8BitMods has released a firmware update for the Memory Card Pro (MCP002) and Memory Card Pro 2. These two memory cards for the original PlayStation or PS1 can now be used as a Bluetooth receiver, which is mentioned in the corresponding Wiki entry.
For now, only two controllers with Bluetooth LE support are officially compatible with the receiver. The first one is the 8BitDo Ultimate 2C BT/2.4G, while the second one is Microsoft's well-known Xbox wireless controller, which is available from $45 on Amazon. There are numerous different variants of the latter, and many of them should work according to 8BitMods.
In order to use the controller on a PS one, both the controller and Memcard Pro must be put into pairing mode, which stays active for 60 seconds. By default, the Memcard Pro should remember controllers that have already been paired, but this feature can be disabled if needed.
That said, there is one significant limitation. Under no circumstances should a wired controller be hooked up to the same port as the Memory Card. According to 8BitMods, this could potentially damage the PlayStation 1 console.
This new Bluetooth receiver feature is also partially available on the original Memory Card Pro with the model number MCP002. Unfortunately, there's no software update for the first revision (MCP001), but retro gamers who have purchased the first revision from certain retailers can now get a new Memory Card Pro or Pro 2 at a generous 40% discount. However, these memory cards are currently sold out and can only be pre-ordered.
Last but not least, the number of supported controllers is supposed to grow. 8BitMods has already announced that it will add more controllers to the official compatibility list, but it’s unknown which exact gamepads are in the works.