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Engineering Creativity for Neuroscience

 

 

BioStim V.8 Universal Biological Stimulator System

 

BioStim stimulators are very popular equipments, because they are

    - Sophisticated, top-grade, professional stimulators. They meet any difficult requirements in any biological laboratories.

    - They are user friendly. Despite their powerful features, they are easy-to-use. BioStim does not need special

      technical or computer skill. It is not a time consuming task to learn its usage.

    - Versatile equipments.

    - Compatible with every PC-based data acquisition system.

 

       Click on the picture to get it in full size

 

Our method is, how we improve the features of our BioStim equipments, that we collect all the notices and feedbacks from our customers. We receive ideas of our customers, and we implement their (may be your) knowledge into the features of BioStim.

 

The BioStim system must not be used in human experiments, because it has not got European permission for human applications.

 

 

The Parts of the BioStim Universal Biological Stimulator System

 

The BioStim system is divided into two functional parts. The time parameters are generated by the fully digital BioStim Controller, and the analogue voltage and current sources are implemented in the End-stages. The parts of the system are manufactured as independent equipments. On one hand it results a more flexible and variable system, because the similar parts (e.g. the End-stages) are compatible, and they can be changed easily. On the other hand the divided system meets the special experimental requirements much better, because the analogue End-stages can be located close to the biological objects in the shielded environment, but the digital BioStim Controller and the high voltage Battery Manager can be placed anywhere else. BioStim Computer Interface is an alternate of the BioStim Controller in special cases. You can find detailed descriptions about each components of the BioStim system in the appropriate paragraphs below.

 

The general overview of the BioStim Universal Biological Stimulator System is downloadable.

 

 

BioStim Dual-processor Controller V.8

 

In this description BioStim Dual-processor Controller is simply called BioStim Controller.

 

BioStim Controller is a dual-processor equipment. There are two independent RISC microcontrollers built into one cage. One of them, the Repetition Cycle and Gate Controller can be used to generate the periodic repetition trigger events, or it can be used as a gate generator to enable or disable the output pulse sequence generated by the Pulse Pattern Generator. The other microcontroller is the Pulse Pattern Generator. It is used to generate the different output pulse sequences (as listed below).

 

        Click on the picture to get it in full size

 

The accuracy of the time parameters in BioStim Controller are guaranteed by internal crystal pacers. All the programmed time parameters are stored in built-in nonvolatile memories. They hold the previously used values during switched off periods. Easy programming operations are carried out in menu system, with 4-button keypads. The displays of the microcontrollers are 4 x 20, and 2 x 16 character alphanumeric models with backlight to provide good visibility.

 

BioStim Controller (together with one of the End-stages) can be used as a stand-alone stimulator, but both of its microcontrollers have got bi-directional digital control capabilities: Start Input, Gate Input, and Synchron Output. These TTL-compatible control signals offer a huge versatility in the different applications. BioStim Controller can be started externally (with rising edges at Start Inputs) from another equipment (for instance a PC), or it can be the master synchron generator (if the external equipments are triggered from its Synchron Outputs), as well.

 

BioStim Controller has got nonvolatile memories to store all parameters of the functions. If you use the equipment in a fixed application, you should program it one time only. If you switch the BioStim Controller on, it checks, which function was used last time. After it the parameters used by the actual function are checked. If the parameters have got valid values preset, the last used function will be started automatically.

 

The human patient and user security instructions to use BioStim stimulators is downloadable. This document is available in Hungarian language.

 

The complete User Manual of the BioStim Controller, and the BioStim Computer Interface is available for download.

 

 

The operating modes of the BioStim Controller

 

Programming conventions, and definition of terms in connection with the BioStim Controller

 

The functions are categorized into two groups. The first group contains the 'single' functions. 'Single' functions are initiated by the START event. After a START event they generate their sequence one time only (an example is Single Burst). The other category is the group of the 'repetitive' functions. They repeat their sequence periodically based on an internal crystal pacer (an example is Continual Bursts).

 

A subcategory of the 'single' functions is the group of the 'delayed' functions. They are the same as their appropriate 'single' equivalents, but a programmable delay is occurring at the beginning of the sequence before the first Output pulse appears.

