just to save time. The old video showing only one release or target does not mean future versions will have only one option.
Connect the hardware and run Build & Flash
Connect the ESP32 timing unit to the computer using a USB data cable. Open Configurator, select the intended firmware version and hardware target, then choose the newly appeared ESP32 port from the serial-port list. If you are unsure, unplug the device to see which port disappears, then reconnect it to confirm.
After clicking Build & Flash, keep the USB connection and power stable. Do not unplug the cable, put the computer to sleep, or close the app during writing. The first flash needs to download underlying tools and build resources, so a longer wait is normal. Subsequent flashes are usually faster once these resources are cached. Proceed to the next setup step only when the tool explicitly reports completion.
Checks after flashing
Successfully writing the firmware does not mean the entire timer is configured. Power-cycle it and confirm that it starts correctly and broadcasts its hotspot, then follow the networking guide for that version to configure the router, channel, and timing parameters. If flashing fails, save the complete log first and check the data cable, serial-port use by other programs, drivers, and target rather than repeatedly retrying blindly.
The open-source tools and firmware continue to change. If an option differs from the video, follow the current Releases notes and in-app prompts. Record the flashed version so you can keep multiple timers consistent or roll back if a problem appears.
Operation steps
- Open the official release page
Find the current FPVSIM Timer Configurator release and verify the download source.
- Choose the installer for your operating system
For Linux, Windows, or macOS, download the matching Debian package, EXE, DMG, or the format listed on the current release page.
- Select the release, target, and serial port
After connecting the ESP32, confirm the firmware version, hardware target, and newly appeared device port.
- Run Build & Flash
Start the build and flash process and keep the connection stable. The first run needs to download tools and may take longer.
- Confirm completion before configuring the timer
After a successful result, power-cycle the timer, verify its hotspot and startup status, then proceed to network and timing settings.
FAQ
Why is the first flash much slower?
Configurator usually needs to download flashing tools or related resources on first use. Later operations are often faster once these are cached.
What if I do not know which serial port to select?
Disconnect the ESP32 to see which port disappears, then reconnect it to confirm. Also ensure that the USB cable supports data transfer rather than charging only.
Why do the release and target in the video differ from the current options?
The video shows the version available at the time. Firmware and tools change; follow the current official Releases page and the options in Configurator.
Can I start racing immediately after a successful flash?
Do not assume setup is finished. You still need to verify startup, the hotspot, networking, the channel, and actual timing, and ensure that multiple devices use compatible versions.
Full timeline transcript
Transcripts are arranged according to video time, making it easy to quickly locate the explanation content. Transcript language: Simplified Chinese.
Hello everyone, this is QuadRank. It has been a while since I last came out to chat with you. Recently, many people have been asking about the timer, so I will be putting out some updates about it. Where should we start? Let us start with the flashing tool. When I released the first timer design, we used the official ESP32 downloader. To be honest, that downloader was very awkward to use. You had to fill in a lot of things, right? A lot of fields here. Is there a better way?
We now have a better tool: FPVSIM Timer Configurator. This flashing tool is based on the ExpressLRS flashing tool. If you are familiar with that, this one will be easy to use too. How do we use it? Open the releases section and find the download.
I am using Linux, so I will download the Debian package directly. For Windows, it is the EXE; for Mac, it is the DMG. I will download it first. OK, the download is finished. Then install it. Different operating systems have different installation procedures, so I will skip that here. After installation, you will see Configurator. Open it. OK, you can see that this interface looks very similar to ELRS.
Here you can select the release. There is only this release at the moment, but there may be new releases by the time you watch this video. There is also only one target, so select it. After selecting it, connect the timer to the computer using a USB cable. OK, it is connected. Here you can see the ESP32 serial port. Select it, then click Build & Flash. It starts downloading the flashing tool. The first time—
—you flash it, the flashing tools need to be downloaded, so it takes longer. Later flashes will be faster. In my case, I have already downloaded the flashing tools once, so this is very fast. It writes the firmware into the ESP32. OK, flashing is now complete. How do we configure it after flashing? We will continue in the next video. Thank you for watching.
