I've designed a board which plugs onto a raspberry pi zero to provide WIFI through an ESP8266 module on the serial port of the Raspberry pi.
Now you may say: Why not just use an USB-wifi dongle? Those are cheap and work out-of-the-box! You're right. But in some cases that's not the best solution: When you are space-constrained and need exactly ONE usb device, not having to use a HUB pays off.
I have not yet soldered on the connectors in these pictures, to facilitate other configurations should that turn out to be practical.
So...
If you think this is useful, If you have some programming skills, If you have a use for this.....
I have the following offer: At the cost of the components (EUR 2.50 for the ESP, EUR 1.00 for the PCB+ rest) and shipping (max EUR 5.25) I can send you one. The deal is that you'll try to make the wifi part usefull....
Of course, developing the software is probably more convenient on a "bigger" pi.
Should something essential be hooked up wrong. We'll respin the board and get you a new version. No charge. The main reason that I'm not giving the hardware away for free initially is that I don't want people to say: oh, it's free, lets get it, I'll decide later if I need it/can help and then of course nothing happens. By asking for a little bit of money I force people to think about it and scare away the freeloaders. Also, the offer applies "as long as supplies last", i.e. whenever I think there is enough activity...