7400 Competition Entry – Signal Strobe

This is my entry for the 7400 Competition. This a signaling strobe, an enhanced one with a siren. My device is built off of 7400 NAND Quad Gate, 2x 7476 J/K Flip Flop, 7432 OR Quad Gate and 4x 555 Timers. Now off course there’s a few passive components like capacitors, resistor, 5 volt regulator, LEDS and several switches. All built on one large breadboard, but I believe this could be fabricated on a 2×4 PCB, maybe smaller

To be able to complete the project for the 7400 competition I wasn’t able to find locally the I/R diodes or the high output LEDs that will mentioned later. I will good over it POU, point of use, and a bill of material will be included at the very bottom.


Using the master on/off switch either applies power to the circuit or removes it using the single-pole single-throw switch. After turning on, the strobe portion of the circuit has 3 conditions: A). Visible light strobe, B). Infrared spectrum strobe or C). both Visible and I/R together. This can be done one of two ways; by switching each light condition separately with the appropriate switch or, by using the switch marked both to activate both light conditions together. Once activated, the strobe lights, which are LED diodes, act in a “X” crossing pattern (wig-wag). The frequency in which the lights jump back and forth can be adjusted using the potentiometers, one for each diode type.

In a secondary circuit, powered by main 5 volt source, is a 3 watt siren circuit, similar to the American police siren. Just like the strobe portion, once the master power switch is activated, the siren is switched separately from the strobes to allow for selectable times of use. To activate the emergency siren simply depress the only push button switch on the device. There is selectivity to the siren too. By rotating the beige knob counter clockwise you can take the siren from a whooping sound to a high-pitched scream.

To return the device to the ready position turn the siren off, place the toggle switches for the strobe functions in the up position (towards to the top) and flip the master power to off.

Point Of Use(POU)

As the title describes, this device was intended to be used in Search and Rescue, Military, and any situations in which signaling from the ground to air is needed. This circuit utilizes 5 watt white LEDs as primary signaling illumination, with a 3 watt blue LED used as part of the alternating pattern. Secondary to the signaling illumination is a strobe pattern that includes 3 watt IR LEDs and one blue low power LED. The white LEDs provide upwards of 200 lumens, which has a usable viewing distance of approximately 250-300 yards. Using condition one of the strobe device it enables the white/blue strobe. Using three 5W LEDs and one 3W blue LED provides hundreds of feet of usable viewing bandwidth. White is used to stand out against most any terrain and one blue is used as a depth of field or contrast color. This depth of field and distance would be difficult to see if you were just using one color especially since blue is the hardest color on the human eye to view. This viewing difficulty allows for the greatest long distance impact in operating conditions.

As mentioned, there are two conditions to this device; the visible light strobe and the secondary Infrared strobe. Used in conjunction with night vision goggles, which amplify light (including a portion of the IR light spectrum), IR strobe can be a very useful tool. In night vision goggles, (NVGs) IR light does not diffuse as rapidly as white strobe would, especially in hazing or rainy conditions. Aerial operations, specifically in non-military S&R, typically work in the 400 – 750 ft of altitude range. This, as discussed above, is right in the sweet spot for the visible light white strobe and a more than safe range for IR. Just like the white strobe, the IR setup works in a crossing ‘X’ pattern. Two IR diodes flash and the next goes, which in this case includes one IR and one blue low power LED. Once again, this will give a good depth of field to the spotter.


Bill of Materials

Part used:

LED’s2 – 5W White

3 – 1W Blue

3 – 3W I/R Diodes

4 – 555 Timers 1 – 9 volt battery and caddy 5 – Single Pole Double Throw Switches 1 – LM7805CT 5v Regulator
1 – 7400 2-Input NAND Gates 2 – 1k Ω Pots 4 – 150 Ω resistors 1 – 2.2k Ω resistor 1 – 8 Ω speaker
3 – 1 Cap 1 – 7432 2-Input OR Gates 2 – 7476 Dual J-K Flip-Flops 2 – 100 μF Cap 1 – .1 μF Cap
1 – 1m Ω Pot 3 – 10k Ω resistors 2 – 1k Ω 1% resistors

Kenwood TM-V71A Dual Band: Installation in Dodge Nitro, Continued Part 3 – Mounting and Assembly



What I decided to do. The remote control head would be velcro-ed the a ledge on the dash. This ledge is slightly angled so that the display is angled upward for best viewing. I also have it rotated ever so slightly to even further improve the viewing angle.(Figure 5 & 6)

Next, where to mount the body of the radio? What I came up with is under the front passenger seat, towards the back. With the contours in the floor pan and the rear bench seat the way it is, this is really, I think my best option. One day if I feel adventurous I may mount it under that bench, but not today.

IMG_20121005_155925IMG_20120920_172933The radio mounting bracket started life as a small piece of 22 gauge steel I found on the side of the road. 22 gauge, how do I know? The sticker was still on it. This was crudely bent by hand to mostly mate up with the curves and contours of the floor. It mostly does. To attach my bracket in a permanent manner I left enough metal to drill a hole and use a seat bolt to hold it down.(Figure 7, 8 & 9) The pressure of the seat holds it firmly.

Now running the wire out from the radio over to the center console, which can be seen in figure 7 & 8. I then ran it through the center console all the way to the front. Up behind the dash and out where the knee panel meets the speed cluster surround.(figure 5 & 6, at the top)Using the factory Kenwood radio mount as a guide, I drilled 4 holes in the sheet metal. Then I bolted it together.

