I'm working on a project to implement live CANbus telemetry over wifi. I'm using the Feather M4 Express to read CAN and publish MQTT messages and I'm using the ESP32 Featherwing for WiFi connectivity. I want to increase the range by adding an external antenna to the ESP32 which I've seen people do by scraping off the coating on top of the antenna traces and soldering on an SMA connector. I tried this but managed to tear antenna traces from the board. I planned to buy another coprocessor and try again with more care but wanted to see if there were better options before doing so.
Some notes:
- I'm looking for ~>100-200M of line-of-sight range. I've considered LoRa and GSM but prefer to stick with WiFi for the ease of implementation and ubiquity. I believe that my desired range is feasible with a decent gain (~5 dBi) antenna on the ESP32 and a decent router, though am open to feedback on this as well.
- I would be interested in a single MCU that supported WiFi (with external antenna support) and CAN support but haven't found an option that beats the M4 Express + WiFi featherwing option for ~$40-$50.
Extending the range of the ESP32 Featherwing Coprocessor
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Please be positive and constructive with your questions and comments.
- justinwald99
- Posts: 2
- Joined: Wed Jun 23, 2021 10:13 pm
- adafruit_support_mike
- Posts: 67446
- Joined: Thu Feb 11, 2010 2:51 pm
Re: Extending the range of the ESP32 Featherwing Coprocessor
Adding an active antenna would change the emission profile, which would trigger a requirement for recertification with the FCC.
A passive directional antenna would be okay though. That just redistributes the existing energy.
Wifi has a nominal range of 50m, which admittedly means lab conditions on a good day, but people have gotten crazy distances with appropriate antennas.. I think the current record is something like 300km between two mountains in Italy:
https://en.wikipedia.org/wiki/Long-rang ... able_links
and links of a few miles are fairly common. It shouldn’t take much to get a few hundred meters.
The existing community of people doing long range WiFi will be an excellent source of design and application knowledge with a solid engineering history. You can save months or years of direct testing by seeing how other people have succeeded and failed.
A passive directional antenna would be okay though. That just redistributes the existing energy.
Wifi has a nominal range of 50m, which admittedly means lab conditions on a good day, but people have gotten crazy distances with appropriate antennas.. I think the current record is something like 300km between two mountains in Italy:
https://en.wikipedia.org/wiki/Long-rang ... able_links
and links of a few miles are fairly common. It shouldn’t take much to get a few hundred meters.
The existing community of people doing long range WiFi will be an excellent source of design and application knowledge with a solid engineering history. You can save months or years of direct testing by seeing how other people have succeeded and failed.
- justinwald99
- Posts: 2
- Joined: Wed Jun 23, 2021 10:13 pm
Re: Extending the range of the ESP32 Featherwing Coprocessor
Thanks for the response! I was amazed by the videos I saw some people posting with WiFi. Some people have gotten ranges of ~300M with just a good router and the pcb antenna on the ESP. I'll continue trying some different options and being more careful when soldering the external antenna.
- adafruit_support_mike
- Posts: 67446
- Joined: Thu Feb 11, 2010 2:51 pm
Re: Extending the range of the ESP32 Featherwing Coprocessor
Yeah, it’s a realm of technology with a lot of “hold my beer and watch this!”, but that’s okay because the “watch this” often pays off well.
Please be positive and constructive with your questions and comments.