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Hi,

A wirelss circuit is mounted on the Rat's head to record Rat's brain acitivity. The board transmit the data to its receiver sitting outside the Rat's cage. The RAT will be awake and moving around in its cage, and the transmitter will be sending the data continuously for days. The problem is that we do not want to interruput the recordings and the transmitter battery dies after every two hours.

So, We thought that lets power up the transmitter circuit wirelessly.

The transmitter circuit requires 3.3 volts and 0.26mA of current. I was wondering that how can I measure the field produced by the coils in different parts of the cage.

  1. Can anyone recommed any simple technique or device or circuit that can help me to do that?

  1. How can design the antenna for the transmitter board that can be easily mounted area equal to the size of the head of the RAT?

  2. Is there any mathematical relationship between the magnetic field intensity and the antenna design?

Please advice!

Regards,

John

Reply to
john
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On a sunny day (Thu, 26 Nov 2009 13:57:41 -0800 (PST)) it happened john wrote in :

Use photocell? Does 'rat' need darkness?

Reply to
Jan Panteltje

If so, use infra-red photoemitters. Neither us nor that rat can see

850nm radiation, and silicon photocells are maximally sensituve to 850nm radiation.

But make sure that you don't need so much IR that you risk cooking the rat.

-- Bill Sloman, Nijmegen

Reply to
Bill Sloman

How many signals? The usual ECG bandwidths?

Steve Roberts

Reply to
osr

My advice to Rat is to hang with a different group of grad students!

--
www.wescottdesign.com
Reply to
Tim Wescott

Two ideas

  1. Install a magnet coil and DC rectifying diode wired to the battery. Install a running wheel with strong magnets glued to its periphery. The Rat will charge the battery for you while it exercises. Now on to next problem as how to keep induced RF and EM fields out of Rat brain and sensor as not to affect scientific results.

  1. Install two batteries in parallel and change one or other on frequent basis.

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Use only Genuine Interocitor Parts" Tom Servo  ;-P
Reply to
RFI-EMI-GUY

Hi,

No, the rat does not need the darkness. But do the photocells have enough current and voltage to charge the battery. and can you recommend some of them.

John

Reply to
john

If you only need a very small current, a few milliwats, a simple inductive pancake loop around the inside of the cage should provide enough power. A few tens of turns in a bundle should do the trick.

Alternatively, if there is always light, even ordinary leds can function as low power solar cells and they can be very small and lightweight...

Regards,

Chris

Reply to
ChrisQ

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