|More than 8,000 searchable pages indexed.|
Your RF Cafe
Airplanes and Rockets:
March 1959 Popular Electronics[Table of Contents]People old and young enjoy waxing nostalgic about and learning some of the history of early electronics. Popular Electronics was published from October 1954 through April 1985. All copyrights are hereby acknowledged. See all articles from Popular Electronics.
This might be the first appearance of Carl's father, at least in a drawing. In this episode, Carl and Jerry design and build a "polecat detector." In the process, a little drama is thrown in when a stander-by mistaken believes he is being insulted. Even if you don't learn how a photocell-based threshold crossing circuit works, you might just learn the meaning of 'lugubriously.'
By John T Frye
Carl and Jerry were perched on the workbench of their basement laboratory listening to Carl's father as the big, pleasant-featured Mr. Anderson said:
So when your mother saw that skunk go under our house, Carl, she was really 'shook' as you boys put it. She's threatened my life if we do anything to upset the little beast there because she still remembers how, when she was a girl down on the farm, her dad set the dogs on a skunk under the house. The whole family had to move out and live in the corncrib for a month."
"How do we know the polecat's still under there?" Carl asked.
"We don't. Possibly it's gone away. But we don't want to be 'half-safe' and close up that opening until we're sure. That's where I thought you electronic hot-shots could help. Can't you rig up some sort of electronic device that will let us know if the skunk comes out from under the house? I mean some sort of gadget that will sound an alarm if something comes out through that hole but will stay silent if something goes in."
Jerry's round face wrinkled in a frown of concentration. "Ye-s-s-s," he finally breathed, "that ought to do it!" He grabbed up a piece of chalk and began to sketch his plan on a blackboard.
"Here's a transistor with a high-sensitivity relay that I'll label RL1 in the collector circuit. The transistor's biased so the relay is held closed. Notice we have a 1000-μfd. capacitor across the relay winding. Here's a selenium photocell. When a beam of light shining directly across the opening under the house falls on this cell, it generates a current that bucks out the transistor bias current. That causes the collector current to fall nearly to zero, and the relay opens. If anything interrupts the light beam, the collector current rises and the relay closes . The voltage across the relay coil charges the capacitor, and the discharge current from this capacitor keeps the relay closed for 30 seconds or so after the light beam has been restored. Okay so far?"
"Check!" Carl said promptly.
"Fine! Here's another relay-transistor-selenium cell/light source combination that's set up a yard or so from the wall of the house. The only difference is that it has no capacitor across the winding of RL2. This relay also stays open until its controlling light beam is broken. Then it closes; but, unlike RL1, it opens again immediately when the light falls on the cell again.
"Now the contacts of RL1 and RL2 are connected in series so both have to be closed simultaneously before current through them will actuate this heavy-duty relay, RL3. Relay RL3 controls this solenoid. When the solenoid is actuated, it pulls out a pin that lets a gate fall down across the opening under the house. At the same time it turns on a switch that starts our tape recorder. An endless loop of tape on the recorder keeps repeating a warning message over and over."
"I think I get it," Carl said slowly. "If the skunk is outside now and goes under the house, nothing happens. He will break the beam that controls RL2 first, but this relay will open again immediately after he has passed; consequently, when he breaks the beam of RL1 and it closes, RL3 is not actuated. On the other hand, if he tries to come out, RL1 will close immediately when he pokes his nose out of the hole. It will stay closed as he comes on out and walks a step or so and breaks the beam of light controlling RL2. When this happens and RL2 closes, RL1 is still held closed by the discharging capacitor. That means RL3 closes and works the solenoid that drops the gate, sealing off the opening under the house, and also starts the tape recorder to let us hear the 'all clear.' "
"Even I can understand that," Carl's father said with a broad grin; "and it sounds like a fine idea. How about letting me dictate the glad tidings on that loop of tape?"
"Sure thing," Jerry said as he took the cover off the tape recorder. "We'll leave the recorder in here and hook up another speaker outside the house. Then we'll hear the message whether we are inside or out."
By chance this message filled the loop of tape exactly so that when the recorder was running the warning was repeated Over and over without interruption.
"I'll run over and try to coax your mother down off the chandelier and explain that we have the situation well in hand," Mr. Anderson said, "while you boys start work on your direction-of-skunk-movement indicator."
It didn't take long for Carl and Jerry to assemble the comparatively simple apparatus. From long experience the two boys worked together smoothly and efficiently. They mounted the photocells inside mailing tubes to shield them from bright daylight. The light sources were 117-volt bulbs with simple reflectors and hoods to send the light directly into the ends of the mailing tubes. Since the lamp-to-cell distances were short, powerful lights were not needed. They arranged little fences so that an animal going in or out of the small opening in the house foundation would have to break both light beams in sequence. A light lattice-work gate was set so that it dropped in front of the hole when the solenoid pulled a prop out of the way.
By the time everything was finished, the sun had gone down. The boys sat on the front steps of Carl's house and enjoyed the unusually warm March evening as they talked over their installation to make sure nothing could possibly go wrong. As they talked, Carl's father came out the front door wearing his hat and coat.
"I'd certainly like to stay here and see what happens with the polecat detector," he said ruefully; "but I just got a telephone call that disturbs me. As you know, I'm running for city councilman in the primary. Pat Gallagher down the street is running against me. Just now I got word that some low-lifer has told Pat a string of lies about what I am supposed to have said against him; and he, quite understandably, has his dander up. I'm going over there right now and straighten things out before they get worse - which they can very quickly. Pat's got a temper that matches his red hair, and I don't want him mad at me. I'll be back as soon as I can - hey!" he broke off; "There goes Pat across the street now."
