Echo Knob by el Garatge. 
The Echo Knob is a tiny LFO (Low Frequency Oscillator, aka ramping) that connects to your pedal expression input to automate it. It also allows you to record a custom pattern that will play in loop. It is powered with 9V center negative as most pedals.
 
Despite having just a single button and knob, the Echo Knob packs a good amount of features:
Two operation modes: LFO and Echo. Double press to swap between modes.
LFO mode: Sends an oscillating signal to pedal. Rotate the knob to change speed. Button + Knob will change LFO shape (triangle, square, random) and also depth (check diagram).
Echo mode: Allows to record and play a custom knob movement. Hold button to REC and release to play automatically the recorded pattern (up to 10 seconds). When holding REC, the LED will blink shortly to indicate it’s starting to record.
A simple usage for it is just recording an incrementing/decrementing value to get a saw shape.
Single button press to play / stop in any mode, being very easy to start and stop the LFO.
When stopped, the knob will behave exactly like an Expression Knob, allowing you to control expression manually. Press the button once again to start the LFO / Echo pattern again depending on the current mode.
LED indicates the current expression value being sent to the pedal.
Designed to fit Chase Bliss Audio pedals, check device size for other brands, especially if they have other connectors near the expression one.
Hidden ultrasonic mode: LFO speed is multiplied so it can reach almost audible range.
How to use it:
Once connected to your pedal’s expression input, when powered up the Echo Knob will start in LFO mode (triangle shape, full depth), the LED will blink like the triangle shape. Current LFO speed will depend on knob position. Press the button once to stop the LFO and select manual expression.
If you already have a Chase Bliss pedal with ramping, it allows you to easily start/stop the LFO without having to touch the tiny dip-switches (internal ramping is disabled when connecting the Echo Knob), in addition to 3 LFO shapes with configurable depth. It also allows you to record custom expression patterns. Another example are the Automatones, which don’t have internal ramping and could especially benefit from this device.
For other pedal brands, you can create vibrato-like effects, add motion and possibilities to pedals that didn’t have this option but that are provided with an expression jack input. It will especially benefit from pedals with a wide range of expression options like Strymon, Meris, Eventide, Empress, Hologram Electronics, Chase Bliss Audio…
 
 
The Expression Knob
The Expression Knob is the smallest expression “pedal”. It allows you to control a pedal’s expression without losing any space on the pedalboard. It connects directly to the pedal without needing any cable.
Usage examples (may depend on each brand):
Multiple parameters: Changing multiple parameters at once if the pedal allows it via expression.
Limiter: In brands like Chase Bliss Audio and others, you can set a max value from a pedal knob and all the expression range will only move within the selected range, adding more precision.
Knob is made of CNC-machined aluminum. The rest of the body is made with nylon.
Works with many brands: Chase Bliss Audio, Meris, Strymon, Hologram, EHX, Empress, Fairfield Circuitry, Cooper FX, Walrus Audio, Montreal Assembly (CT5), Red Panda, Spaceman Effects, DryBell, EarthQuaker Devices, Pigtronix, Eventide…