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This thing is really good! I don't get any money for this link (but I wouldn't mind).

Big Robo's circuits:

Schmitt Trigger:
This is really the only thing left from Big Robo, that's worth to publish.
With poti R1, R3 you can determine, at which voltage level the trigger output goes high. R2 and R4 determine the threshold for low output. Jumper J3 - J7 are measuring points for the voltage levels. The circuit works on TTL (5V). If you need higher voltages use a CMOS version of the 7400.

Nutbot's circuits:

H-Bridge (V2.0):
Used for controlling Nutbot's fischertechnik motors. Use JP3 for power supply (up to 15V). JP2 is for the motor. On JP1, Pin 3 says in which direction the motor should rotate. If you want, you can use Pin 4 for stopping the motor (remove the bridge JP4). I used two zener diodes, mounted at the motor, for limiting the spikes, when switching off. The diodes are put together in reverse direction, so they block in both directions. Spikes are many times over the operating voltage, so one of the diodes breaks through and cuts it. The break through voltage should be higher than the operating voltage, because this breaking starts a little below that point.

Nutbot's main board:
The board is for a ST6265 MCU from ST Microelectronics.
The voltage regulator IC5 allows input from 7-36V. It's not very efficient to use such regulators, because they need an input, that is 2V higher than the output, and, whats more problematic, they turn the voltage (more precise: voltage * current2), that is too much, into heat.
All I/O-Pins are connected to plugs, where all module are plugged in. The IR-detector (SL8) does not exist. You can take Philip's sensor, but the connector must be adapted.
SL4 and SL5 are for the LCD-module. Take it from Philip.
The zip-file below, contains the main board and the increment detector.

Increment detector:
It delivers feedback to the MCU, about the way, that the robot has moved. The increment wheel is mounted on the axles. Every dark - light change is detected as one tic. The best way to create the pattern is using a CAD program. Print the pattern with a laser printer onto a foil. Ink-jet print-outs may not work, the black ink is invisible for IR-beams.
The schematic is included in the main board file, above.
Software Nutbots Firmware:
Really nice spaghetti code. O.k. this was my first assembler project, and it works stable. The watchdog is disabled, to uncover any error.
It's GPL software.

Terence's circuits:

Terence's main board:
Huh - should I explain all this...?
The really complicated things are the modified servos. You can find a very good description, how to hack a servo at Hacking a Servo by Kevin Ross.doc
Additionally I added increment wheels inside the servos. There is no description, how I did it at the moment. It will follow, but I don't know when (sorry).
You also need the LCD-Driver, IR-Sender and Receiver. Take it from Philip (improved sender).
Maybe, that the servo inputs don't work. I added transistors in Philip's schematic. They are also needed here.


Software Terence's Firmware:
It's GPL software.

Philip's circuits:

Philip's main board:
I'm still working on that robot. This causes, some unconvenience.
In principle it's the same as Terence's board. The servo input comes now over transistors. Have a look at R10, looks like a mistake in the wiring.
The board needs to be rebuilt, because I added some parts and didn't make a new board yet.
Problems of the board: The wires from the voltage input (JP11) to the servos (JP4 + JP5) are too small and too far from each other. I will correct this in the next version.

The board contains the same schematic twice. The square wave, sent by the IR-sender is detected by the LPT80A (T1, T2). A NE567 demodulates the signal and activates its open drain output (Pin 8), if the received frequency is the same as the programmed (R2, C1 and R7, C8).
The board works fine and is stable.

Maxim's ICM 7242PA is a one-chip-solution of a square wave generator. The frequency is determined by R9 + C1. The transistor array inverts and amplifies the signal and brings it to three connectors, to which the IR-LEDs are connected. The resistors R6 - R8 need to be adjusted to the LED. At the moment I'm trying a value of 68 ohms with a VX301 IR-LED.
The sending can be inhibited by pulling low Pin 3 of SL1. This is needed because the robot should distinguish between an obstacle and an foreign sender.
This board is brand new (I used an NE555 schematic before) and works stable.

LCD-Driver for a display unit:
When I started to develop software for Nutbot, I noticed very soon, that an output is necessary, where you can put debugging information. This circuit connects an LCD-module to the SPI of the microcontroller. A very fast 74HC164 is used, so that the SPI can be driven at full speed. You can use any display, compatible to the Hitachi HD44780 chips. Most of the dot matrix displays will fit. I use a 40x2 LCD, which I found in an old telephone.

Switching voltage regulator:
I have found it at Karl Lunt's page:
Please note, that the board has to be rebuilt!! The width of the current-driving wires is too small. This causes a voltage drop, if heavy load is put on (i.e.: the servos start working).

The construction plans of the robot:
The dxf-file can be opened with Q-Cad: It is a commercial project now. On some Linux distributions you may find an older, free version. Or, have a look for a free dxf-viewer.

Software Philips's Firmware:
The compile batches are written for windows (sorry), but there is no toolchain for Linux. You need the original ST assembler, which can be downloaded from: ST Microelectronics. The libraries controlling the hardware run fine, but there are still problems with the behaviors.
Assembler is not the right language for programming AI. Thats the reason, why I work on porting the software to atmel chips. The GNU-gcc supports that controllers and the whole toolchain runs under LINUX :-).



Simple Timer:
A timer schematic for an EPROM eraser. There's no board. The capacitor C1 and the poti determine the time-constant. There is a problem with large capacities and large resistor values. Maybe it works with a gold cap.
Because I use flash memory MCUs now, there was no need to develop it further. If you need information about building an eprom eraser, drop me a mail.