How to Control PC Parallel Port for Infrared Electronic Lock Project?

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#31 21665968 16 Jan 2013 15:28

Mark Harrington Mark Harrington

Anonymous

Post #31
21665968 16 Jan 2013 15:28

All the suggestions Ive made are free Even basic you can download for free from micosoft as well
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#32 21665969 16 Jan 2013 15:34

Mark Harrington Mark Harrington

Anonymous

Post #32
21665969 16 Jan 2013 15:34

Aah Eugene they dont tell you that Thats what we were getting all the time which is now making sence becuase also at the time I was finding strange files on my desktop which later on proved to be hacking my registry to get into my email account which The authorities catagorically denied and said Oh nothing to worry about Only I didnt believe them just as well I didnt as well so that might make sence of some of this
#33 21665970 16 Jan 2013 15:52

Mark Harrington Mark Harrington

Anonymous

Post #33
21665970 16 Jan 2013 15:52

I still dont have that in my registry I get to HKEY_LOCAL_MACHINE/SYSTEM/CONTROLSET001/SERVICES/parport/enum

No such key in parport or enum, missing any ideas

parameters missing. Not listed
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#34 21665971 16 Jan 2013 16:07

Eugene Lisovy Eugene Lisovy

Anonymous

Post #34
21665971 16 Jan 2013 16:07

You must create this value into the registry.
By default this value is absent.
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#35 21665972 16 Jan 2013 16:38

Mark Harrington Mark Harrington

Anonymous

Post #35
21665972 16 Jan 2013 16:38

No I think what you are refering to is windows xp 64 bit not 32 bit Ive just been reading up on same difficulties with arduino ref programmer not working on xp

Yes they mention this as you have but its for 64 bit that this entry exists for

Here is the link

http://arduino.cc/en/Hacking/Bootloader?from=Main.Bootloader

Here some further reading regard this problem I seem to recall trying something like this last time and had same problem many years ago hence why I gave up with this

See what you think

http://retired.beyondlogic.org/porttalk/porttalk.htm
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#36 21665973 16 Jan 2013 17:42

Mark Harrington Mark Harrington

Anonymous

Post #36
21665973 16 Jan 2013 17:42

You can imagine what this does to the Industry cant you Especially if you happen to be a student or simply trying to learn and you pass mark is dependant on getting your parrellel port to read and output a value

Fantastic isnt it In other words here is how we can prevent you from getting any further or passing your degree

Charming. ... ! ! !

Im just about to puy a schematic together and see if I can get it to work 15years later still not to worry thanks Eugene Third time lucky maybe
#37 21665974 17 Jan 2013 03:29

Steve Lawson Steve Lawson

Anonymous

Post #37
21665974 17 Jan 2013 03:29

Sure, totally safe, if no typos or other screw ups -- nobody is perfect ;)

In other words, better safe than sorry.
#38 21665975 17 Jan 2013 17:29

Mark Harrington Mark Harrington

Anonymous

Post #38
21665975 17 Jan 2013 17:29

I found some very interesting information for you tonight on java serial ports Which I thought might interest you Steve etc So I’m uploading some files plus the package which should make life that more interesting for you

By the way you can’t download this package from Sun or Oracle anymore took me some time to find this
It might be an idea to make a permanent link to this now Yes its still works A ok on XP 32 bit The linux interpretation is working I might try and sit down this year and rewrite this
#39 21665976 19 Jan 2013 03:17

George James George James

Anonymous

Post #39
21665976 19 Jan 2013 03:17

Thanks Mark, I have been reading a lot of stuffs on this, a lot of which don't make any sense at all, but am still reading, and if there is something I am sure of, it's that I am sure going to make it work, THANKS everybody I have found all suggestions really helpful
#40 21665977 19 Jan 2013 14:22

Mark Harrington Mark Harrington

Anonymous

Post #40
21665977 19 Jan 2013 14:22

Don’t worry James take your time read through some of it

Doesn’t matter if you don’t understand this from the word go Don’t expect too It took me nearly 15 years and I still struggle with this , nothing to be ashamed off

