PixelRadio, a DiY FM Transmitter with RDS RadioText

**Glycerine** · 05-10-2022, 10:41 AM

Speaking of soldering, if anyone is looking for more projects, I've built several of these: https://www.instructables.com/DIY-Di...ering-Station/

They are a pretty easy build. I made a few modifications to mine, such as extending the case a bit and adding a momentary push button (and code changes) to allow for saving/loading a preset temperature.

**dirknerkle** · 05-10-2022, 01:32 PM

Originally Posted by Glycerine

Speaking of soldering, if anyone is looking for more projects, I've built several of these: https://www.instructables.com/DIY-Di...ering-Station/

They are a pretty easy build. I made a few modifications to mine, such as extending the case a bit and adding a momentary push button (and code changes) to allow for saving/loading a preset temperature.

You built "several" of them? Why is that? Didn't they work very long or well?

**Glycerine** · 05-10-2022, 02:58 PM

Originally Posted by dirknerkle

You built "several" of them? Why is that? Didn't they work very long or well?

Mostly for fun and just to have extras, since they are fairly cheap to make. Sometimes my kids like to solder, so it's good to have several of them around.

So far, they have worked very well.

If you build one though, you do have to make sure to use a specific heating element. Some of the "clones" will work and others won't. The resistance values of the filament/sensor need to match the Hakko A1321 heating element. I bought some clones that were advertised as A1321, but they appear to actually be A1322. Which is fine because those will work with my Yihua soldering station...

**sonic777** · 05-10-2022, 09:51 PM

Hey Thomas, I was reviewing your code and referencing your board, it looks like you left a lot of meat on the table for those of us who like to tinker. I appreciate that and want to thank you for bringing this project to everyone's attention.

As I was reviewing the board, it got me to thinking about some idea's about some past projects I shelved since I was using 8266 boards at the time. I noticed that you have a J2 marked with I2S and what traces to J3 (jumper maybe?) as well as GPIO EXP-01 J1 & GPIO EXP-2 J4. Then there is the J7 I2C pinout.

I was wondering if these were all really available for expansion or are these test traces?

If they are available, I have a couple of other questions I hope you don't mind me asking.

1. On J1 (GPIO EXP-1) it's clearly marked. Are the identified pins 19, 23, and 33 the matched values for the GPIO's?
2. On J4 (GPIO EXP-2) it's not clearly marked. Would you be able to identify these or are they in the documentation?
3. Is J3 a jumper for J2 or something else?
4. Is J7 the I2C for the FMV (I don't know if the FMV has an I2C) or the ESP32? Or is this just a test pinout for the two I2C connections?

These questions maybe simple for some, but I don't design electronics, just tinker in the space.

**ThomasLED** · 05-11-2022, 12:51 AM

1. On J1 (GPIO EXP-1) it's clearly marked. Are the identified pins 19, 23, and 33 the matched values for the GPIO's?

That is correct. Those three GPIO's are supported by PixelRadio's controllers. It is explained here:
https://github.com/thomastech/PixelR...ual/GpioTab.md
The commands for controlling the GPIO pins are found here:
https://github.com/thomastech/PixelR...mmand-keywords

2. On J4 (GPIO EXP-2) it's not clearly marked. Would you be able to identify these or are they in the documentation?

Two GPIO pins on this port can be enabled for use as GPIO (3.3V TTL) serial. The Optional GPIO Serial feature is explained here:
https://github.com/thomastech/PixelR...ial-controller

3. Is J3 a jumper for J2 or something else?

J3 must NOT be installed on production boards. It was used during development to power the 5V devices from USB power (L7805 not installed).
J2 is available for those that want to integrate an I2S audio device for streaming music to PixelRadio (wireless audio connectivity). I don't have plans to develop this, but maybe someone will do it.

4. Is J7 the I2C for the FMV (I don't know if the FMV has an I2C) or the ESP32? Or is this just a test pinout for the two I2C connections?

J7 is available to control other I2C devices a user might want to add.

Of course all these unused headers are available for other devs to add more features to PixelRadio. The ESP32's generous flash memory size has extra code space to do more amazing things. So feel free to add features and/or make improvements.

- Thomas

**ThomasLED** · 05-12-2022, 03:48 PM

Has anyone had a chance to test out their PixelRadio? That is to say, place it at the intended operating location, connect up the music source, then drive by while listening to your car's RDS radio. Would be great to hear some feedback, so hopefully one of the project builders reports on this soon.

BTW, PixelRadio passed a month long stability test. It did not experience any random reboots due to software and/or hardware problems.

Test Setup:
1. The FM's RF output port was terminated with a dummy load. This allows the transmitter to operate without broadcasting an RF signal.
2. The Test Tone function was enabled. It provided the audio signal and RDS text messages.
3. PixelRadio's Diagnostic page has a System Run Time display. It is initialized to zero at startup. This is used to detect reboots.

About halfway through the test my six year old WiFi router died. Thanks to Amazon a new one quickly arrived and was installed. PixelRadio gracefully reconnected. I noticed that a couple of my home automation ESP32/ESP8266 based devices weren't happy about this event (they rebooted).

This was not a stress test. But it was still nice to see that PixelRadio remained stable for the 30 day test period. See screenshot below.

- Thomas

**rayhjr** · 05-12-2022, 10:14 PM

I hope to test this weekend.
Even though my 2001 F-150 (335,000 miles) and the Wife's 2004 Blazer (185,000 miles) have aftermarket Radios in them, neither have RDS, LOL. I Really thought the wife's Blazer had RDS.
The Daughter is coming Saturday with her new Truck and we can see then, I hope. We have been busy planning my wife a Surprise Birthday Party this Saturday and working 12 hr. days.

**ThomasLED** · 05-13-2022, 01:06 PM

The Daughter is coming Saturday with her new Truck and we can see then, I hope.

Great, hopefully you can check out your PixelRadio on the new truck. A late model vehicle (~2010 or newer) will typically have a big infotainment screen, which is ideal for the RDS RadioText messages. Older RDS radios usually have small displays with limited character space, so the messages will be less joyful to view.

- Thomas

**Keith R** · 05-17-2022, 05:19 PM

OK, I'll be honest. I really had a difficult time with this and there are a couple of posts that helped alot. Read everything and be patient. I am not good at first time stuff, but I think I am headed in the right direction. This is only the ESP32 board. Please let me know if I am missing anything. Thanks

**ThomasLED** · 05-17-2022, 07:01 PM

This is only the ESP32 board. Please let me know if I am missing anything.

Screenshot looks correct.

1. Hardware fails because the FM radio transmitter is missing.

2. AP mode is for initial setup. So now is a good time to visit PixelRadio's WiFi tab and submit your router WiFi credentials. That will enable STA mode, which is required for normal operation.

- Thomas