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Unanswered Questions





Ethernet Port Expansion 2019 Issue-3

My Internet router is located near our entertainment center in the family room. There are only four Ethernet ports on the router and I have five pieces of equipment that need to plug in. I also run a cable from the router to my home office (in the back of the house) that connects to an Ethernet switch that provides Internet to multiple computers, VOIP phones, as well as network connections for various printers.

At the router, I have to plug and unplug whatever equipment I want to use, since I don’t have enough ports to keep it all plugged in. Some devices can use the Wi-Fi, but performance is better and more reliable on the wired connections.

Questions:

  1. Can I add another switch at the router to expand the number of ports?
  2. What are the limitations/drawbacks on adding more switches to the network? (I currently have two in the office.)
  3. Is there a better way to do this?

#03193
Byron Rochefort
Fort Wayne, IN


Image Reverse 2019 Issue-3

I’m building a rear facing camera system for my car that displays the image on a 7” screen mounted on the dash. However, the image appears reversed horizontally. Is there a circuit to flip the image left to right so it would be correct from the perspective of the driver? Any ideas are appreciated.

#03192
Krystian Czarnecki
Lombard, IL


Troubleshooting Circuit Needed 2019 Issue-2

I’m looking for a circuit using a piezo buzzer, that I can hear from the room above the cellar. It will be connected to a Taco Heating Zone Valve on the boiler in the cellar for troubleshooting the thermostat when it goes on and off.

#3194
G Forcino
via email


SCSI Card Or Adapter Needed 2019 Issue-1

I have a bunch of old optical disks that have data archived from about 20 years ago that I would like to access. I found the stand-alone drive in a box of old computer junk, complete with the big SCSI cable. Problem is that I don’t have the computer anymore that has the SCSI card to plug it into, and don’t even know where to begin to look for one.

Is there something comparable that will work with a modern computer? An SCSI to USB adapter maybe? What about drivers? The old machine was probably Windows 98.

#1192
Mark Cisneros
Columbia, TN



Answers

I have a Win98 computer set up to read SCSI disc drives. It was a bear to create and find drivers for. I’m in Phoenix Arizona.

My next question is what software would be needed to read the data, is it just text? My setup was crated to be able to read and copy SCSI to sim cards, because of the lack of production of SCSI drives. I can currently copy from SCSI to sim cards if that would help. SCSI is old technology that is not really supported. If the data is important, I could probably read your drives and forward the data back in a usable format.

Let me know.

Antoinette Sides
via email

Adaptec made a USB 1.1 and a USB 2.0 SCSI to USB adapters; USB 1.1 M/N FX0C21902KL P/N 1861400; USB 2.0 M/N FX0A229005U P/N 1989100. I have one of each and they worked on every device I tried them on. Obviously the USB 2.0 is faster. I think the main drivers were Windows 98, but I can't recall for sure. I think I used them last under Windows XP.

Alexander Fisher
Galloway, OH

There are still PCI cards available for your SCSI drive, although they go by either GPIB or IEEE488 interface. National Instrument has both the cards and drivers (http://www.ni.com/en-us/shop/select/gpib-instrument-control-device). It would be difficult to connect the SCSI drive to the computer with a USB connection since the drive requires several control lines for proper access.

Lance Corey
Santa Ana, CA

I find some SCSI/USB adapters on eBay for around $170 to $300 each. I also find brand new SCSI/PCIe host adapters on Amazon for under $100. Either way, unless your cable is a Macintosh style cable (DB/25 to AMP50), you’ll also need a new cable. (For most of the PCIe host adapters, you’ll still need a new cable). What make and model are the optical disks? You may be better suited to pick up a used MO drive that’s SATA and use it on your current PC. Or with a SATA/USB adapter externally.

Ralph Phillips
Bossier City, LA


DC To AC 2019 Issue-1

I have a 100 amp 110 volt DC generator. I want to convert the output to 60-cycle AC. Does anyone have a schematic or info to build a converter? How much power loss can I expect in the final converted output? Thanks for any info.

#1191
Lucio Saunders
Indianapolis, IN


Devices/Software/Scheme For Wi-Fi Remote Control Using Smartphone 2019 Issue-2

There are a number of articles in the past issues of Nuts & Volts for a variety of ways to control devices in a home using a variety of control devices and schemes. However, none seem to have the combination of characteristics that I want. I would like to control a pair of simple low current AC sockets (ON/OFF) from my cell phone. I would like to use a combination of an existing app, a PIC style device (Ardunio or whatever), and a Wi-Fi module to connect it to my existing Wi-Fi. I do not see why a $100 hub should be needed. My present cell phone uses the Windows operating system, but I know that apps for it are scarce and I am willing to get an Android device. I’m stuck on finding the cell phone app and the Wi-Fi module. I would assume that I would have to write the appropriate code for the PIC device. I can interface the PIC with a relay, probably a solid state one. Any suggestions?

#3193
Edward Alciatore
Beaumont


Side Lights As Turn Signals - MG Auto 2019 Issue-2

My brother has an old MG that he likes tinkering with. He wants to use the side lights to indicate when the turn signal is on for drivers that are on either side of him. Normally, the side lights turn on and off with the headlights.

In his case — and to reduce peak power consumption to the blinker circuit — he would like the side lights to turn on when the signals are off, and vice versa (when the turn signal switch is turned on). Additionally, if the lights are on, the side lights should give priority to the turn signal, turning on and off, opposite to the signals in the front and rear, and returning to full on when the turn signal is not engaged.

I think the simplest way to do this would be with solid-state relays and the use of some logic gates (for each side). I have built hundreds of logic circuits, but have not really dabbled much in automotive applications. I know the electronics have their own temperature and performance specs and are noisy environments, not to mention the notoriously bad reputation that English cars have for electrics. Can you recommend a circuit for this application? (This car is a NEGATIVE chassis).

#3192
Patrick Gilmore
Amherst


Introducing A Time Delay Into RC Car Steering 2019 Issue-2

A local STEAM program is looking into using an RC car or truck to simulate operating a vehicle on the moon or other astronomical object. One big opportunity to excel is introducing a time delay (say five seconds) into the steering system to model the time required for radio to go signals to and from the vehicle. The first thought is to buffer the command string at the transmitter or receiver. Ideas, hints, suggestions?

#3191
Jon Caples
Parker, CO


Reset System For Cable From Both Computer And Cell Phone 2019 Issue-3

My cable system needs frequent resets. That means turn the power off to the cable box (router) and to my own WiFi router, wait 30 seconds, and turn the power back on. This is really aggravating when I am in the bedroom or the garage shop trying to watch streaming video on my TVs there and the routers are at the other end of the house.

I want to build a WiFi based system so I can activate a control to cycle the AC or DC power from anywhere in the house either via one of my computers or my cell phone. Now, my phone is a smart phone, but not a name brand like Apple. It’s a Nokia and uses the Windows operating system, so the available apps are somewhat limited.

So, I’ll need an app that will work there and one that will work on my desktop computer running Windows 10. I would like some ideas on how to proceed. I would think that I could base this on an Ardunio or other single board computer which could easily handle a 30 second time-out.

I can figure out the interface to the power relay, some local PB controls, and a display. But how do I handle the controls through the WiFi? I need advise on a WiFi interface and the apps that are needed to activate it.

#03191
Edward Alciatore
Beaumont


About Resistors November/December 2018

Could someone explain what pull-up and pull-down resistors are, when and how they’re used, and how to calculate their values?

#11187
Andy Dietrich
Dallas, TX

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