Venus 2000 Modifications
First Generation

The Venus 2000 is a machine designed to stroke the penis. It can be ordered on-line from here. When shipped from the manufacturer, the device is controlled by a small hand held box which contains an on/off switch, a power indicator, and a variable resistor.  In order to control this device from a computer, we need to replace the functions of this control box and also add some kind of sensor, so the computer can monitor the stroke speed and position.  It was an important consideration to me that the Venus 2000 would continue to be able to be used as it was originally intended, IE with the original remote control.

Rotation Sensor rotation sensor

The images above show the first generation of rotation position sensor. This was fabricated using a reed switch from Radio Shack. I removed the magnet part from it's white housing, and mounted it on the Venus flywheel, while the switch side mounted on the homemade bracket.  The magnet was positioned such that, it activated the reed switch when the Venus was at the bottom of a stroke.  This admittedly crude sensor actually performed quite well.

The first generation Venus speed controller was made using 6 relays controlled from the laptop's parallel port.  I used a commercial product similar to this one from 
Carl's Electronics.  The hand held factory controller uses a 10K variable resistor to control the motor's speed.  Unfortunately the resistor is not referenced to ground.  The Venus 2000 uses a commercial speed controller manufactured by Quantum Controls, a maker of OEM circuits for controlling DC motors. Because the variable resistor is not based on a voltage referenced to ground, providing the controlling signal is not as simple as using a D/A circuit.  The simplest solution was to use relays with a resistor ladder network.  I used 6 relays, which were activated in a binary pattern to create 64 different possible motor speeds.  Click here to see a schematic of this first generation of Venus 2000 speed control.

If you analyze this circuit, you will see that it is far from a perfect emulation of a variable resistor.  First of all, the overall resistance varies from 5,700 ohms up to 12,630 ohms depending on the selected setting.  Also note that the highest output possible is the "mid point" setting.  Despite these flaws, the relays actually worked quite well controlling the Venus 2000 speed. For one thing, the area of interest for me was the lower portion of the speed range.  I find the faster speeds to be less interesting.  

Second Generation

The first generation design was used for about 12 months with good success, but I wanted a better solution.  basically, I wanted a better simulation the variable resistor.  I started experimenting with this chip.  At first I tried using two chips in series, one for the lower portion of the variable resistor and one for the upper portion.  I eventually found that there was no need for the lower portion to be simulated.  It was enough to have a (simulated) variable resistor just between the "hot" leg and the "wiper" leg.  Here is the resulting schematic for the second generation interface to the Venus 2000.  This schematic also shows the receiver circuitry for the output from the reed switch.  The second generation design is still in use at the time for the most part, except a circuit board has by now been mounted inside the Venus 2000's motor enclosure, and the position sensing has been upgraded to photo sensors in preparation for the third, and hopefully final generation of Venus 200 interfaces.

Third Generation

The second generation design has been in use for about 12 months, but I still feel there is room for improvement.  In the third generation design, I have added the ability to sense the receiver movements.  I believe this may enable the computer program automatically adjust the level of stimulation to be as high as possible while still preventing orgasm.  There are three parts to this third generation design.  The first part is shown in the images below:

venus motor mods venus motor mods venus motor mods

In these images you can see that I have designed and mounted a new PC board inside the Venus 2000 motor housing.  This PC board incorporates the simulated variable resistor, a relay for turning motor power on/off, and two photo reflectors for very precise sensing of the fly wheel's rotational position.  Look closely and you can see that I have mounted an optical wheel on one side of the Venus 2000 flywheel.  In the middle picture, you can see the new front panel connector I mounted for connections to this new PC board.  (Click on the images for a larger view.)  Click here to see the schematic of this new PC board.  Here is what the PC board looks like.  The ground plane is used to help act as a heat sink for U8.  Two of the large holes are used to mount the PC board to the motor using hex standoff hardware.  The bottom most hole, must be enlarged enough to let the motor's shaft pass thru it without touching.  Also note that U2 is mounted at an angle.  This is to allows it to be at right angles to the encoding wheel.  U1 and U2 are positioned such that their signals are about 90 degrees out of phase.  The PC board shown here is presently in use, as the second generation interface has been modified to work with it.

Here are the files you need to produce your own PC boards. There are two files, the schematic and the layout. The schematic file is not strictly needed for manufacturing, but might be useful if you want to make any modifications to the board before production. These files work with the Express PCB service, download and use their free software packages to view, change, or order boards.
Note that after assembling the PCB, you will want to be able to adjust the position of the opto reflector devices. They need to be placed on the "back side" of the PCB, facing the encoding wheel. The PCB should be mounted such that these parts are about 0.050" from the encoding wheel. I mounted mine as far off the PCB as the component leads would allow, so that the parts can be shifted slightly from side to side. The idea is that the signals from the opto's will be out of phase with each other. The phasing is not critical, but you want the INDEX opto signal to be stable whenever the STEP opto has a rising edge. Also note that one of the "white" reflective stripes needs to be darkened in the area of the INDEX opto only. Here is a picture to show you the idea.
venus encoding wheel

Theory of Operation

The Venus Encoder Board performs 3 seperate functions. You can leave the board depopulated if you do not need all the functions.

The second part of this third generation design is a control box, shown in the pictures below.  From left to right are shown: the front view, a close up of the box's control buttons and the rear view.  I call this box the CS-2000.  The "CS" for being part of the the Controlled Sensations project, and the "2000" part since it controls a Venus 2000.   One of the great things about this new box, is that it can operate the Venus 2000 on it's own, or provide an interface for computer control.

CS 2000 Front View CS-2000 Buttons CS-2000 Back View

In the front view, you can see that the CS-2000 has 5 control buttons, 2 control knobs, and an LCD display screen.  If you look closely at the rear view, you will see connections for programming updates, the Venus 2000, a DB-9F for connection to a computer,  an air port for the small Venus 2000 air hose, an RJ-45 look-alike connector for the receiver stand sensor and a power connector.  

The CS-2000 has a number of built in programming sequences that can be selected from the front panel, these are:
Additional features include the ability to add or remove air under front panel control;  to display the minimum and maximum positions of the receiver;  and to automatically remove air periodically.  The CS-2000 also has a built in pressure sensor to monitor the pressure/vacuum being generated by the Venus 2000.  This pressure/vacuum information can be used by a computer for additional analysis.

The third part of the third generation is the receiver guide.  The Venus 2000 maker does not offer a receiver guide, but for hands free operation the Venus 2000 needs some sort of guide to hold the receiver is proper alignment. The metal stand shown here has been further modified to interface with the CS-2000.