C64-WiFi-Modem-User-Port

A NodeMCU (ESP8266) based WiFi modem for the C64's user port This is a Wifi-Modem for the Commodore C64 Uperport, which is based on the ESP8266 (NodeMCU v3). It contains level shifters to translate between the NodeMCU 3.3V level and the User Port 5V level. This prevents stressing the User Port due to a level mismatch.

Further on, status LEDs and (in Rev. 1) a Reset switch is contained.

About the NodeMCU v3: There is a version, which is wider. The version that work is WeMOS NodeMCU v3, which is about 25.4mm wide. You can compare it to this picture, please. The right one has the labeling of the pins parallel to the edge of the PCB.

The wiring follows the instruction on https://1200baud.wordpress.com/2017/03/04/build-your-own-9600-baud-c64-wifi-modem-for-20/

The firmware, required for the NodeMCU, can be obtained from the same website. Please follow the setup procedure described there.

Now, the STL files for a 3D printed case are available for this project.

There are three types of reset switch plungers for some common tact switch heights (4.3mm, 5mm and 7mm).

Rev. 1 works well, but only accepts the (smaller) WeMos NodeMCU v3 (approximately 48mx25mm). There is a bigger version available from the common sales platforms, which are bigger: 31mm x 57mm and don't fit the footprint of Rev. 1. This led to Rev. 2, which is now tested and working completely.

Both sizes of the NodeMCU

WiFi Modem Rev. 2 in case

A nice blog about this project can be found here: GozdniJezek: C64-WiFi-Modem-User-Port by Sven Petersen (Commodore WiFi modem)

Recommended Screws

For the case, I have used 2.9mm x 9.5mm (self taping) screws for sheet metal (C 2,9x9,5H, DIN 7981).

Calculation of the Component prices

The prices of the components was summed up. The total costs without the 3D printed case and any shipping fees is 16.19€ (May 2020). This might differ, depending on the source of the parts the Node MCU v3 can be obtained from non-domestic sources for less.