 

START event means a key-press on START button or a TTL rising edge appearing at the Start Input. The two source of Start event can be used together or independently any time (they are in logical OR relation).

 

You can clear all stored parameters if you press and hold F button down while BioStim Controller is switched on. During programming actions the equipment checks the validity of the actual value entered. If you try to accept (with F button) a number out of range, the software will not allow it. If more than one parameters are incoherent, you will be asked to correct them.

 

UP and DOWN button is used to navigate in menus and to modify parameter values up or down, respectively. F button is used to select a menu item or accept an input parameter value. Furthermore, F button is used to cancel a function if it is running. If you cancel a function with F button, you will get an access to Function Choice menu. START button is used to start the sequence of pulses, if a 'single' or a 'delayed' function is selected actually. The 'repetitive' functions can be interrupted temporarily with START button (and they can be restarted again with it).

 

 

The operating modes of the Repetition Cycle and Gate Controller in BioStim Controller equipment

 

Repetition Cycle:

 

This function can be used to generate periodic repetitive trigger events in such cases, when the BioStim Controller is the master synchron generator of the data acquisition process (in those cases, when the external data acquisition equipment, such as a PC, is triggered from its Synchron Output). In this function the Synchron Output of the Repetition Cycle and Gate Controller provides repetitive Start events for the Pulse Pattern Generator, on which any of the ‘single’ patterns should be selected. To use the Repetition Cycle function the Synchron Output of the Repetition Cycle and Gate Controller should be connected to the Start input of the Pulse Pattern Generator with the appropriate switch at the back side of the BioStim Controller. The repetition cycle time (Tc) can be set from 80 ms - 60 sec, with 10 ms of resolution. A wide (50 ms) Synchron pulse is generated at the beginning of every Repetition Cycle. These Synchron pulses are the synchron pulses of the whole time sequence, if the Repetition Cycle function is used and a ‘single’ pulse pattern is selected on the Pulse Pattern Generator. The Repetition Cycle and Gate Controller has got its own TTL-compatible Output, which is independent from the Output of the Pulse Pattern Generator. The Output pulse of the Repetition Cycle and Gate Controller (0.1 - 24.9 milliseconds in width, with 0.1 ms of resolution) can be optionally used for any other controlling task (for example muting the input of the preamplifier for a programmed period before appearing and during the stimulating pulse at the Output of the End-stage).

 

Gate Generator:

 

This function can be used to generate a programmed enabling period for the Gated Continual function of the Pulse Pattern Generator. To use the Gate Generator function the TTL-compatible Output of the Repetition Cycle and Gate Controller should be connected to the Gate Input of the Pulse Pattern Generator with an external BNC cable at the back side of the BioStim Controller. This combination of functions can be used to produce very long bursts of pulses. The duration of the burst is defined by the length of the output pulse set on the Repetition Cycle and Gate Controller. The duration of the pulses, and the pauses should be programmed at the Pulse Pattern Generator in its Gated Continual function. The gate time (Tg) can be set from 80 ms - 60 sec, with 10 ms of resolution. A wide (50 ms) synchron pulse is generated at the beginning of every Gate periods. These synchron pulses are accessible at the Synchron Output of the Repetition Cycle and Gate Controller.

 

 

The operating modes of the Pulse Pattern Generator in BioStim Controller equipment

 

The actually available 12 operating modes of the Pulse Pattern Generator in the BioStim Controller are presented in this document. They have got a graphical interpretation to explain them in fine details. In a few cases there are more than one function with which a paradigm can be carried out. You should always consider, which function is the best one for your special stimulating task.

 

 

BioStim Computer Interface V.4

 

There is an alternate equipment, BioStim Computer Interface in our choice to substitute the BioStim Controller in that cases, when a computer software is used to generate the sequence of stimulating pulses. BioStim Computer Interface has got a universal connector compatible with any End-stage manufactured by Supertech Instruments. BioStim Computer Interface has got a built-in power supply unit optimized for the End-stages, and it has two universal TTL-compatible digital input connectors. Its TTL inputs are configured in logical OR function internally. The TTL gold standard describes the voltage and load specifications of the inputs and outputs of a logic system, what is supplied from 5V. Nowadays most of the microcontrollers and logic systems use 3.3V of internal supply voltage. The logic signal inputs of the BioStim Computer Interface are universal, they accept the logic levels of the 3.3V, non-standard-TTL systems correctly with optimal noise margins, too.

