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My 8yr old son, Alex, practices his spelling words in Morse code every night. He gets 50 homework points for coding his spelling words in any way he likes so why not learn Morse code at the same time, right?

Until now he has been using my Fluke 87v multi meter with an old J-38 Morse key. When the Fluke is set to continuity it works great as the buzzer. I have many other meters with a continuity setting but only the Fluke 87v has a fast enough continuity tester to match my son’s practice speed.

I really wanted my Fluke back on my tech bench so we found a circuit he could build himself to use as the buzzer in place of my Fluke.

Alex is the host for this video and he seemed to have a lot of fun making the circuit and the video. GOOD JOB Alex!

This is the circuit Alex builds in his video to replace the beeping my meter was doing in his old setup.

He started off with a great introduction on why he was learning Morse code.

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The (SARC) Superstition Amateur Radio Club of Mesa, AZ needed to replace their UHF/VHF repeater antenna and repair the hard feed line which had a large dent in it from years back. This video shows the club taking down the tower, replacing the antenna and fixing the hard line.

One member volunteered to climb the tower to connect the strap and tow cable. This tower’s base is on a hinge so to bring it down you only need to remove some large bolts.

A local towing company volunteered their crane truck and a driver for a couple of hours. Thanks Apache Sands towing it was greatly appreciated. Some more volunteer members pulled on a counter rope and the tower is on its way down at the command of the tow truck operator.

The tower is lying down nicely on some old tires.

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I updated my tech bench with 4 shelves and 32 outlets! In the past I stacked my tech gear like it was in a Dr. Seuss book and I shared 1 outlet for all my gear. I finally got sick of the mess and inconvenience.

This video is showing my wiring install and shelving choices. I do cover reasons I picked curtain solutions and at the end is a tour of all my tech gear.

Below, behind me in the photo, is what my tech bench looked like in the past. What a mess! Very difficult to use or power anything.

The starting point of the video was when the shelf brackets were installed and so were 2 of the 3 junction boxes.

I’m routing the power from the old spot to this new junction box that will be above the first shelf and easy to reach. The left box is for the overhead light switch as well as the switch for the old corded power rail at my tool bench to the left of my tech bench. I cut the plug off the old corded power rail, tined the braded wire and secured the cord at the lower part of the junction box. The larger box on the right is for my GFI outlet and a switch to turn on/off all the power at the tech bench

Make sure to mark where the outlets will be on the back rail with “X”s and lines. Try not to put any screws in the marked areas unless you use very shallow heads. If you use large pan head screws in the “X” areas the outlet rail will not snap onto the back rail.

The back rails, boxes and conduit are ready. You don’t glue this type of conduit. Just push it together and use clamps to hold longer runs to the wall. You should plan for pulling wire. So leave a few open elbows or 90 degree joints with an access plate. My runs were short so I could just put everything up and pull wires later.

Below is the original 20A dedicated power feed to my bench and a 2nd wire that goes up to my overhead garage lighting just over my tech bench.

This is a close up of the junction boxes with conduit installed.

Great! All my wires are pulled. It was very easy because the runs were short.

The feed power and wires that will be used to switch the overhead lighting are now installed. I used quick wire clips “In-Sure Connectors” instead of wire nuts as you can see. It does make wiring a ton easer because you don’t have to fuss holding 3 to 6 wires, twisting them and then crank on a wire nut. With these quick wire clips you just work with one wire at a time. Much less fuss, trust me. The connectors are made by IDEAL and I get them at Home Depot. Search for “In-Sure Connectors” What is really nice is one size fixes all. The connectors work for #20 up to #12 AWG wires even at the same time. So if you have #12 supply going into a fluorescent fixture with #18 hookup wire the connectors still work just fine.

The left end of each power rail had a $5 junction adapter which was in addition to the $34 power rails. The overall cost is not bad when you have 300 feet of 12 gage stranded wire leftover from other wire install jobs. If I had to buy the wire I might have picked 12 gage 2 wire armored cable and all metal construction for the ground return. That would be less wiring and being I can buy that by the foot at Home Depot I could have had a series solution with less than 3 feet.

That brings up a planning error I made. I should have run all the power rails in series because that would have made the wiring in the one main junction box a lot easier. And the install would have looked a lot cleaner. But I chose not to because I waned to save the $10 for the two extra power rail junction adapters that would have been needed for a series run. All the outlets on both benches are on the load side of my GFI so I’m protected from a grounding fault. That is standard in a garage and don’t be cheap with the GFI at your bench!

All buttoned up and ready for a test! In the video you will see I do find a fault with one of the quick wire clips. One popped off when I pushed them into the main junction box. After reviewing my footage I found I had not put the wire security into the clip so that was my fault. Those clips work great if you are careful to insert your wires all the way to the back. The ends of the quick wire clips are clear so you can easily check your work.

