I recently purchased an air quality monitor I want to play with. It uses a TTL serial interface. While I could connect it directly to a Raspberry Pi (and eventually plan to do so), to start I want to have it connected to my PC to do some experimenting.
I found this guy had connected the AQ monitor using an Adafruit FT232H board rather than using the typical FTDI cable. The advantage to the FT232H board is it can provide the 5V the AQ monitor will need and yet it will handle the 3.3V data signals.
This post just covers getting this breakout board working on my PC. This should have been quick and easy but of course I had problems …
Once you have the breakout board and the pins soldered, you need to get the FTDI drivers installed. According to the manual, for Windows 10, when you connected the FT232H to the PC, the drivers should simply be downloaded from Microsoft.
This did not work automagically for either of my Win10 systems.
Configuring FT232H Drivers
When I inserted the FT232H, I received this in device manager:
To install the driver I right clicked on ‘Unknown Device’, selected Update Driver and then Search Automatically. The driver was located, but no new device showed up in the Ports section. Notice below, though, that USB serial converter does appear in the USB controllers section:
At this point, I wasted way too much time going down multiple rabbit holes trying to figure out why the COM port was not being assigned.
The trick was found here:
Click on right click the USB Serial Controller and select properties:
Select the advanced tab, then select Load VCP:
Finally, update the driver again and viola, the FT232H shows up as a COM port:
Testing the FT232H Breakout Board
To test, I put the breakout board on a small breadboard and tied the TX/RX lines together (D0/D1):
Next, start up Putty and configure it for serial operation:
Once connected, what you type will be echoed on the screen as the TX is looped back thru the RX line: