Electronics, for fun - Some ideas for electronic hobby... and work
On this circuit there are eight DC power switch you can open or close through PC parallel port: you can use it to drive two unipolar stepper motor or eight electric light bulb or DC motors.
Digital interface to PC uses optocouplers for safety reasons and you can connect up to six circuits to a single LPT, driving up to twelve step motors or 48 bulb: see iso-buffer for an in deep description.
You can find in this page a sample code for Windows based on VVIO project
Circuit power supply should be from 14 to 50V. Maximum single switch current is five ampere if you use IRF540 but circuit can handle 10 A maximum for all switch. If you use logic level MOS, you can use power supply down to 7 V.
If your load is highly inductive, like motors, care should be used in diodes choice: they should be "fast recovery time" type and capable to sink load peak current. If you haven't any high speed diode, best to use slow 1N4001 then none.
C5 best choice is low ESR type but generic type should be right. Note you need high voltage type!
| C1 | 22 uF - 63 Vl - Electrolytic |
| C2,C3 | 220 nF |
| C4 | 10 uF - Electrolytic or tantalum |
| C5 | 1000 uF - 63 Vl - Electrolytic |
| D1,D2,D3,D4,D5,D6,D7,D8 | High speed diode (see text) |
| ISO1,ISO2,ISO3 | 6N135 - Optocoupler |
| JP1,JP2 | 5 poles connector, 5mm |
| JP3 | 5x2 poles connector, 5mm 2.54 mm |
| J1 | 2 poles connector, 5mm |
| Q1,Q2,Q3,Q4,Q5,Q6,Q7,Q8 | IRF540 - Power MOS |
| R1,R3,R5 | 180 ohm |
| R2,R4,R6 | 4k7 |
| R7 | 100 ohm |
| R8 | 220 ohm |
| R9 | 1k8 |
| U1 | CD4094B - 8-bit shift register/latch |
| U2 | LM317HV - Linear high voltage regulator |
If power supply is under 30V, capacitor voltage should be lowered and you can use a "normal" LM317.
The pcb is a double layer but I have not used any plated holes; it is necessary to insert some small wire in order to connect the two sides of the printed circuit and, for some components, use the "double-layer soldering" technique.
In order to avoid difficulty soldering on top layer, best way is to use the following order:
If you see PCB top layer, you can't see a lot of connection... so you can do a single layer PCB and add some "flying" wire
Software, schematic and PCB will be found in unipolar.tgz file
| licenza | License |
| schematic.pdf | Circuit schematic, in pdf format |
| top.pdf | Component pcb side, in pdf format |
| bottom.pdf | Solder pcb side, in pdf format |
| assembly.pdf | Components layout, in pdf format |
| LW_CVI | Software for windows: LabWindows/CVI |
To build this circuits you need:
If you need to drive a bipolar step motor, you can see Micro-step driver design.
Step Driver - Version 1.0 - August 2003
Copyright © 2003, VincenzoV.net
You need to read the license before to use this product
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You will find the original copy of this document on http://www.vincenzov.net.
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