Details at: http://www.instructables.com/id/Simple-PC-oscilliscope/
This blog is for sharing information on computers, including but not limited to, programming, software, graphics, e-commerce, and everything that a geek, nerd, or dweeb can figure out to do on a computer. Mission Statement: To help the geek impaired with humanity computer related information, so none shall need suffer in front of the computer anymore.
Thursday, May 23, 2013
Easy PC oscilliscope
Just a beginner at electronics. Before you spend a lot bucks on equipment, check out this free pc ocilliscope:
Details at: http://www.instructables.com/id/Simple-PC-oscilliscope/
Details at: http://www.instructables.com/id/Simple-PC-oscilliscope/
Tuesday, May 21, 2013
Mom's autoharp.
Mom use to have an autoharp. She would play it once in a while. Kind of missed that old thing. Did not want to go out and purchase one. Saw a minimal bash script to let a linux box with sound emulate an autoharp. I modified that script to do a bit more. It only has a few chords, but it is the most I will need for a while. Working on a super version,
Just like a regular autoharp, all you have to do is press a key for the chord sounding.
Here is the source code that you can cut and paste into your favorite linux editor.
#!/bin/bash
#
# Script to emulate an autoharp.
#
while :
do
clear
echo "************************"
echo "* Mom's autoharp *"
echo "************************"
echo "* [1] C major *"
echo "* [2] A minor *"
echo "* [3] G major 7th *"
echo "* [4] F major *"
echo "* [5] D minor *"
echo "* [6] E minor *"
echo "* [7] E major 7th *"
echo "* [8] A major 7th *"
echo "* [9] C major 7th *"
echo "* [+] D major 7th *"
echo "* [-] G major *"
echo "* *"
echo "* [0] Exit/Stop *"
echo "************************"
echo
echo "Enter your menu choice [1-9, +, - or 0]: "
read -n 1 yourch
case $yourch in
1) play -n synth pl C2 pl E2 pl G2 pl C3 pl E3 pl G3 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
2) play -n synth pl A2 pl C2 pl E2 pl A3 pl C3 pl E3 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
3) play -n synth pl G2 pl B2 pl D2 pl F4 pl G3 pl B3 pl D3 pl F4 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
4) play -n synth pl F2 pl A2 pl C2 pl F3 pl A3 pl C3 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
5) play -n synth pl D2 pl F2 pl A2 pl D3 pl A3 pl F4 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
6) play -n synth pl E2 pl G2 pl B2 pl E3 pl B3 pl G4 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
7) play -n synth pl E2 pl G#2 pl B2 pl D2 pl E3 pl B3 pl G#4 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
8) play -n synth pl A2 pl C#2 pl E2 pl G2 pl A3 pl C#3 pl E3 pl G3 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
9) play -n synth pl C2 pl E2 pl G2 pl A#2 pl C3 pl E3 pl G3 pl A#3 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
+) play -n synth pl D2 pl F#2 pl A2 pl C3 pl D3 pl F#3 pl A3 pl C4 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
-) play -n synth pl G2 pl B2 pl D2 pl G3 pl B3 pl D3 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
0) exit 0;;
*) echo "Oopps!!! Please select choice 1,2,3,4,5,6,7,8,9,-, or +"
echo "Press Enter to continue. . ." ; read ;;
esac
done
Here is the source code that you can cut and paste into your favorite linux editor.
#!/bin/bash
#
# Script to emulate an autoharp.
#
while :
do
clear
echo "************************"
echo "* Mom's autoharp *"
echo "************************"
echo "* [1] C major *"
echo "* [2] A minor *"
echo "* [3] G major 7th *"
echo "* [4] F major *"
echo "* [5] D minor *"
echo "* [6] E minor *"
echo "* [7] E major 7th *"
echo "* [8] A major 7th *"
echo "* [9] C major 7th *"
echo "* [+] D major 7th *"
echo "* [-] G major *"
echo "* *"
echo "* [0] Exit/Stop *"
echo "************************"
echo
echo "Enter your menu choice [1-9, +, - or 0]: "
read -n 1 yourch
case $yourch in
1) play -n synth pl C2 pl E2 pl G2 pl C3 pl E3 pl G3 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
2) play -n synth pl A2 pl C2 pl E2 pl A3 pl C3 pl E3 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
3) play -n synth pl G2 pl B2 pl D2 pl F4 pl G3 pl B3 pl D3 pl F4 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
4) play -n synth pl F2 pl A2 pl C2 pl F3 pl A3 pl C3 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
5) play -n synth pl D2 pl F2 pl A2 pl D3 pl A3 pl F4 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
6) play -n synth pl E2 pl G2 pl B2 pl E3 pl B3 pl G4 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
7) play -n synth pl E2 pl G#2 pl B2 pl D2 pl E3 pl B3 pl G#4 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
8) play -n synth pl A2 pl C#2 pl E2 pl G2 pl A3 pl C#3 pl E3 pl G3 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
9) play -n synth pl C2 pl E2 pl G2 pl A#2 pl C3 pl E3 pl G3 pl A#3 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
+) play -n synth pl D2 pl F#2 pl A2 pl C3 pl D3 pl F#3 pl A3 pl C4 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
-) play -n synth pl G2 pl B2 pl D2 pl G3 pl B3 pl D3 delay 0 .05 .1 .15 .2 .25 remix - fade 0 1.5 .1 norm -1 ;;
0) exit 0;;
*) echo "Oopps!!! Please select choice 1,2,3,4,5,6,7,8,9,-, or +"
echo "Press Enter to continue. . ." ; read ;;
esac
done
Powering the Raspberry Pi.