Now everything is testing great including my under bench lighting which is plugged in at the end of the lower power rail. This way the under shelf lights come on only when I turn on the tech bench outlets.

Looking good, just needs gear!

My workstation ESD mat: I put the mat’s grounding wire in a hole and under the bench to keep it out of the way.

The grounding wire comes back up another hole near the power junction box for my bench. The black wire in the below photo. Being this metal junction box is earthed I attached my ESD mat grounding wire to a cover screw at one corner. Under the bench I just stabled the wire up and out of the way.

The bench is all loaded up with gear. At the end of my video I give a tour of my gear if you’re interested. Click the below image for higher res.

Thanks for joining.

Todd

My wife bought a candelabra LED style bulb to test in one of our chandeliers. We had hoped to drop from using 40 watt incandescent to 2 watt LED bulbs.

That would be a saving of 228 watts in one chandelier and throughout our house the swap would have a total savings of 570 watts. Not a bad idea but the one we bought to test died in less than 2 weeks. It might have only been one week even.

I thought it would be fun to dissect it and see how it failed and maybe how it worked. Here is the video:

What better way to dissect electronics than with a hammer. “I got me’amer” – Photonic Induction.

It hammered apart quite nicely without any damage to the innards.

The pyramid was just a pack for 28 LED’s tightly packed using insulated standoff tubes. I was not sure at first if all the LED’s were in series or if there was some paralleling going on so the voltage could be lower to drive the LED’s.

It was not a complicated circuit. Some filter caps, two resistors, a diode and a SMD bridge rectifier.

Holly crawdads! It still works? I’m thinking the shrink wrap around the PCB was a bit small and it had managed to short the case to the wire feeding the LED’s. I also noticed one leg of the MB6S bridge rectifier IC was not soldered down and it had almost zero copper under the leg so that could have been causing an intermittent as well.

The Fluke says the PCB is putting out ~81V DC.

The AC ripper riding at the 81V DC offset was quite pronounced at 26V PP. But the LED’s didn’t seem to mind and the human eye couldn’t pickup any 120 Hz flashing if it was causing a problem.

The LED’s themselves draw 9.45mA. Not bad for 40 watts of equivalent incandescent lighting output.

I set my power supply to series mode to output my max at 63v DC. That wasn’t enough DC directly across the 28 LED’s to turn them all on so without any further circuit tracing I can tell the LED’s are in series being each white LED needs over 2v to be forward biased.

I must have been real close to turning the pack on with 63v DC because when I jumper across a couple less LED’s the rest of the LED’s came on. A little more probing with the 63v DC source went too far and “I popped’it” – Photonic Induction again I sure wish Photonic Induction wouldn’t have pulled off of YouTube. I loved that YouTube channel. The blackened LED’s are the ones I popped with too much voltage. It was fun while it lasted.

Thank you for joining.

Todd

This is footage of the (SARC) Superstition Amateur Radio Club’s tower in Mesa, AZ.

Our ham radio club has used this tower and antenna for many years but it is now in need of repairs. The club wanted some footage to help plan the repairs. The buzzing in the shack is an over voltage alarm which will be fixed with the repairs along with a new antenna.

More information on the SARC website at: http://wb7tjd.org/wiki/Superstition_Amateur_Radio_Club,_Inc._147.12

This is a full review of the USB microscope that is sold by Adafruit. It does 20x to 200x and also will let you take measurements if you enter the magnification you are using. I will let the video explain everything but I added some extra photos after the video.

I paid $79,95 for this from Adafruit.com when they first came out months ago.  Sorry for the delay but this did give me some time to really get to know all the features. I’m very happy with this USB microscope and have used it quite a lot. In the past I would have to put an eye loupe in front of my camera to take circuit close ups but this microscope does a lot better job. Inspecting very fine details and solder jobs is also tons easier with this microscope.

The box:

The USB microscope:

Setup and working:

I wanted to be able to have my circuits in my Panavise when using the USB microscope. I had a flex mic-stand from Radio Shack and some salvaged magnets from some old speakers. I hot glued one large magnet to the top of the mic-stand and another to the bottom of the USB microscope stand. With this setup I can easily switch between the desktop and my mic-stand when I need more flexibility.

An example of the close up of a (06 x 03) smd resistor using the photo button in the software. REAL NICE!!!

Below is my last example of using the measurement feature included with the software. It worked quite nice but I do wish it had more resolution like 0.001 would have been a better minimum than 0.01 for measuring close ups. This last photo was captured from my video of the laptop screen. I really should have uploaded a real screen shoot from the microscope because that would have look much better, like the one above.

Thanks for joining!

