The Zeno is an acne treatment device with disposable tips that are electronically limited to 45 or 60 uses. Matt did a system teardown that revealed a Cypress cy8c27443 microcontroller in the main unit and a 128byte I2C EEPROM in the tip. He used the Bus Pirate to sniff I2C traffic going to the EEPROM in the tip, and then used standard I2C EEPROM write operations to reset the use counter.

It’s amazing where you find microcontrollers, and this is a fantastic use of the Bus Pirate. However, this hack tampers with an FDA-approved medical device that controls heat applied to the skin. An interesting academic exercise, but please don’t reuse the tips!

Via the forum.

Don’t know what a Zeno is? Us either. From the website it sounds like a pimple heater:

Zeno is a hand-held battery-operated device designed with a tip that heats to a pre-set temperature…. Specifically, Zeno stimulates a heat-shock response in p. acnes, the bacteria causing at least 90% of all acne blemishes. Heat shock proteins, activated by bacterial cells under heat stress, cause the self-destruction of p. acnes within the lesion, reducing inflammation and allowing the skin to return to a healthy state.