esp-link telnet adapter

OK, this makes me a bit annoyed. I get people wanting to make money and not open sourcing things, but the wifi232 made a big splash and now it’s been literally three years since they were sold out and there’s no indication that they’ll be back ever again. If anyone has one and wants to mail me one I happen to know how much protection the esp8266 has to prevent just dumping the entire code memory as a binary file (it’s none!). Until then we have to deal with other wifi modem firmwares. I saw the the Retro Wifi SI in a recent hackaday post and while it’s good, it’s also a little expensive (and shipping to the US is also expensive). I also don’t exactly need a full modem, just a virtual serial port to telnet adapter. I decided to use the esp-link firmware that I’ve used before to just set up a super simple transparent serial link. Combining that with a d1 mini, a couple LEDs, a 3.3v-5v level shifter board, a max232 breakout board, and a db25 and shell makes this:

Things to remember: redirect the debug output somewhere other than the main serial pins, swap the main serial pins so the esp doesn’t barf on boot at a strange baud rate. Use the latest (3.0+) firmware to get baud rates less than 9600. If you have a max3232 breakout board you no longer need to double amplify the signal, it will work straight from 3.3v.

One Response to “esp-link telnet adapter”

  1. ESP232 code enhancements/porting | Evan's Techie-Blog Says:

    […] time ago and am just now bothering to write something up for it. I was not super satisfied with the esp-link telnet adapter software, and I wanted to make some smaller simple boards. Enter the […]

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