If someone’s thinks you a fool for asking a question bare in mind that for 5 minutes it may appear that people think this , but there after your are ten times the man that they are for asking and 100 times wiser than they will ever be

Read as much as you can take in what you can then ask questions about what you have read and what ever it is that you’ve understood People will be only to pleased to guide you if you are prepared to make that effort yourself
Create an account, log in here. You will receive points by participating in discussions.
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Topic summary

✨ The discussion addresses controlling PC parallel ports for an infrared electronic lock project. Key challenges include limited direct access to parallel ports on modern Windows OS (especially XP and later), requiring special drivers or registry modifications such as disabling LPT polling via the registry key "DisableWarmPoll". Many users report difficulties with parallel port interfacing due to OS restrictions and driver issues, leading to recommendations to use serial ports or USB interfaces instead. USB-to-serial or USB-to-TTL converters (e.g., FTDI chips, PL2303HX modules) are suggested as more reliable alternatives. Several tutorials and toolkits are referenced for parallel port interfacing, including resources at logix4u.net, beyondlogic.org, and eeweb.com. Programming options for GUI control include Visual Basic, Delphi, Tcl/Tk, Java (with native method calls), and C#. Some users recommend microcontroller-based solutions using PIC MCUs with RS232 level converters (MAX232C) or FTDI chips for USB communication. Registry editing advice includes backing up before changes and awareness of 32-bit vs 64-bit Windows differences. Additional ideas include integrating smart card readers, webcams, or Raspberry Pi for advanced control and networking. Overall, the consensus favors using serial or USB interfaces over direct parallel port control due to modern OS limitations and driver support challenges.

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How to Control PC Parallel Port for Infrared Electronic Lock Project?

FAQ

TL;DR: For desktop-controlled IR locks, skip legacy LPT and use USB‑to‑serial; Steve shared 5 example adapters and noted, “what you want is a USB to TTL.” [Elektroda, Steve Lawson, post #21665948]

Why it matters: This approach works on modern PCs, simplifies coding, and avoids brittle parallel‑port drivers—perfect for beginners building reliable locks.

Quick Facts

Windows NT/XP often blocks direct I/O to LPT without a helper driver or toolkit. [Elektroda, Mark Harrington, post #21665942]
XP tweak: Disable LPT warm polling via DisableWarmPoll=1 at the Parport\Parameters key (advanced users only). [Elektroda, Eugene Lisovy, post #21665964]
Direct port access toolkits exist for NT-like Windows and DOS tasks. [Elektroda, Eugene Lisovy, post #21665961]
Low-cost DIY USB‑to‑LPT bridge: AVR-based USB2LPT project with schematics. [Elektroda, Eugene Lisovy, post #21665966]
Beginner GUIs: Visual Basic, Delphi, and Tcl/Tk can drive a virtual COM port. [Elektroda, Steve Lawson, post #21665958]

How do I control a PC port for an infrared lock in 2025?

Use a USB‑to‑serial (USB‑to‑TTL/RS‑232) adapter and drive a microcontroller (e.g., PIC/AVR) that switches your IR transmitter/relay. This avoids fragile LPT access on modern OSes and gives you a stable virtual COM port for your app. Steve’s post lists multiple adapter options. [Elektroda, Steve Lawson, post #21665948]

Should I avoid the parallel (LPT) port for new builds?

Yes. LPT is phased out on new PCs and driver access is inconsistent on NT/XP and later. Engineers in the thread moved to serial or USB front ends because they "always work" across systems. That reliability matters for locks and safety. [Elektroda, Mark Harrington, post #21665942]

What exactly is a USB‑to‑TTL/USB‑to‑RS232 adapter?

