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-
- The Analogue to Didital Converter project.
- ------------------------------------------
-
- Overview:-
- ----------
-
- This project will enable you to use the parallel port to input voltages
- from 0 to +5 Volts positive and display this voltage as a number in a test
- window. When built it will be used with other projects to measure all
- types of signals whether they be DC, AC, voltage, current, power etc..
- using the correct type of software. With some minor modifications this will
- be used to make an oscilloscope. The first unit was built on a prototype
- EuroCard and was hard wired on the underside of the card. This will be
- the device to be described, although I have drawn a board layout for you
- that is NOT to scale at all. There are no instructions on how to fit this
- unit into a box. This will give you a chance to modify a standard box,
- drill any holes, cut out any slots that may be required to finish the unit
- off and then finally label it.
-
- ----------------------------------------------------------------------------
-
- The Parts List:-
- ----------------
-
- For the first part of this project use the parts that are required for
- ~Circuit_1~ only. Do NOT fit R3, R4, RV2, ZD2 and SK1 at this point. I
- have included some suppliers references for the special items. The rest
- can be sourced from any supplier.
-
- ----------------------------------------------------------------------------
-
- The Construction Proper:-
- -------------------------
-
- 1) Do NOT trust any markings on the EuroCard, they may be wrong!!
- 2) Fit the 25 way ~D~ type plug to the EuroCard first. Check that the
- marking on the board at position ~1~ is ths SAME as pin ~1~ on the
- plug. If it is NOT the same then ignore all markings on the EuroCard.
- Fit this on to the NONE print side of the board.
- 3) Fit the IC socket so that pin ~1~ is facing the same way as pin ~1~ on
- the ~D~ type plug. Fit this on the NONE print side of the board.
- When these are fitted MARK with CARE pin ~1~ on BOTH sides of the board
- so that you know where they are when you start adding the other
- components. An error at this point WILL be catastrophic on power up.
-
- Fit these remaining items on the print side of the board:-
- ----------------------------------------------------------
-
- 4) Connect R2 from pin ~4~ to pin ~19~ on the IC holder.
- 5) Connect C1 from pin ~4~ to pin ~2~ on the IC holder.
- 6) Connect R1 from pin ~20~ to pin ~9~ on the IC holder.
- 7) Connect ZD1 from pin ~9~ to pin ~10~ on the IC holder, the BAND going
- to pin ~9~.
- 8) Hard wire the IC socket to the ~D~ type plug as follows:-
-
- IC1 PIN(S) TO PL1 PIN(S)
- ---------- ----------
- 3 CONTROL LINE 1
- 5 CONTROL LINE 10
- 20 +5V SUPPLY 14
- GROUND - 1,2,7,8,10 ------- CONNECT TOGETHER - 17,18,19,20,21,22,23,24,25
- 18 DATA LINE 0 2
- 17 DATA LINE 1 3
- 16 DATA LINE 2 4
- 15 DATA LINE 3 5
- 14 DATA LINE 4 6
- 13 DATA LINE 5 7
- 12 DATA LINE 6 8
- 11 DATA LINE 7 9
-
- 9) Connect a RED wire from pin ~14~ of PL1 to one outside tag of RV1.
- 10) Connect a BLACK wire from pin ~25~ of PL1 to the opposite oustide tag
- of RV1.
- 11) Connect a BLUE wire from pin ~6~ of the IC holder to the centre tag
- of RV1.
- 12) Plug the IC (IC1) into the holder, ensuring that pin ~1~ is in the
- correct position.
- 13) CHECK all of your work. RECHECK all of your work again. CHECK against
- the circuit diagram, ~Circuit_1~.
- 14) Check for short circuits, errors, faulty joints and components in the
- wrong place. Correct as required.
- 15) Remember... an error at this point could result in a failure of your
- computer when you power up.
- 16) Even a professional like myself has been known to make catastrophic
- errors when building prototype equipment.
- 17) When you are sure that you have constructed the A-D Converter properly
- you are now ready to connect to your computer.
-
- ----------------------------------------------------------------------------
-
- Testing the A-D Converter:-
- ---------------------------
-
- 1) Switch off the AMIGA.
- 2) Plug the A-D Converter board into the parallel port.
- 3) Boot up the AMIGA.
- 4) Start the ~Parallel_Test~ software. This will be a small window with
- a number between 0 and 255 showing.
- 5) Rotate the potentiometer RV1 in either direction and this number will
- change between a minimum of 0 to a maximum of 255. If you get this
- result then Well Done. Switch off the AMIGA and disconnect the A-D
- Converter. It is working correctly.
