A simple home brew FM ham radio repeater.
To make the experience fit your profile, pick a username and tell us what interests you.
JPEG Image - 2.22 MB - 09/21/2020 at 21:20
JPEG Image - 2.41 MB - 09/21/2020 at 21:20
I just finished modifying the board design to put the ESP32 directly in the audio pathway between both SA818 modules. This way it has full control of what is transmitter over the repeater. (This also means it can cut off someone without just unkeying the output.)
Below are pictures of the new design. The resistors and caps on the back will allow for experimenting with how to get the audio into the ESP32. The caps are coupling caps. (Which I may end up just bridging) and the resistors are to possibly add a DC Bias if needed, and this is on the input and outputs from the ESP32. This design also allows for directly running this repeater as an M17 Analog Gateway as well without any design changes. (In theroy)
Recently I started working on this project more again after not touching it for a while. I am working on re-working the PCB again to provide proper connections for the ESP to the audio lines from and to both SA818 modules. This will allow for streaming audio in and out of the repeater along with even voice announcements. (Or implementing an M17 Client for attaching the repeater to a module on an M17 Reflector.)
I have to do some more experimenting to figure out how to properly connect the ESP audio lines as I don't want to have to re-spin the board over and over. (Its cheap but not super cheap.)
All in all I am closer then I have been in a while. I hope to have it done before Hamvention this year (May 20-22) so I can bring it with me and show it off some.
I haven't been able to make much progress on the board recently. Mostly due to getting annoyed with the programming not working as I expect. (The interrupts for example.) And also waiting for parts to even try building the next version of the board. (I ordered the radio modules about 2 weeks before Christmas and they still haven't arrived.)
There is also going to be the delay it takes to spin the new board once I pull the trigger and do so. But before I can do that I have to finish laying out the power delivery part of the board to allow for using a supply thats not 3.3 volts. I also have to add some decoupling caps to the power supply lines on both radio modules and the ESP32 as sometimes the radios can brown out the ESP32 with my current power supply I am using.
I just finished re-working the boards schematic and pcb layout.
Here is the final product.
It will fit inside an altoid's tin. It requires 3.3 volts to run still. I think I might make a slight modification to add voltage regulation and also I still need to get the interrupt's working on the board I have before I decide to do a spin of this board. (As it might be a missing pull up or something.)
I have been able to get it functioning properly today.
I had to do some more flying wires. Turns out I really messed up this first board. I guess that is why all good projects have multiple versions. It will do a simple repeater of what comes in the input radio to the output module's freq. For now I have been using one of the 70cm Unprotected Shared Pairs.
It is currently just making the PTT on the TX Radio follow the Audio On signal of the RX Radio. Originally I wanted to use an Interrupt to do this on the rising and falling edge but for some reason the interrupt refuses to fire. I am not totally sure why that is either.
It currently has no way to timeout or identify itself. (I was happy enough to even getting it repeating for now.) Next set it to try and make it ident at all then I will work on the timeout features.
Once I get all that working is when I will start looking into making a web page to allow you to configure it over the network.
i have managed to get the board programming. Now i just have to work out what issues i have in my firmware.
While trying to program the ESP32 I found a few big mistakes in my PCB. Firstly I forgot to route the Enable Pin. thankfully I can easily solder a wire to it. I also made another mistake with Pin 2. During programming Pin 2 has to be held low or floating. I had it pulled high and used as the PTT for the Input radio. Thankfully this is an easy fix on the current board of just cutting its trace.
I haven't found any additional issues and will be trying to get it working over the course of the week.
I have had this sitting on my USB for a while and just forgot to push it to github. https://github.com/wgaylord/ESP32-Repeater-Controller
It firsts initializes all the needed pins then both radio modules before registering two interrupt routines.
The interrupt routines are used for detecting when the RX radio gets a signal to trigger the TX radio.
The main loop does a check if its been on for too long. (Someone talking a long time with out unkeying) If this is the case it turns of the TX modules PTT. The next thing it does is the Identification. I will probably have to add some sort of delay to this but I will figure that out when I have to.
I will be trying to program the module over the next week.
I finally assembled the board.
I will be trying to program it over the next few weeks.
I am posting this as an update of whats going on.
I am going to attempt to assemble the PCBs this week end and hopefully program it shortly after. I also realized that I currently don't have a good enough 3.3v supply to actually run/program the repeater board once assembled. So I guess its time to design up a power supply board that can power the repeater and also the future Power Amplifier board.
I have also yet to fix the resistor issue on EasyEDA because I haven't assembled the PCB to know if it will actually be an issue or not.
Become a member to follow this project and never miss any updates