EAS designs & ideas

This area is dedicated to user submitted articles and design ideas. The circuits and projects listed in this area is a service provided by EAS to the robotics and electronics community.

If you would like to have something posted here, please contact us.

Electric Bikes

Iíve been tied up with electric bikes and scooters for the past few years. Here is a link to my creations. My favorite is this ebike I built for the trails from a Motobecane frame, many of the parts I had to CNC with our mill.

PCB Etchant Tank

A good article on how to make a pcb etchant tank with image by VKF


Running a PIC CPU core on a FPGA

HB circuits

Schematic showing the missing Handy Boards circuits. For those who want to add them to the Finger Board.

Run IC4 on FB

Bill Sherman did a nice write up on how to run IC4 on the Fingerboard. Thanks Bill.


Modified Interactive C version 4 pcode that will run on the Fingerboard. The start/stop button routine was removed so that programs will autorun when reset. No need to install the start and stop button circuits. This pcode requires version 4.30, older versions of IC4 will give a error. Replace the lib_hb_exp.frm file found in the \Interactive C 4\handyboard\ directory with this version. You can now use the built in IC4 downloader utility to upload the file to the FingerBoard. You can also rename the file with a .S19 extension and use any HC11 downloader utility instead. This pcode includes the SmoothPWM routine.

MiniDaq circuits

Schematic showing some interface circuits for the MiniDaq.


Use Minidaq to control up to 8 Dallas Semiconductor DS1621 digital thermometer, written by Richard Harazin

24 A/D input

Schematic showing how to add 24 more A/D inputs using multiplexers to the Finger Board.


HOWTO: R/C servo modification for 360 degree rotation.


The 2.86HB pcode version with Smooth PWM modified by EAS to compile under MS-DOS.


Application note on hooking up a EEPROM to the Finger Board SPI port. Requires Adobe Acrobat PDF.


Application note on hooking up our MiniDaq A/D unit to the Finger Board SPI port. Requires Adobe Acrobat PDF.


This is a icc11 (freeware version) library for the Finger Board (or Handy Board) with LCD print routine. The library was modified from the original Miniboard library written by Fred Martin. It is pretty basic but will get you started if you are interested in using icc11.

serial drivers

Interactive C 9600 and 2400 baud serial drivers using PORT D I/O pins.


The Handyboard version of the pcode modified so it will run on the Finger Board. The Start button routine was removed so programs will autostart when the processor is reset. The LCDbusy routine also removed so the Finger Board can run without a LCD display. This version of the pcode also includes the Smooth PWM motor drivers. For use with the Smooth PWM version of the lib_hb.c library.

Updated 11/24/98 This version now has the floating point divide error fix.

To save the s19 file, right click on your browser and do a "Save Target As..."


The above pcode assembly listing for compiling under Unix systems.


Here's faster version of the MiniDaq DLL library. The DLL A/D routine was rewritten to run up to 35% faster. On a 200Mhz Pentium, a little over 9000 samples/sec can be achieved. Because of the way the A/D routine was rewritten, digital output port 6 is no longer available. If you need to use digital output port 6, use the standard MiniDaq DLL library.


UserPort is a simple kernel mode driver for Windows NT/2000/XP that will give programs access to I/O ports. This makes it possible to access the hardware I/O ports directly under Windows NT/2000/XP just like 95/98/ME. Under XP, you may have to set the compatibility mode for the executable to "Windows 98" mode. We do not support Minidaq running on Windows NT/2000/XP operating systems due to using a 3rd party driver, however it does seem to run fine with the systems we have here in the lab.


Directio is another Windows NT/2000/XP driver that will give programs access to I/O ports. dvm_giveio.zip is an example VB6 program for our SpeedDaq A/D board that will use the giveio.sys driver to access the parallel port. You will need to download directio.zip and install the giveio.sys driver before using the demo.


Some example C and Visual Basic code to access a National Instruments AT-MIO-16 data acquistion card.


PIC 16F628 quadrature optical encoder to step/direction output source code. Useful for manual control of stepper motor drivers using a rotary encoder.


Some quadrature decoder examples in VHDL found on the net.


A person on the cad/cam/edm/dro CNC newsgroup requested a compiled version of the linistepper assembly code for the pic16f84A. I don't have a linistepper board so can't test the code but it compiles cleanly under mplab.


The Rug Warrior and Handyboard v2.81 pcode with Jon Howells' floating point divide error fix. This pcode is considered BETA. If you notice any problems, please email me at info@embeddedtronics.com.
For those who want to compile their own version of the pcode, here's the math library with the new FLTDIV routine. math11routines.asm

To save the s19 file, right click on your browser and do a "Save Target As..."

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