- 6) If you do NOT get this result switch of the AMIGA and disconnect the
- A-D Converter. RECHECK all of your work, repair as neccessary and retry
- 1) to 5).
-
- ----------------------------------------------------------------------------
-
- Finishing off the A-D Converter proper:-
- ----------------------------------------
-
- Parts List:-
- ------------
-
- You will now require the parts for ~Circuit_2~ to finish off this project.
-
- ----------------------------------------------------------------------------
-
- Wiring information part 2:-
- ---------------------------
-
- 1) Disconnect the RED wire from pin ~14~ of PL1.
- 2) Disconnect the BLACK wire from the tag of RV1. Do NOT disconnect this
- wire from pin ~25~ of PL1.
- 3) Disconnect the BLUE wire from pin ~6~ of the IC holder.
- 4) Connect ZD2 from pin ~6~ to pin ~8~ of the IC holder, the BAND going
- to pin ~6~.
- 5) Fit the preset variable resistor on the NONE print side of the board
- about 10 holes away from pin ~6~ of the IC holder.
- 6) Connect R3 from pin ~6~ of the IC holder to the centre tag of RV2.
- Use insulation sleeving as required.
- 7) Connect R4 from pin ~10~ of the IC holder to one of the outside tags
- of RV2. Use insulation sleeving as required.
- 8) Connect the opposite outside tag of RV2 to the inner conductor of a
- PHONO/RCA socket.
- 9) Connect the body of the PHONO/RCA socket to the remaining BLACK wire.
- 10) CHECK all of your modifications. RECHECK these modifications. CHECK
- against the circuit diagram, ~Circuit_2~.
- 11) If all is well then you are now ready to calibrate the A-D Converter.
- 12) You will require a new 1.5 Volt cell for calibration purposes.
-
- ----------------------------------------------------------------------------
-
- Calibrating the A-D Converter:-
- -------------------------------
-
- You WILL require a 1.5 Volt dry cell type ~R6~. I used an ~EVEREADY~
- RED body ~ULTRA PLUS~ type, although any ZINC/CHLORIDE type will probably
- be alright.
-
- 1) Do ~Testing the A-D Converter:-~ parts 1) to 4) first.
- 2) The reading in the window should now read 0 (flashing 1).
- 3) Connect the 1.5 Volt cell across the RCA input of the A-D Converter
- using the previously made test lead from the Stereo LF Audio Function
- Generator project (Project5), positive to probe tip.
- 4) Adjust RV2 to give a value of 85 (flashing 86) in the window.
- 5) If all is well then you now have a simple 0 to +5 Volt DC voltmeter.
- 6) Run the ~VoltMeter~ software to start using the A-D Converter proper.
-
- ----------------------------------------------------------------------------
-
- Volt Meter Specifications:-
- ---------------------------
-
- Voltage Range.......................... 0 to +5 Volts.
- Resolution............................. 20 mV.
- Accuracy............................... + or - 5% of full scale.
- Input resistance....................... 20 KilOhms.
- Sensitivity............................ 4 KilOhms/Volt.
- Test lead(s)........................... Use ~Project5~ test lead.
-
- WARNING:-
- ---------
-
- 1) DO NOT USE ON VOLTAGES GREATER THAN +12 VOLTS.
- 2) DO NOT TRY TO MEASURE NEGATIVE VOLTAGES AT ALL.
- 3) ANY ATTEMPT TO DO EITHER OF THE ABOVE MAY RESULT IN DAMAGE TO THE
- BOARD AND/OR THE COMPUTER.
- 4) ANY VOLTAGES GREATER THAN +5.1 VOLTS WILL LIMIT TO +5.1 ON THE DISPLAY.
-
- ----------------------------------------------------------------------------
-
- And finally:-
- -------------
-
- This circuit board will be modified at a much later date for future
- designs. However it is good for most of the projects to come.
- There is an image of 320x200xHAM of my origonal prototype in this drawer.
- It is called ~Prototype_Board.ham~. You will require some type of ~HAM~
- viewing software to see it. I did not bother to write one as this image
- is unimportant to the overall package.
-
- ----------------------------------------------------------------------------
-
- Mr Barry Walker,
- 70 King George Road,
- Loughborough,
- Leicestershire,
- LE11 2PA,
- England.
-
- Email to:-
-
- 106161.3245@compuserve.com
- or
- wisecracker@tesco.net
-
- BYE.....
-
- ----------------------------------------------------------------------------
-