Brainvision hacks
This page last updated 2023/07/01
Introduction
This is a list and explanation of some hardware hacks for brainvision products, specifically the actichamp line of products. Some of this information could be used to repair, repurpose, or upgrade old hardware.
Auxiliary input hardware
Building custom AUX hardware for the actichamp is relatively easy. The AUX ports built into the actichamp are BINDER Female 5-pin panel mount connectors, Part #s 09 9792 30 05 or 09 9792 20 05 and custom hardware can be built off of the handful of options for the matching male connectors: two with cables (2 meters #79 9005 12 05, and 5 meters #79 9005 15 05), and two without (standard #09 9789 71 05 and slim #09 9789 00 05).
Pinout for the male binder cables noted in the paragraph above. With the notch oriented up, (1) is top left, numbers ascend counter-clockwise. (1) is +5V power, (2) is positive polarity recorded signal, (3) is ground or neutral voltage to which the signal should be compared. (4) is the negative polarity recorded signal, (5) is -5V power. Wire colours are only applicable to the connectors above with cables. Note female pinout on the amplifier itself is the mirror image of this pinout; (1) would be on the top right (notch oriented up), with numbers ascending clockwise.
Photosensor wiring diagram. The photosensor depicted is a SparkFun Ambient Light Sensor Breakout, TEMT6000. More intense incoming light results in a higher analog voltage on the signal pin. VCC on the photosensor should be connected to the (1) +5V pin, ground to (3) ground, and the photosensor signal channel should be connected to the (2) +Line.
Electrocardiogram (ECG) wiring diagram. International Electrotechnical Commission (IEC) lead colours are presented in the figure. The equivalent lead colours for the American Heart Association (AHA) would be Black-Green-White, instead of Yellow-Black-Red, respectively. If constructing an ECG lead, I suggest using snap electrode leads and the complementary snap foam electrodes typically used for ECG administration.
Refurbishing the Powerpack
The older Brainvision Powerpacks contain sealed 3-cell lead-acid batteries. Specifically, they contained a 6V 6.5Ah Exide A506/6,5 S. The battery itself is not particularly remarkable, but it's size is, if you intend on replacing the battery while maintaining the form factor. The original Exide battery is 5-15/16×3-11/16×1-5/16" or approximately 150×95×35mm. Not the most common 6V battery size, but RS Power's RS67 6V 7.2Ah and AJC's C7S 6V 7Ah batteries are almost identical fits with the original. The original battery is attached to the charger board with female spade terminals (on the board side) and it is very simple to remove and swap out a different battery. I would not assume that the battery pack remains MR compatible, if it was already, and this will most definitely void the warranty.
Original battery inside the powerpack.
Replacement battery fit.
Change log
2023/07/01: Initial version w/ AUX setup and powerpack battery replacement.