Wednesday, September 17, 2014

ISL Stage 4C Delivery

We ship to ION the devices shown below. There are five Implantable Sensors with Lamp (A3030A). These are encapsulated in acrylic, clear epoxy, and clear silicone. They do not include EEG monitors, but they can be commanded individually, and instructed to perform extended optical stimuli with a single command. All five have 100-mm long stretched helical leads and through these they deliver 40 mA to an implantable lamp.



Figure: ISL Stage 4C Deliverables. We have (1) Rubber Duck antenna, (2) telescoping half-wave antenna, (3) Command Transmitter, (4) Head Fixtures A3024HDC-B, (5) Implantable Lamps Circuits A3030A.

There are five Head Fixtures (A3024HFC-B). All produce blue light. The power output from the taper tip at 40 mA forward current is written on the top of their petri dishes. Head fixture No3.1 produces 18 mW, which it obtains from a total lamp output of 34 mW. Its coupling efficiency is 53%, which is a little over our theoretical maximum, and 3.4 mW higher than our previous best head fixture. Another head fixture provides 15 mW. For more details see here.

The Command Transmitter (A3029A) is programmed to transmit serial commands to the ISLs. We plug LWDAQ power into its RJ-45 socket, and 24-V boost power into its power jack. We do not include a boost power supply in our ISL4C shipment. The boost power supply from the ISL4B shipment is still at ION, and will do the job. Note: we sometimes have to reset the LWDAQ Driver before the green power light illuminates on the A3030A.

We operate the Command Transmitter (A3029A) with our new ISL Controller tool, which you can download here. Place the TclTk text file in your LWDAQ Tools folder, or run it with the Run Tool option, and a window like the one shown below will pop up.


Figure: ISL Controller Tool in LWDAQ Software. The A3030A does not provide data transmission (Xon and Xoff).

The A3030A does not support randomized pulse generation. But it does support lamp dimming to 0%, 20%, 40%, 60%, 80%, and 100% of maximum intensity. The ISL Controller allows you to select the lamp intensity with a menu button. We can send the stimulus command to all A3030As or to an individual A3030A. We select channel 1-14 for individual devices, according to the serial number label on its battery.

We ship two antennas. One is a telescoping half-wave 146-MHz antenna. With this antenna we obtain reliable reception at ranges 0-1 m. The other is a short, flexible antenna (called a "rubber duck" antenna). With this one, we obtain reliable reception at ranges 0-50 cm.

We hope that ION's implantation of these devices will answer the following questions. Does the encapsulation resist condensation and corrosion? We have clear encapsulation to allow us to examine the devices after explantation. At what range is command reception reliable? What lamp power is required to provide stimulation, and what pulse length and frequency is optimal for stimulation?

We will visit ION on 16-OCT-14 to measure the operating range. In the meantime, we will start work on the A3030B, the same circuit as the A3030A, but with the EEG amplifier and data transmitter loaded.