 

Basically BioStim Computer Interface realizes (by hardware) the DC via Control function (see later in this description) of the BioStim Controller. If an appropriate software is used, what can generate the stimulating pulse trains, it is not necessary to order a BioStim Controller at all, it is enough to use the BioStim Computer Interface instead. The disadvantage of this arrangement is, that a fast computer, and a time-critical multitasking DAQ software is necessary to be used. An independent, universal, stand-alone stimulator can be formed only by using the BioStim Controller.

 

The complete User Manual of the BioStim Controller and the BioStim Computer Interface is available for download.

 

 

Battery-supplied (Monopolar) Floating End-stage (Stimulus Isolator) V.8 and Battery Manager

 

Battery-supplied Floating End-stage is the most sophisticated stimulator end-stage construction in the choice of Supertech Instruments. This End-stage is supplied from its built-in rechargeable battery pack. The Battery-supplied Floating End-stage can be used even in the most sophisticated, highly noise-sensitive microelectrode experiments (for example multi-electrode patch clamp environments). It passes extremely small, practically zero hum noise into the biological tissue. This version of End-stage is optimized for that aspect, that it does not generate any electric hum noise, because of this battery-powered scheme. According to this feature it can be placed close to the experimental object anywhere, even in a seriously shielded environment.

 

        Click on the picture to get it in full size

 

Battery-supplied Floating End-stage can be used either in microelectrode experiments or in body surface applications on animals. There is a Constant Current generator and a Constant Voltage generator built into this End-stage. The output of the End-stage can be switched between Constant Current and Constant Voltage modes on-the-fly, during the experiment. It is a very useful feature, because the first stimulating trials can be carried out in the secure Constant Voltage mode. If the experiment is qualitatively working, the End-stage can be switched immediately into Constant Current mode, where the electric charge can be defined and calculated exactly. The Constant Voltage mode has got two ranges: 10 V, and 100 V of full scale. The Constant Current mode has got two ranges: 100 µA, and 10 mA of full scale. The output amplitude in the selected range can be set using a 10-turn calibrated helical potentiometer on the front panel. The nonlinearity (total amplitude error) of the End-stage is less than 5%. The output leakage current is internally trimmed to nearly absolute zero, it is less than 1 uA.

 

Battery-supplied Floating End-stage has got an additional accessory, the Battery Manager unit, which is an automatic and precision battery charger and conditioner equipment. The nominal voltage of the internal battery pack is 120 V, and its nominal capacity is 170 mAh. The only disadvantage of the Battery-supplied Floating End-stage is, that it is not a very comfortable equipment, because the battery pack requires the continuous care of the user. If the End-stage is forgotten in switched on state for a prolonged period, the internal battery pack will be ruined.

 

        Click on the picture to get it in full size

 

The Battery-supplied Floating End-stage and the Battery Manager units are connected together with a high-voltage cable. This way the Battery Manager equipment can be placed outside of the shielding Faraday-cage.

 

Battery-supplied Floating End-stage has got its own, optically isolated, standard TTL control input. If your PC-based pattern generator (or universal DAQ) program has a hardware interface with standard TTL digital pulse pattern output, it is not necessary to order a BioStim Computer Interface, because the Battery-supplied Floating End-stage can be connected directly to that digital output.

 

The complete User Manual of the Battery-supplied Floating End-stage, and the Battery Manager is available for download.

 

 

Universal (Monopolar) Floating End-stage (Stimulus Isolator) V.7

 

This equipment is unavailable as a product in stock. Generally please choose Battery-supplied Floating End-stage (stimulus isolator) V.8 and Battery Manager.

 

The stimulating circuitry, the outer looking and all the specifications of the Universal Floating End-stage are the same as they described above at the Battery-supplied Floating End-stage. This version of End-stage is designed for the aspect of the user comfort. It generates a bit more hum noise than the Battery-supplied Floating End-stage. However it can be used in many of the microelectrode experiments or in body surface applications on animals. We manufacture it for unique orders.

 

The floating output circuit of the Universal Floating End-stage is supplied by an internal high frequency power source. The isolation capacitance between the mains plug and the floating output is less than 10 pF. It is good enough for most of the microelectrode experiments.