Basically this is all to my mobile installation. There’s a few extra pictures I’ll share here at the bottom.

I’ll write up my external speaker setup later.

IMG_20121005_192807 IMG_20121005_155947 IMG_20121005_155938


Space Shuttle Atlantis hands-on: a look inside (video)

Space Shuttle Atlantis hands-on: a look inside (video):

Space Shuttle Atlantis hands-on: a look inside (video)

Space Shuttles Discovery, Endeavour and Enterprise have all left Kennedy Space Center for new homes, but Atlantis? She’s staying. Come November 2nd, the orbiter will be wheeled out to a 65,000-square-foot exhibit, which is still being constructed at KSC’s visitor complex. Though the craft’s cargo bay doors will be open and its remote manipulator arm extended when its displayed, visitors won’t be able to climb aboard it — or any of the other shuttles, for that matter. However, we got the chance to visit Bay 2 of the Orbiter Processing Facility, step inside Atlantis and give it the hands-on treatment. Look out below for the gallery or hit the jump for the full video tour.

Continue reading Space Shuttle Atlantis hands-on: a look inside (video)
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Space Shuttle Atlantis hands-on: a look inside (video) originally appeared on Engadget on Sat, 06 Oct 2012 14:41:00 EDT. Please see our terms for use of feeds.

Kenwood TM-V71A Dual Band: Installation in Dodge Nitro, Continued Part 2 – Disassembly

To continue with with my previous post about my mobile installation of my Kenwood TM-V71A dualband. So we are done figuring out the logistics of actually setup up the remote head. Now on to my method of mounting.

As mentioned I’m driving a Dodge Nitro SUV. I initially thought that this mobile install was going to be a pain. Actually it’s not remotely difficult. Getting power into the cabin from the battery is super easy, opening up the dash is super easy, as is the center console and mounting both parts is easy.

Looking at the image to the left, figure 2, you see a picture of a Dodge Nitro dash. With the battery of the SUV being on the left side, drivers side, that is where I focused my efforts in wiring.

Looking at the image to the left, figure 2, you see the speedo cluster, the knee panel, radio area and center console.
1. I failed to snap a picture of the removal of the speed cluster dash area. But it is as follows. Lower the steering wheel all the way down. Firmly grasp the top most forward plastic and pull back towards yourself.

2. Two remove the knee panel that is below the steering wheel. The the top plastic edge of the knee panel exposed, firmly grasp and pull down with even force. Doesn’t take much at all. Only two clip hold up the hinged panel. Once it has hinged down as far as it will, slide the panel 3 inches to the left and it comes off.
3. If you look at the shifter there in the front middle off the console.(Figure 3) You see the frame that looks like brushed metal. It is plastic so go easy. If you are in this truck looking down at it, you notice a gap between the shift base and this faux metal area. Insert  tips of your fingers and pull up gently. It helps to engage the ebreak.

4. Next if your sitting in the back seat looking a the rear of the center console near the floor you’ll see that the back cover is one piece. Very easy, just grasp it and pull slightly. I’ve included a picture with it removed as I don’t have one from before. (Figure 4)

5. Lastly after popping the hood move to the drivers side, near the brake master cylinder. Look on the firewall under the brake master cylinder and to the right near the fender. In this area there are two pass troughs on the firewall. On my vehicle one is fully in use from the factory but the over merely looks like a rubber plug. Pull the out the plug. No tools needed, it just pulls out. Don’t those it.

Disassembly Complete.
To be continued…

Continued in Post 3: Mounting and Assembly


Kenwood TM-V71A Dual Band: Installation in a Dodge Nitro

This write up is on an installation of a Kenwood TM-V71A Dual Band VHF & UHF mobile amateur radio into a Dodge Nitro SUV. The Kenwood TM-V71A radio is a modern radio with remote control head capability. Technically a remote head kit available from Kenwood is required to take advantage of this feature, but in reality this isn’t true. The remote kit certainly will make your installation easier. The kit would include a adapter and bracket to attach the head to and the specialized cables to hook the head to the body. The basic remote kit only includes an extended cable for the head to radio, no extension for mic to radio. There is an extended remote kit available that I believe has the basics, plus a extended mic and power cable adapters.

With that said, here is how I did it. If you take a look at the small cable that hooks the remote head to the body when they are hooked together you will see that one end is a RJ-45connector(standard ethernet connection) and the other end is a slim RJ-12 connector. Similar to a telephone line(same wiring), but about 1/4 thinner. Then at the termination of the mic cable you’ll see that the connection is also a RJ-45 connector. These two RJ-45 connections are standard size. So to extend this to connections I acquired two RJ-45 male to male couplers, as scene in figure 1.

I should mention I looked for a couple days for this special RJ-12 cable with no luck. I could have fabricated something up, but my method is easier.

To complete all these extended connections here’s what you will need:

  1. 2x RJ-45 couplers
  2. 2x Ethernet Cables(for efficiency’s sake, short as possible)
  3. 2x Ferrite Choke(Optional)

Step 1. Plug a coupler onto each ethernet cable
Step 2. Plug an ethernet cable into the head and into the microphone plug
Step 3. Plug the appropriate end of the include head wire into your extension
Step 4. Make your mic connections

Now this is an optional step but in the kit you can see that cable has a ferrite choke to keep RF emissions traveling down your remote cable. I ordered two from Mouser. I’m going to do it.

***Found these specifically fitted for CAT5 cable***

Continued in Post 2:Disassembly