Warning:
Do this at your own risk. We will not be responcible for any or all issues. Chances of electrocution causing death can occur. Get a professional to help before you start this project if you are even the least bit unsure.
Wanted to make a Raspberry Pi where I could have several units in one case. Putting several power supplies in one box seemed like a mess. Instead I decided to use an old "AT" (not atx) power supply. I did not want to cut up the cable from the power supply. I looked for a dead motherboard in the junk box. There was one! Now, had to get out the old heat fun (used for paint removal. Most "AT" motherboards are attached to the pc like this:
But if you have a dead motherboard it will not need the Power supply header anymore. So the mother board looked like this:
Now we want to add heat to the back side of the motherboard to release the header. Be careful as it is HOT. Solder could come flying and burn you. Wear protective clothing. Then once the header is free and cooled, it should look like this:
Ahh, free parts!! So now I can use the header with the Raspberrty Pi once I have soldered some wires to the header. PC Power supply must be turned off and disconnected from wall power while soldering. I.e solder the header disconnected from anything. Hint: Be sure to also use a glue gun to seal the solder connections so nothing can get shorted out.
You will need a pinout listing for that particular power supply you want to use. (Varying power supplies are not all the same when it comes to the pinouts!!)
This power supply only uses two of the three connectors. But what we need is a +5v (usually red) and a ground (usually black) to power the Raspberry Pi. So we could eventually power up to four units. The disk drive cables could aso be used, but we let them be for drives we could attach to the Raspberry Pi.
Do this at your own risk. We will not be responcible for any or all issues. Chances of electrocution causing death can occur. Get a professional to help before you start this project if you are even the least bit unsure.
Wanted to make a Raspberry Pi where I could have several units in one case. Putting several power supplies in one box seemed like a mess. Instead I decided to use an old "AT" (not atx) power supply. I did not want to cut up the cable from the power supply. I looked for a dead motherboard in the junk box. There was one! Now, had to get out the old heat fun (used for paint removal. Most "AT" motherboards are attached to the pc like this:
But if you have a dead motherboard it will not need the Power supply header anymore. So the mother board looked like this:
Now we want to add heat to the back side of the motherboard to release the header. Be careful as it is HOT. Solder could come flying and burn you. Wear protective clothing. Then once the header is free and cooled, it should look like this:
Ahh, free parts!! So now I can use the header with the Raspberrty Pi once I have soldered some wires to the header. PC Power supply must be turned off and disconnected from wall power while soldering. I.e solder the header disconnected from anything. Hint: Be sure to also use a glue gun to seal the solder connections so nothing can get shorted out.
You will need a pinout listing for that particular power supply you want to use. (Varying power supplies are not all the same when it comes to the pinouts!!)
This power supply only uses two of the three connectors. But what we need is a +5v (usually red) and a ground (usually black) to power the Raspberry Pi. So we could eventually power up to four units. The disk drive cables could aso be used, but we let them be for drives we could attach to the Raspberry Pi.
Friday, May 17, 2013
Soldering iron: a tech's best friend.
A soldering iron can be a tech's best friend. You never know when you need to repair an electrical connection. You can actually do a whole lot more, You can rescue parts for reuse. You can build your own simple test equipment. You can even build your own projects. You do not have to get a fancy soldering iron at first, but later as you gain experience, You may certainly want one. You also will want to learn about electronic symbols so that you can understand at least simple schematics.