It converts USB from your PC into a UART signal (TTL level or RS‑232 level) that microcontrollers understand. Common chipsets include FTDI; vendors like SparkFun, Adafruit, and Parallax sell ready modules. Your PC sees a COM port you can open from most languages. [Elektroda, Steve Lawson, post #21665948]

Quick 3‑step: how do I build a simple USB/serial front end for the lock?

Hardware: Pair an FTDI module or a MAX232 RS‑232 level shifter with a small MCU to drive your relay/IR LED.
Firmware: Parse simple bytes/ASCII over UART to toggle lock states.
PC app: Send commands from Java or C# over the virtual COM port. [Elektroda, Mark Harrington, post #21665956]

How can I access the LPT port on Windows XP/NT if I insist on using it?

Use a port‑access toolkit/driver designed for NT‑like systems to gain user‑mode I/O to LPT registers. This enables experiments or legacy hardware under controlled conditions, though it’s more brittle than USB‑serial. [Elektroda, Eugene Lisovy, post #21665961]

Is editing the Windows registry safe for LPT tweaks?

Treat it as risky. Back up the registry first. If something breaks, boot Safe Mode and restore. A single typo can derail your system. As Steve cautioned, "better safe than sorry." [Elektroda, Steve Lawson, post #21665965]

How do I disable Windows XP’s LPT polling and why would I?

DisableWarmPoll=1 under the Parport\Parameters key stops periodic LPT polling that can interfere with direct port experiments. This is an advanced change; document and back up before editing. [Elektroda, Eugene Lisovy, post #21665964]

Can a beginner build the GUI to lock/unlock?

Yes. Options include Visual Basic, Delphi, or Tcl/Tk. Each can open the adapter’s COM port and bind buttons to send bytes. Tcl/Tk is cross‑platform and approachable; VB offers a very friendly designer for quick results. [Elektroda, Steve Lawson, post #21665958]

What languages and tools did the thread suggest for the PC side?

Java, C#, VB, Delphi, and Tcl/Tk were suggested. Mark noted JDK7 was then current and highlighted cross‑platform benefits. Choose what you know; serial libraries exist for all. [Elektroda, Mark Harrington, post #21665956]

What’s FTDI, MAX232, LPT, and TTL in simple terms?

FTDI: USB‑UART bridge chips/modules. MAX232: converts TTL UART to RS‑232 levels. LPT: legacy 25‑pin parallel printer port. TTL: 5V/3.3V logic UART signal for MCUs. These terms appear across the suggested hardware paths. [Elektroda, Steve Lawson, post #21665948]

Is there a low‑cost DIY bridge if I must keep LPT hardware?

Yes. An AVR‑based USB2LPT project emulates a printer port over USB, useful for legacy devices when native LPT is unavailable. It includes schematics and firmware. [Elektroda, Eugene Lisovy, post #21665966]

Any beginner‑friendly learning resources or communities?

SparkFun tutorials and support forums are solid starting points. Follow a guided USB‑to‑serial example, then adapt it to send your lock commands. Ask questions as you hit roadblocks. [Elektroda, Steve Lawson, post #21665952]

Can I configure or test ports with HyperTerminal?

You can test serial communications with HyperTerminal by opening the virtual COM port and sending bytes to your MCU. It does not configure LPT, but it’s handy for serial debugging. [Elektroda, Aniruddh Mali, post #21665957]

What pitfalls should I expect on Windows XP and drivers?

Expect driver hurdles, 32‑bit vs 64‑bit confusion, and tools that work only in DOS/Win9x. Many gave up on LPT under XP and pivoted to serial/USB. Plan for that fallback early. [Elektroda, Mark Harrington, post #21665972]

Where can I read a primer on parallel ports?

Start with the tutorial linked in the thread. It explains LPT basics, signals, and interfacing concepts useful for understanding legacy control paths. [Elektroda, Eugene Lisovy, post #21665939]

Is Tcl/Tk still free for hobby use?

Yes. ActiveTcl offers a free Community edition with forum support, suitable for learning and small tools that talk to COM ports. [Elektroda, Steve Lawson, post #21665960]