Ha, I built the VTVM as a high school project, but I really wanted to build the FET meter because it was more portable. I think the FET meter was not available at the time of purchase (out of stock) so I built the VTVM but always felt disappointing. I never gave it too much thought, and certainly threw my VTVM away years ago. Now I find out after all these years that I had built the preferable model. I doubt I would have used it around the house instead of the very small hand held meters which have been available for years.
You would not have been happy with the FET meter. I sure wasn't, that was te only really disappointing kit fro Heathkit. Plus their chinzy plastic cases broke at the fold within a couple years and then the top lid sailed off. They though that a thin strip of extruded plastic could double as a hinge. It couldn't.
VTVMs have another major advantage. They can perform in the presence of humongous EM fields without erring and, most of all, without something going *PHUT* in there. So to this day, if the going gets tough the old VTMT comes out of the garage. Mine is from Eico.
I remember when you built that. But you are an engineer. Imagine what it means to people if a kit manufacturer offer the required pieces so even non-EEs can do this.
Home automation is a totally underserved market. You cannot buy any reliable stuff at reasonable prices, you can only build it yourself.
I built, and used both. The VTVM had less drift, but the IM-25 FET meter was more versatile, including battery operation. Both were line powered, and neither needed repaired in all the years I owned them. I also assembled some other Heathkit VTVMs for others who got the kit and didn't want to put it together.
You can see that the IM-25 did quite a few things a typical VTVM didn't, while having the same isolation at the probe for DC measurements.
Plain PDF, text, or html (ie non-proprietary, open source) are the only acceptable eBook formats for me. Because open source mitigates future changes in business rules that favor the interests of other parties over my own interests.
Publishers are doing a lot of soul searching about how to remain viable in this eBook era. My suggestion is to ignore the worthless criminal pirates and simply trust your own valuable readers to do the right thing.
Long story short, if _Circuit Cellar_ can deliver their magazine in plain PDF format, everybody else can too. If they so choose.
Getting back to hobby kits, it seems to me that kits teach much more than simple board stuffing. Kits also familiarize students with components. In this twisted (pair) world kit builders probably stand a better chance of feeling uneasy about simply connecting a twisted pair to a 1970s era audio (guitar) cable.
It's a sight to behold a brand new building with the intercom audio jack of state-of-the art VOIP servers plugged directly into twisted pair. Accompanied by the inevitable ground loop noise from the overhead speakers. What this world desperately needs is 1970s era guitar players who recognize ground loop noise when they hear it.
About those brand new overhead speakers installed in that brand new building. Each speaker contains an old school, single sided, through hole, PCB board that uses a circuit built around a big old LM386 DIP chip. Just the type of board that kit builders used to stuff all of those decades ago.
I agree, but please ask yourself WHY it's such an under served market.
I service a customer that has early version of one of these: It can do almost anything except pay the bills. This one is mostly used for home security and running the entertainment system. My guess(tm) is about $25,000 installed.
I don't actually service the Elan hardware. That's locked up tight by the vendor by not releasing any technical information, not selling component parts, and working only through authorized dealers. I have no problem with that, except that it does get expensive. I work on the plug in peripherals while the authorized dealer does the programming (usually over the internet).
In the very distant past, I also thought the world needed a home automation system. However, I wasn't so ambitious. I just wanted to automate the kitchen appliances by making them talk to each other. Bar code tags on everything, optical reader in the refrigerator door, touch screen CRT in every corner, and a computer to orchestrate it all. I also spent considerable time on a science fiction business plan.
When I presented the idea to the investment group, complete with a somewhat working demonstration, they were skeptical but impressed. As always, the members of the group did an impromptu marketing research survey, which meant they asked their wives. The most common result was an instant refusal to even listen to my proposal. All the wives indicated that the kitchen was their territory and no electronic gadgetry was going to cook, manage, control, organize, or otherwise do anything in their kitchen. By the same logic, managing the home is also the women's territory, where I would expect similar results to any attempts at automation.
An important clue is in the introduction of microwave cooking and it's effect on packaged foods. Microwave frozen dinners, which are prepared by putting the contents into the microwave and just pushing a button, have problems selling in some markets. Meanwhile, the same packaged dinner, with some key ingredient missing (typically butter), or which require stirring in the middle of cooking, sell much better. That's because the woman of the house does not consider it cooking unless she does something with the contents.
This effect also extends to the design of the oven itself. I once did some work for a microwave oven manufactory on RF leakage issues. At the time, I saw what would today be considered some fairly advanced designs. One design was self calibrating so as the magnetron slowly decreased in power over the life of the oven, the cooking time would automatically be extended. In addition, a system where each package was bar coded, and read inside the microwave oven, was devised. The oven could then query a database, or use the data on the bar code, to set the power level and cooking time. The problem is that none of these ever made it out of the lab because of buyer resistance. Nobody wanted a robot oven.
