Light, small and compact
The compact (14 x 10.5 x 7mm) and lightweight design (1.2gr) of the BlueBerry along with its ease of implementation and open source nature make it an ideal candidate for optogenetic studies on small freely moving rodents such as mice.
Battery
The battery-powered approach in designing BlueBerry enabled its use in various large scale environments without the need to adjust the experimental arena for wireless power transmission. BlueBerry uses special small Li-Ion rechargeable coin batteries from VARTA.
BLE communication
The BlueBerry includes a dedicated stand-alone bluetooth module (RN4871) responsible for receiving all necessary optogenetic stimulation protocol/channels.
Dedicated PCB
All electrical components are interconnected and mounted through a standard 2-layer compact PCB design.
Electronic components
The design utilizes readily available electronic components. A microprocessor (ATtiny85), is responsible for decoding all Bluetooth packets and delivering high-power pulses to the output channels via a two-channel MOSFET. This setup ensures efficient and reliable processing and control, leveraging the capabilities of standard, commercially available parts.
Standard connector
LED pulses are routed through standard miniature connectors, offering flexibility in the design of brain implants.
Interfacing the brain
Output channels of the Blueberry are plugged into a connector interfacing with implants fixed beneath the animal's scalp targeting either cortical layers or deep brain structures through customizable implants.
Superficial stimulation
Targeting superficial cortical regions using miniature high-power LEDs (60mW) mounted on flexible PCBs.
Deep brain stimulation
Targeting deep-brain regions by coupling high power LED with an optical fiber.
BlueHub control unit
The BlueHub is a dedicated control unit for the BlueBerry system, designed to seamlessly integrate with any neuroscience behavioral framework.
Interfacing with closed-loop behavioral frameworks
Featuring four BNC channels, the BlueHub accepts trigger inputs from external systems when behavioral events are detected or optogenetic stimulation is needed. Its OLED screen interface allows users to configure and assign tasks for each input, such as specifying which BlueBerry device to activate and defining the corresponding stimulation parameters. All input control, parameter adjustment and sending Bluetooth packets are done through a WiFi Arduino module.
Charging stations
The BlueHub includes multiple integrated charging stations, allowing convenient recharging of BlueBerry devices. Each station is designed to securely accommodate the micro connectors of the BlueBerry system, ensuring a reliable and efficient charging process.
BlueBerry base configuration
The BlueHub also features a dedicated programming station, allowing users to initialize freshly manufactured BlueBerry devices or update to latest firmware. This station facilitates the one-time upload of the base BlueBerry software onto both the microcontroller and the BLE (Bluetooth Low Energy) module without any need of programming knowledge.