I have been a follower of Xose Perez Espurna since long now. He is doing a fascinating job developing that firmware and the community has grown and thrived. Very inspiring indeed.
When I found Espurna I was brand new to the NodeMCU idea and the internet of things. But slowly I have gotten in to it. And today I managed to get Xose’s firmware to spark on an ESP-01s together with “Relay shield v1.0” that I modded so that the ESP-01s could autoboot when mounted on it. This is to my knowledge the cheapest and maybe also the smallest platform for running Espurna.
I got mine from Aliexpress for 21:72 SEK ( USD 2:70 ) including shipping to Sweden.
To get Espurna firmware in ESP-01s I used a programming adapter also from Aliexpress. This was the one I used. It was not a big deal, but you have to modify the GPIO settings for LED, Realy pin and button to remap those before you build and burn the firmware into the ESP-01s. I did this in the espurna/code/espurna/config/hardware.h file.
When I was done with flashing the firmware and attached the ESP-01s into the Relay shield the dissapointment was big… It didn’t boot. But after a while I understood that a lot of pins on ESP-01s have to be in certain states to get the device to boot from flash, and the relay shield did not fix that to my surprise.
So I modified the “Relay shield v1.0” like this…
* I connect the CH_PD pin to RST pin. It is the two lower pins in the middle of the connector in the picture below. I used a small piece from a component leg to bridge the two solder points. But maybe just a glob of tin will do.
* Connect a 10K Ohm resistor as a pull up to the GPIO0 pin. I did that by soldering a SMD resistor on the diagonal between VCC pin and GPIO0 pin.
Now everything booted!
There are some tradeoffs you should be aware of when you squeeze in Espuna in this little module.
* The TX pin also drives the blue diode. If you, like me, want an indicator LED for wifi, you can not simultaneously have the serial terminal. LED pin and TX pin will collide, but fortunately the LED took over.
* The button is connected to the RESET pin on ESP-01s so it can’t be used like we are used to on other Espurna platforms. I’m sure you can modify that to, but this will cut it just fine for me.
I hope you had some use of my information.
