While the advent of devices like the AVR and PIC microcontrollers have enabled the hobbyist to implement their vision into a real world working piece of hardware, it has also become a substitute for a solid knowledge of digital circuits and design by some.
The digital circuit hobby designer has become a black box, embedded code designer, and may lack the rudimentary knowledge of digital hardware design. Donít get me wrong; there are many PIC and AVR users that do have a good digital design foundation, but use the embedded approach out of convenience. Often however; a budding hobbyist learns the ways of the black box art without much knowledge of digital design. The latter situation becomes apparent when a person inquires about building a divide by N circuit, and the response is often, ďUse a PICĒ. To me this seems silly when a simple logic device would suffice.
If a hardware engineer were to suggest such a solution for a production unit, he/she would be thrown
Taking on a web 2.0-3.0 approach, the new digital-diy.com site has launched and already getting over 500 hits a day (without google indexing?? must be somewhat alright then!)
Its the microcontroller thinktank of the internet, allowing registered users to submit content and collaborate with other members from all over the world.
Further more, why restrict the site to PIC micro controllers and 1 or 2 languages? The new digital-diy.com site supports all popular programming languages and micro controllers. We've started out with AVR's and PIC's, with support for Basic, C and Assembly.
If you can contribute to the site, please register a username and submit an article today!
Sometimes we think, "it is just an innocent relay", why add a freewheeling diode or some other snubber circuitry?
Well, take a look. I took those pics of a common 12V relay and a mechanical switch to toggle it.
I used a VC-6545, to measure. Storage mode and Norm. triggering.
This is the pure circuit, without any snubber:
Behold that you have a lot of spikes, the peak voltage is 284V, and the total "spiking" time, is about 150 Ķs.
Now just imagine a BC548 with those spikes across the collector (Vceo = 30V).
Or worst... A low voltage MOSFET would have its gate's oxide destroyed, if there was a series of relay switching events.
It is important to say that I was using a mechanical switch, so I'd have power loss on the contacts. With a transistor the spiking would have much more power. And more power
First Impressions of the Amscope SM-3TX Stereo Zoom Microscope
Iím sure there are many hobbyists and professionals out there working with very small electronics components who need a microscope. I have used a stereo scope for the last 20 years and could not function without one now that my vision is catching up with my age. But a microscope is a bit like a good RF signal generator, they are just so darn expensive to get a good one that you end up with something cheap and second rate or something very old (which might be just fine) or just do without. Thatís especially true for hobbyists or those new to the business. Well, we recently had need to buy one, but on a tight budget, and here is how it went.
To begin with, I decided I wanted more working room than my old scope, adequate optical quality, zoom feature, and smooth controls. I sought advice in scientific and electronic forums on what to buy. Commenters generally advised
The 7555Timer_Calc1. exe file requires the Visual Basic 5 or 6 runtime files. [free download from the web].
It is possible to select the 3 basic configurations for the 7555. Astable, Monostable, Astable Ver2 50% duty cycle.
The timing components can be changed to suit your application.
Enter: All resistor values in K ohms eg: 4.7 10 etc, capacitor values in micro Farads.
Note: The Visual Basic runtime files are often required for many web sourced programs.
It is recommended that you download the Datasheet for the device from www.datasheetarchive.com
Ensure that your designs are within the stated operating parameters of the device.
7th May 2010 Issue V1.2 Minor changes to display boxes
I often see the question asked "where do i find information about designing audio amps and such?"
Here is a list of resources i recommend if you want to learn about audio circuit design...
1) Audio Design information in general (How-To's and Why)
Elliott Sound Products http://www.sound.westhost.com/index2.html
About a week to a month's worth of reading. Lots of great info on the hows and whys of audio design, plus lots of great
projects to build, from beginner to expert level. He even sells parts and PC board kits.
Doug Self's Amplifier Institute http://www.dself.dsl.pipex.com/ampins/ampins.htm
Good reading, especially his article about distortion in amplifiers and how to weed most of it out of your design. Great
logical and systematic approach. He has also written some great books about audio design.
National Semiconductor's Application Note
Credit where credit is due, this project was inspired by Jon Chandler's Clock for Geeks.
After reading through one of Jon Chandlers recent projects, I was rather inspired to make my own! The Geek Clock is a great spin on a more then well known concept - displaying time. His method employs a Servo, PIC and a little intuition.
Rather then using the paper clock face like Jon did, I experimented with a few other methods to spice up the presentation. At work, we recently acquired a large Vinyl Printer and Gerber Cutting machine. Long story short, we can make all sorts of decal stickers (very handy indeed!!). It was a pain staking ordeal creating the clock face on the Omega software (for the vinyl printer/cutter) as it was written in the early 90's and very vector based graphics. In the end I got something that looked like a clock.
This Blog will not only tell you how to construct your home in Thailand, but also make sure it will be your own.
Thailand has very strange immigration laws, prescribing annual new visas even for retirement visas, and not enough of that retired foreigners have to report their residential address every 90 days to the immigration bureau. Failing that will be fined with Baht 2,000 (US$67).
Failing to renew a visa in time will be fined with Baht500, (US$17) per day of overstay to a maximum of Baht25,000 including an entry in the passport about the amount of fine with the possibility to be banned from Thailand in case of another overstay.
Further, "farangs" (Non-Asians) have absolutely no rights in Thailand, except for dumping their money there.
I have made acquaintances of Americans, Englishmen, Australians, Germans and Frenchmen who built an (expensive) house, purchased
PC Parallel Port Timer1 V1.1a
The program controls the PC parallel port pins 2 thru 8.
The high/low control for each pin is set manually or by using the inbuilt RTC timer.
The ParaTimer1.exe requires the Visual Basic 5 runtime files to be installed in the Windows/System folder.
These runtime files are free web downloads.
Unzip the file and install the DLL's in the Windows/System folder.
EDITED: 27th May 2011
Main folder rezipped and reposted, now ParaTimer1a.zip
Includes the VB5 Source File and *.exe.
Added: DllPort.dll to zip2
Sometimes we want to know the current draw of a device for various reasons. One reason would be to estimate the run time of the device when it is running on batteries. It is often very inconvenient to try to break the battery connections and insert a current meter or sense resistor, so here is an alternate method that does not require breaking the current flow. To accomplish this, we perform a series of very simple tests and from the results we can calculate the current draw. The tests do not involve inserting anything into the circuit in series with the batteries as most current tests require, so it makes it much easier to make the measurement overall.
If you have any questions feel free to PM me here to my screen name.
First i'll outline the procedure and then follow with an example where the device is a remote control transmitter that runs on four AA cells.
1. Measure battery no load voltage. This is with device turned off. Call it Vb.