The second project was to make a polarity tester. I wanted to know which side was positive and which was negative. Two leds (resitors if needed) and test leads from a dead volt/ohm meter was all that was needed here. If the red lead was connected to the plus or positive side of a connection (black lead should be connected to ground) the the top led would light. If the wiring were reversed then the other led would light. Great for testing diodes to see which way the should be conneccted to a circuit. You can als test low voltage batteries to see which is the plus (+) and negative (-) sides.
One of the first pieces of test equipment I ever made was a continuity tester. What is that? it is a tool to see whether a wire cam make a complete circuit. There are no breaks in the wire. Most of what I do is low voltage, so parts are not that critical. To make the continuity tester, I rescued a battery holder (from the motherboard) and an led from a dead computer. Saved a few bucks right there. So a soldering iron can get you free parts! The continuity tester is just a battery connected to a light bulb or the like.
The second project was to make a polarity tester. I wanted to know which side was positive and which was negative. Two leds (resitors if needed) and test leads from a dead volt/ohm meter was all that was needed here. If the red lead was connected to the plus or positive side of a connection (black lead should be connected to ground) the the top led would light. If the wiring were reversed then the other led would light. Great for testing diodes to see which way the should be conneccted to a circuit. You can als test low voltage batteries to see which is the plus (+) and negative (-) sides.
So far that is pretty simple stuff. Logic testers at one time were very expensive. Now you can get them pretty cheap at your local electronic store. Logic tester is sort of a simplified voltmeter that can only test for five and zero volts. With digital electronics that is all you need to test. For example, you may want to see if a parallel port is sending a signal on a particular wire. Maybe there is a break in one wire of the cable. You can test each line or wire individually for the result. We like to interface or connect electronic projects to the parallel port. You could also use this for the Arduino, Raspberry Pi. or any device that has a standard digital output. For example, I have and led connected to one of the digital ouput lines of the parallel port. For some reason if the led connected to the parallel port data line is not lighting up when it is supposed to. The logic tester can determine if the wire is outputing the 5 volts to light the led. If not it may be a software or programming problem. You then have to adjust the software. If you are getting the 5 volts, then the led may be faulty.
As I said earlier, logic testers even simple ones were not inexpensive. Found a magazine article that had a circuit to build your own. That meant for a few dollars for a few parts, you could have a logic tester instead of paying many dollars for one from and electronics store. I have since bought logic tester, but I still end up using the one i soldered together from the magazine article. Now you can find a zillion electronic circuits for the web that you can build (aka solder together). More info on the parallel port digital outputs at: http://www.instructables.com/id/No-solder-parallel-port-break-out/
You can use a logic IC (integrated circuit) or you can use discrete electronc parts (transistors and etc,) to also build a logic tester. Actuall you can get the parts you need from an flourescent light bulb for free, You have to be extra careful in doing that though.
Anyway, even with these three (fairly) simple projects, you can have some pretty neat testing tools on the cheap. You will volunteer to take old and or dead electronics from friends or whomever. As you can rescue all kinds of parts for free and save yourself lots of money. The soldering iron will pay for itself in no time at all. Or as they say, the more you know.....
Wednesday, May 15, 2013
Listen up industry,
Was not so long ago that when you bought a piece of software, you had to agree to the license, The license was sealed in the package the software came in. To furthermore complicate the sale, written on the outside of the package had a notice that if you opened the package it was not returnable. These were known as shrink wrap agreements. The public who thought this was unreasonable quit purchasing software. The industry claimed it was because people were illegally copying the software. Though that might have been partially true. The real reason for the sales slump was that you could get what was known as freeware that in a lot of cases was as good as the commercial products. Freeware did not have shrinkwrap agreements. The public took the industry to court and had the shrinkwrap agreements invalidated and even made illegal in a way.
At the same time, software known as word processors (aka electronic typewriters) were very popular software. The only problem was that if you created a document in Word Perfect, it would not work in say Microsoft Word. Companies. The public cried out for some compatability. The Software vendors vowed not to have compatability. This kind of killed that market also. Then I forget which one, but they started to add compatability in their software. Sales for their product rose. The other software companies relented and even marketed how they were compatible with their competitors. Why did industry not want to serve the best for their users until they were forced into it?
Now to present day, where if you purchase any hardware or software, In some cases, you must agree not to modify the hardware or software or risk going to prison for doing so because you are violating some random alleged software patent or copyright. Seems what it comes down to is you really do not own the product. Huh? Do not believe me. Read the fine print of what you have purchased lately. Pretty much as bad as the shrink wrap agreements.
To make things even more complicated. a certain company from Redmond Washing allegedly bullied makers of computers to add what is known as UEFI as part of the system. That means that company from Redmond Washington can allegedly control your computer at their whim. You still own your computer?. The uefi was allegedly included so that you will be more protected from security issues such as viruses, software piracy, and the like. So far only the systems using the Redmond Washinton software needs this quick fix. Most intelligent people in the industry call it a joke.
