The Kastle is an open-source instrument that runs on two Attiny 85 chips that you can reprogram with an Arduino. One of those chips handles the sound generation while the other is tasked with modulation and due to the DIY nature of the device, those two components can be tweaked to change their parameters. What's more, Bastl Instruments says the LFO and OSC chips can be swapped out entirely for different ones.

The compact synth offers three modes: phase distortion, phase modulation and track and hold modulation. There are also pitch, timbre, wave shape and LFO controls that can be patched in different configurations with the included cables. Two I/O CV jacks are also on board for routing sounds to other gear. While it does offer a different look and feel to the Teenage Engineering devices we've spent time with in the past, the Kastle is slightly more expensive. To snag one, you'll need to hand over €65.60 (about $73) and the instruments are set to ship next month. For now, you can catch the Kastle in action via the video down below.