 

To use the Universal Floating End-stage a BioStim Controller or a BioStim Computer Interface is needed, because they should provide the necessary low voltage supply and the universal logic inputs for the operation of the End-stage.

 

The complete User Manual of the Universal Floating End-stage is available for download.

 

 

Bipolar Floating End-Stage V.2

 

The technical details will be published soon.

 

 

Fast LED Driver End-stage LE-4x

 

Fast LED Driver End-stage can be used for Optogenetics, Retinography and other light stimulating applications. It can drive any kind of LED directly, with calibrated current, independently of the LED model, even the extremely high forward voltage LED types. It provides an output current of 55 mA or 110 mA full scale. The range is switch selectable. This LED Driver End-stage is compatible with BioStim Dual-processor Controller and BioStim Computer Interface. Its internal construction is based on a high precision constant current circuit and a high speed gating circuit for extremely fast switching of the LEDs.

 

There is a very special feature implemented in the design: Overdrive Protection Circuit, what never allows to override the full scale current, even not in transient or broken output wiring conditions! It is an extremely important feature, because the brightest, highest power LEDs are driven by such level of currents, what are very close to their absolute maximum ratings. Even these LEDs are terribly expensive.

 

        Click on the picture to get it in full size

 

Technical data:

 

The selectable ranges of the output current:

    5 to 55 mA in 11 steps (5 mA each step)

    10 to 110 mA in 11 steps (10 mA each step)

 

Compliance voltage of the current generator: 13.5 V

 

Worst-case error of the output current generator: < 2 %

 

Active current sink circuit built-in to eliminate the parasite charge holding effect of LEDs

 

Overdrive Protection Circuit: the full scale is never overridden

 

To use the Fast LED Driver End-stage a BioStim Controller or a BioStim Computer Interface is needed, because they should provide the necessary low voltage supply and the universal logic inputs for the operation of the End-stage.

 

 

Fiber Optic Transmitter and Fiber Optic Receiver

 

They have been designed to use the BioStim Universal Biological Stimulator System in MRI and FMRI labs. The stimulator End-stages manufactured by Supertech Instruments are MRI-compatible. The Fiber Optic Transmitter / Receiver equipment pair is a single-channel, high voltage tolerant. noise insensitive, isolated, digital signal transmission line. Due to them the End-stage can be positioned close to the animal in the high magnetic field area while the BioStim Controller or the BioStim Interface can be located in the control room.

 

The top of its basic application field the Fiber Optic Transmitter equipment can be used for Optogenetics, Retinography and other light stimulating applications in MRI and FMRI labs. In other words it can behave as a Remote Optic Stimulator End-stage. Its output light can be transmitted directly by the optical fiber to the animal located in the high magnetic field. The wavelength of the Fiber Optic Transmitter is 660 nm. Its output optic (light) power is 1mW.

 

Please call or email us for further information.

 

 

Prices

 

You can find the general conditions at the beginning of the Price List page.

 

BioStim Controller V.8 (dual-processor version): 900 EUR

 

BioStim Computer Interface V.4: 400 EUR

 

Battery-supplied (Monopolar) Floating End-stage (Stimulus Isolator) V.8, including the built-in rechargeable battery pack: 700 EUR

 

Bipolar Floating End-Stage V.2, constant current output, including the built-in rechargeable battery pack: 1050 EUR

 

Battery Manager V.3: 480 EUR

 

120V rechargeable battery pack (for replacement purpose): 240 EUR

 

Constant Current Fast LED Driver End-stage LE-4a: 330 EUR

 

Fiber Optic Transmitter / Remote Optic Stimulator End-stage (660 nm, 1mW), single-channel equipment in a small plastic enclosure, compatible with the BioStim Controller or BioStim Computer Interface: 270 EUR

 

Fiber Optic Receiver (660 nm), single-channel equipment in a small plastic enclosure, supplied from a wall plug DC power supply (included in the price): 240 EUR

 

Fiber Optic Receiver with built-in 13.5V floating power supply to control the remote Universal Floating End-stage: 540 EUR

 

Optical fiber, 5 m, assembled with connectors: 50 EUR

 

 

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