Other operating systems have to license use of the uefi software. Linux being one of them. Linux, BSD, and etc has no use for uefi for the most part. There are a few hardware manufacturers who do make equipment without the uefi, but expect to pay a premium. The uefi for the most part will not be retrofitted to older equipment. (God Forbid!). It has been rumored the real reason that uefi was used to try to lock out open operating systems such as Linux in a competition limiting move by a company that has been allegedly adjudicated a monopoly already on two continents.
Like in the days of the shrinkwrap agreements, the industry is complaing sales are down and is doomed. Maybe if the uefi was not forced into the hardware of new machines, sales would be dramatically higher. Apparently the industry has not learned the lessons of the shrinkwrap days, You try to control your customer and they will seek business elsewhere.
Again we have open source to replace freeware. I prefer open source as it allows me to use older hardware and software a bit longer. Maybe the industry will get a hint by the time I need a newer system. Also, why maybe many people are not purchasing new systems. If it ain't broke, don't fix it. Are you listening industry?
At the same time, software known as word processors (aka electronic typewriters) were very popular software. The only problem was that if you created a document in Word Perfect, it would not work in say Microsoft Word. Companies. The public cried out for some compatability. The Software vendors vowed not to have compatability. This kind of killed that market also. Then I forget which one, but they started to add compatability in their software. Sales for their product rose. The other software companies relented and even marketed how they were compatible with their competitors. Why did industry not want to serve the best for their users until they were forced into it?
Now to present day, where if you purchase any hardware or software, In some cases, you must agree not to modify the hardware or software or risk going to prison for doing so because you are violating some random alleged software patent or copyright. Seems what it comes down to is you really do not own the product. Huh? Do not believe me. Read the fine print of what you have purchased lately. Pretty much as bad as the shrink wrap agreements.
To make things even more complicated. a certain company from Redmond Washing allegedly bullied makers of computers to add what is known as UEFI as part of the system. That means that company from Redmond Washington can allegedly control your computer at their whim. You still own your computer?. The uefi was allegedly included so that you will be more protected from security issues such as viruses, software piracy, and the like. So far only the systems using the Redmond Washinton software needs this quick fix. Most intelligent people in the industry call it a joke.
Other operating systems have to license use of the uefi software. Linux being one of them. Linux, BSD, and etc has no use for uefi for the most part. There are a few hardware manufacturers who do make equipment without the uefi, but expect to pay a premium. The uefi for the most part will not be retrofitted to older equipment. (God Forbid!). It has been rumored the real reason that uefi was used to try to lock out open operating systems such as Linux in a competition limiting move by a company that has been allegedly adjudicated a monopoly already on two continents.
Like in the days of the shrinkwrap agreements, the industry is complaing sales are down and is doomed. Maybe if the uefi was not forced into the hardware of new machines, sales would be dramatically higher. Apparently the industry has not learned the lessons of the shrinkwrap days, You try to control your customer and they will seek business elsewhere.
Again we have open source to replace freeware. I prefer open source as it allows me to use older hardware and software a bit longer. Maybe the industry will get a hint by the time I need a newer system. Also, why maybe many people are not purchasing new systems. If it ain't broke, don't fix it. Are you listening industry?
Saturday, April 27, 2013
The Ups: a thought or two.
A Ups short for interuptable power supply is to condition electricity for the equipment connected to the unit. Usually not all lines are used for that. Some of the power receptacles (where you plug in things) can be used for surge protection only. Usually the conditioned power receptacles will say they are for using battery backup and surge protection.
Since I mentioned the unit is for line conditioning, the ups will smooth out or clean the power coming in the the devices the ups protects. It also should protect against extreme situations such power surges and brownouts.
Most people know about power surges, such a protection against such dangers as lightning strikes. Generally that is true if the lightning strike is not a direct hit to your power lines. Some electricity companies will install special surge protection on a home or building making it not usually necessary to have to use surge protectors in the building.
What a lot of people do not know about is brownouts. Sometimes this is called the silent killer of equipment. Surge protection will not help you in protecting from the brownouts. Brownouts can be more problematic than blackouts to delicate electronic equipment in some cases. Brownouts are defined as extended periods of voltage drop or sag coming from the power grid. In brownout conditions, most devices will continue to run, but with unexpected errors and possible long term damage to components. Brownouts can occur at the utility level like blackouts, but in many cases they can also occur within your building’s electrical grid, when a large local load is applied.