When trying to automate the entire house, you'll run into things like the aforementioned territorial problem. Some areas are easy, such as security, outside lighting, environmental control, computah networking, and entertainment systems, which are generally considered to be the mans territory. However, do anything within the confines of the kitchen, laundry room, guest areas, or bedrooms, and you'll need to find a way around this problem. As a clue, the previously mentioned Elan system is operational throughout the house, except in the kitchen. There's even an LCD panel in the bathrooms and garage, but not the kitchen.
Speaking only for myself, I see enough electronics and computahs in my office and at customers. When I go home, the very last thing I want do deal with is more electronics. There was a time in my life, when I had no computer, no automation, no microwave oven, and no TV in the house. I was looking for a life without the maintenance aspects and complexities of computers. I may go back to that if I ever retire (or burnout). Meanwhile, home automation and running my life by computer is NOT on my wish list.
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Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
That's the deluxe table-top edition which was ok. I had the "portable" one in the diarrhea-colored slanted suitcase. That was IMHO junk. But the only junk I ever had from Heathkit, the rest of the stuff was (and some still is) remarkably good, and most of all sturdy.
A Raspberry pi or one of the similar things can run Linux hence access Dropbox. A couple of simple accessory boards could provide clean i/o. There are surely good webcam apps for Linux. All that needs now is a good software library and a very good manual.
3rd party guys could provide higher-level apps for people who don't want to program.
I used a mini-ITX running XP, because that's what I know how to do, but that cost many times what one of those tiny Linux boards would cost.
Why? Because the stuff is overpriced and companies attempt vendor-lock. Some will not even sell to the public but you must pay an installer. That's not going top fly for the masses. This is the reason, and Heathkit (or any other company) could change that.
^^^^^^^^^
There you have the reason.
And there you have the reason for the reason :-)
I do have a problem with that. I will not buy such a system, and won't recommend it.
That's almost as if the Wright brothers had tried to build a space shuttle right off the bat :-)
Because it was over-engineered. I had that same talk with my wife and when looking at the X-10 options she was very enthusiastic. After I was done she could hit a button next to the bed, turn around one more time, and only get up after fresh coffee small wafted in. The espresso maker could be started from the yard, without having to leave the table of friends and walking upstairs. She likes ping-pong games, but that needs light in the evenings. The switch is upstairs and suddenly that was no longer a problem. The whole house could be lit with Christmas lights with one press of a button on a remote. And so on. She loved it.
However, we quickly found out that the quality of most X-10 modules was miserable and that the transmission protocol is very poor.
But ... that misses an important market: The students and the bachelors. Those use microwaves for just about anything. For many of them nutrition and eating is a necessary evil unless it's with the guys at the pub. On of my grandpa's once summed it up: "Why don't we have a lid in out bellies which we can open, throw some food in, close it, and be done with it?".
Same in companies. Other than the coffee makre the most frequently used piece of equipment in the lunch room is ... the microwave.
My wife would want one in the kitchen. For example, she'd like to be able to control the sprinkler zones from there. Mounting the fairly ugly utilitarian Toro box in the kitchen would, of course, not be an option. Did Toro offer a remote with enough functions? Nope. She'd also like to be able to program TV stuff from there. But no reasonably priced systems exist. This is where a new company or a revived one like Heathkit can come in.
Same here. Turning a hobby into a career often snuffs out the hobby.
It sure is on my list (ours). Because every time the remaining X-10 stuff goes on the fritz I have to dive into electronics on a weekend and, for the reasons you mentioned above, I really don't like that.
Ahem. You might enjoy the Heathkit GR-98 aircraft monitor receiver with the backwards AGC (automatic gain control). The first units that I saw worked fine on weak AM signals, but strong signals had low audio. We had some difficulty convincing Benton Harbor that there was a problem. It was eventually fixed with a "field modification".
There are other Heathkits with design problems, but that was the worst that I can recall.
I have an IM-25 VOM and use it ocassional. Most commonly, I use a Hi-V probe for measuring gieger counter voltages where anything less than about a 50M load will ruin the measurement accuracy. The IM-25
11M input impedance is nice, but not quite high enough.
At one time, I had an IM-17 FET VOM, which may well be the worst meter that Heath ever produced. All it ever did was drift, even with a real mercury battery:
One thing nice about Heathkits was that with a manual full of theory of operation, waveforms, voltages, and troubleshooting instructions, they were very easy to repair.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
We had an alarm company do the security and fire system. The insurance folks want a fire system, one that's certified by the makers and tested by the SFFD, and checked regularly.
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John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com
Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
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