This is Part 6.  It is the final installment because I did get the power supply working. You may want to first follow (part1), (part2), (part3), (part4) & (part5).

Somehow I or the crap designed circuit damaged one or more of the chips during part 1.

I started by testing my extra PWM chip (UC3843N) on a bread board. It was a new chip which was never used and it was testing fine until I turned the wrong knob and let out all the magic blue smoke. I took out the PWM chip that was in the control board since part 1 and it tested as bad. In fact Vcc was being shorted to ground. That explained a lot.

I ordered another PWM chips from Digi-Key and after installing it the controller and motor started working. I was having some speed regulation issues which I attributed to not having the heat sinks connected. At that time, which was the end of my video, I assumed the controller was functioning the best it could considering its poor design.

After delivering the motor and controller to HeatSync Labs one of the clever hackers there looked into the speed regulation issue which was not clearing as I thought it would once the heat sinks were mounted. He found another chip on the board that was bad, one of the op-amp chips. It was a chip I too had replaced over a year ago so something was killing the chips on the control board quite easily. This control board was such a pile of crap from day one.

It is working marvelously now so if you’re ever in Mesa Arizona swing by HeatSync Labs and try out their great little mini lathe. Maybe make yourself an aluminum chess piece or two.

Thanks for joining!

Today I’m going to show a video on how to troubleshoot and repair a timer control. I will be sharing my evaluation of the problem and my final solution. Along the way I demonstrate three different methods on how to remove electronic components and I give some hints to make it easier. I show how to fix a fused relay and in just this blog posting, not the video, I also document how to test a bipolar junction transistor (BJT).

The three methods I cover are:
1) Manual desoldering pump at (adafruit.com)
2) 30 Watt Electric desoldering Tool at (amazon.com) or (elexp.com)
3) Solder wick at (adafruit.com)

If you don’t care to watch the video I will summarize below.

I have an exterior timer control that turns my Christmas lights on at dusk and off after 6 hours. I noticed they never turned off one day and thought I had left the timer control set to the ON position. But no, it was set to off 6 hours after dusk. I then set the selection switch to OFF but still it was on. I unplugged and plugged it back in but got the same problem. It was time to go to the electronics bench.

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Today I’m going to reviewing two types of Pomona test lead holders.

A representative from Farnell contacted me and asked if I wanted to review some products. I said, “Sure, free supplies for my lab!” Actually, I found out that anybody can sign up for their product “Road Test” program at Element14.com but not everyone is selected. Farnell is a European company and known as Element14 in Asia and Newark in America (online catalog). But they also have a nice online community site at Element14.com/Community where you can get to their “Store” for your region.

For the “Road Test” I chose to review some different test lead management hangers made by Pomona. I have quite the mess of jumpers, patch cables, DMM probes and oscilloscope probes hanging on my peg board behind my lab bench. That is not a good way to store these and they are very difficult to access on peg board.

I selected two sizes with two different mounting options for this review. The Pomona model 1508 with 14 slots at 0.21in (5.33mm) opening is great for jumpers, patch cable and test leads. The 1508 model needs to mount using screws.

<photo 1508>

I also got the Pomona model 4408M with 8 slots at 0.32in (8.13mm) opening with magnet mounting. The 4408M is nice for oscilloscope probes and larger items.

<photo 4408M>

I was quite disappointed to find that you lose two slots for the magnet mount because they just bend the outside prongs down and add stick on magnets. This magnetic option drops a model 4408 with 10 slots to a 4408M with only 8 slots. If I had known that I would have got the model 4408 and just added my own magnetic plate. The photo for 4408M at Neward.com is curretly wrong and shows the model 2708 without bent prongs.
The magnetic option was not strong enough for the thin metal in my garage door anyway so I bent the two extra prongs up and used the screw mounts.

You can fabricate your own test lead hangers but at these prices it just makes sense to buy.
1508 is $17.53 USD (at the time of writing this it is on sale for $12.46)
4408 is $14.65 USD  (at the time of writing this it is on sale for $10.43)
4408M with magnet mount is $32.13 USD  (at the time of writing this it is on sale for $23.46)

Here are the after shots of my lab. WOW these hangers sure helped clean things up and I have already found it much easier to find and select items.

I even found some lost jumpers and micro hooks. I thought they were gone forever but were just under the pile of cables hanging on my peg board. I will not be losing track of such items anymore!

I guess I will have to get one more 1508 because I have so many jumper cables. I may even get their biggest hanger model 2708 with 9 slots at 0.45in (11.43mm) opening for my PC power cords and wall warts.

Thanks for visiting.

On 11/28/2011 I was honored with being the “Featured Engineer” of the day at www.EEWeb.com. You can read the full Featured Engineer interview if you want to learn a few tidbits about my history and career in engineering.