In a brownout, power supplies need to draw more current to compensate for the lower supply voltage, which is very stressful for transistors, wires, diodes, etc. They also become less efficient, which makes them draw even more current, aggravating the problem.
The ups obviously has a big job to do. There are actually two basic types of ups's. One unit uses line power till the power goes out and then the battery takes over. The switching from the line power to the battery can leave a short time when equipment connected to the unit has a mini blackout which can cause problems for really sensitive equipment. Plus the part of the system that does the switching will eventually wear out.
The second type of ups has power always coming from the battery via an inverter . The line power via a power regulator keeps the battery charged as needed. In this case, no real switching needs to be done. That is an over simplication, but the power will or should be rock solid. Generally these types of ups' are more expensive.
Given you just a thimble full lof information. You need to check out any ups that you might want to use in detail. But at least you have a bit of information to start with.
----------------------------------------------------------
Update: Interface from rs232 To apc cable if you do not have usb on your ups for use with the Powerchute software..
You will also need a special adapter if you do not want to do any soldering. And a DB9 male to male gender changer may also be needed.
Since I mentioned the unit is for line conditioning, the ups will smooth out or clean the power coming in the the devices the ups protects. It also should protect against extreme situations such power surges and brownouts.
Most people know about power surges, such a protection against such dangers as lightning strikes. Generally that is true if the lightning strike is not a direct hit to your power lines. Some electricity companies will install special surge protection on a home or building making it not usually necessary to have to use surge protectors in the building.
What a lot of people do not know about is brownouts. Sometimes this is called the silent killer of equipment. Surge protection will not help you in protecting from the brownouts. Brownouts can be more problematic than blackouts to delicate electronic equipment in some cases. Brownouts are defined as extended periods of voltage drop or sag coming from the power grid. In brownout conditions, most devices will continue to run, but with unexpected errors and possible long term damage to components. Brownouts can occur at the utility level like blackouts, but in many cases they can also occur within your building’s electrical grid, when a large local load is applied.
In a brownout, power supplies need to draw more current to compensate for the lower supply voltage, which is very stressful for transistors, wires, diodes, etc. They also become less efficient, which makes them draw even more current, aggravating the problem.
The ups obviously has a big job to do. There are actually two basic types of ups's. One unit uses line power till the power goes out and then the battery takes over. The switching from the line power to the battery can leave a short time when equipment connected to the unit has a mini blackout which can cause problems for really sensitive equipment. Plus the part of the system that does the switching will eventually wear out.
The second type of ups has power always coming from the battery via an inverter . The line power via a power regulator keeps the battery charged as needed. In this case, no real switching needs to be done. That is an over simplication, but the power will or should be rock solid. Generally these types of ups' are more expensive.
Given you just a thimble full lof information. You need to check out any ups that you might want to use in detail. But at least you have a bit of information to start with.
----------------------------------------------------------
Update: Interface from rs232 To apc cable if you do not have usb on your ups for use with the Powerchute software..
Adapter cable for the APC rj45-rs232 cable
The jack in the UPS may be easily use a 8 pin RJ45 connector. It is easy to construct the cable by cutting off one end of a standard RJ45-8 ethernet cable and wiring the other end (four wires) into a standard DB9F female serial port connector. (Try these pin-outs at your own risk.)
| PC Signal | PC pin | UPS Pin | UPS signal |
|---|---|---|---|
| RxD | 2 | 2 | TxD |
| TxD | 3 | 8 | RxD |
| GND | 5 | 7 | Ground |
| FG | Shield | 4 | Frame Ground |
You will also need a special adapter if you do not want to do any soldering. And a DB9 male to male gender changer may also be needed.
Tuesday, March 26, 2013
Portable podium
Always thinking of new ways to use a tripod. Earlier we made an adapter to allow a tripod to be a camera holder. Then I thought, why not make a portable lecturn. From the spare wood pile, simple enough as you just needed a rectangle wooden base with a small strip of wood as a lower paper stop.
Actually, you do need a special part called a 1/4 inch tee nut so it can be connected to the tripod. You can get them for about two for a dollar at the local hardware store.
Still think this setup is not that stable and would be hesitant to use it to hold any computing device, but then you can always live dangerously.
Poor man's stain (coat of tea and then vinegar that had steel wool steeping it it overnight.)
later.
Actually, you do need a special part called a 1/4 inch tee nut so it can be connected to the tripod. You can get them for about two for a dollar at the local hardware store.
Still think this setup is not that stable and would be hesitant to use it to hold any computing device, but then you can always live dangerously.
Poor man's stain (coat of tea and then vinegar that had steel wool steeping it it overnight.)
later.
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