At this precise instant there was a muffled bump at the side of the house, and a few seconds later a voice bellowed forth:
"There goes the skunk! There goes the skunk!"
The two boys and Mr. Anderson raced around the house. The gate had dropped, closing off the hole, but the skunk was not in sight. Jerry walked over and threw the switch that stopped the tape recorder. It was not until then that the three of them noticed a little red-headed man come bounding around the house, peeling off his coat as he ran toward them.
"Stop, you big hulking coward!" he shouted at Mr. Anderson. "I'll teach you to call me names and then run. Put up your dukes, man; don't shame yourself in front of your own flesh and blood."
"Now hold on, Pat," Mr. Anderson said as he moved away from the little man who was dancing back and forth with his clenched fists held stiffly in front of him in the style of the immortal John L. Sullivan. "That wasn't me you heard. Jerry, turn that thing back on and show him."
"Don't add lying to your other black-hearted crimes! I know that Bull of Bashan voice of yours when I hear it. Are you going to fight or am I going to have to-"
At this moment bedlam broke loose. The tape recorder began shouting its message. A small black animal with a white stripe down its back and along its tail tore around the back corner of the house and raced toward them with Bosco, Carl's dog, in hot pursuit. In the distance they heard the wail of an approaching siren.
The skunk dashed for the hole in the foundation, only to find it closed off. He was trapped. He had to use his secret weapon. Before the horrified gaze of the four people, that plumed, white-striped tail came up and a horrible, choking stench enveloped the whole area.
Poor Bosco got the worst of it because he was closest, but there was plenty to go around. The dog howled in agony as he rolled on the grass and pawed at his stinging eyes. The men and boys fled blindly toward the front of the house. The skunk then sedately and daintily picked his way past the writhing dog and disappeared around the back of the house.
Two patrolmen piled out of a squad car at the curb and came racing toward the group on the front lawn, but suddenly they got a whiff of the rich odor and came to a stiff-legged halt. "What's going on here?" they asked. "We got a report two men were fighting."
"Someone must be mistaken," Mr. Anderson said blandly as he tried vainly to breathe by exhaling only. "I've seen no fighting here; have you, Mr. Gallagher?"
"Certainly not," Pat answered promptly.
"Things have come to a pretty pass when a man can't get rid of a skunk without being badgered by the police."
"Who's that blatting away about 'There goes the skunk,''' an officer insisted.
"That's just a tape recording; and it's too long a story to tell now," Mr. Anderson said. "We've got to see what can be done about decontaminating ourselves. Pat, we've got a shower in the basement, and I've got some old clothes down there you can wear home. I'm afraid we are all going to have to bury what we're wearing."
"That's mighty friendly of you, Steve; and I'll take you up on it. Sheila would never let me in the house in this condition."
"Okay, gentlemen," one of the officers said as he got back into the squad car; "but if you don't mind, I'd like to make just one remark - quite respectfully, you understand. I don't know what kind of a campaign you two intend to put on, but it certainly is off to a smelly start!"
As the squad car drove off, Mr. Anderson and Pat Gallagher looked at each other for a long second; then an irrepressible smile crinkled Pat's Irish face. Mr. Anderson pounded the little man on the back, and all four whooped with laughter as they trooped toward the basement entrance of the Anderson house. Jerry flipped off the switch on the recorder control, and the voice coasted to a stop.
"There goes the-e sku-u-u-u-nk!" it said lugubriously.
Carl & Jerry: Their Complete Adventures is now available. "From 1954 through 1964, Popular Electronics published 119 adventures of Carl and Jerry, two teen boys with a passion for electronics and a knack for getting into and out of trouble with haywire lashups built in Jerry's basement. Better still, the boys explained how it all worked, and in doing so, launched countless young people into careers in science and technology. Now, for the first time ever, the full run of Carl and Jerry yarns by John T. Frye are available again, in five authorized anthologies that include the full text and all illustrations."
Carl & Jerry Episodes on RF Cafe
- Abetting or Not? - October 1956
- Electronic Beach Buggy - September 1956
- Extra Sensory Perception - December 1956
- Trapped in a Chimney - January 1956
- Command Performance - November 1958
- Extracurricular Education, July 1963
- Treachery of Judas, July 1961
- The Sucker, May 1963
- Stereotaped New Year, January 1963
- The Snow Machine, December 1960
- Extracurricular Education, July 1963
- Slow Motion for Quick Action, April 1963
- Sonar Sleuthing, August 1963
- TV Antennas, August 1955
- Succoring a Soroban, March 1963
- "All's Fair --", September 1963
- Operation Worm Warming, May 1961
- The Crazy Clock Caper, October 1960
- Two Detectors, February 1955
- Tussle with a Tachometer, July 1960
- Therry and the Pirates, April 1961
- The Sparkling Light, May 1962
- Pure Research Rewarded, June 1962
- A Hot Idea, March 1960
- The Hot Dog Case, December 1954
- A New Company is Launched, October 1956
- Under the Mistletoe, December 1958
- Electronic Eraser, August 1962
- Blubber Banisher, July 1959
- "BBI", May 1959
- Ultrasonic Sound Waves, July 1955
- The River Sniffer, July 1962
- Ham Radio, April 1955
- El Torero Electronico, April 1960
- Wired Wireless, January 1962
- Electronic Shadow, September 1957
- Elementary Induction, June 1963
- He Went That-a-Way, March1959
- Electronic Detective, February 1958
- Aiding an Instinct, December 1962
Posted June 23, 2014