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Mike Saunby got his hands on one of the most interesting old clocks I have ever seen. It does time and date which isn’t any great feat by todays standards but have a look at the complex electro-mechanical goodness that makes it tick. The big question here is who made the thing, there are no markings on the clock to give us any clues. Anyone know? There are some high resolution pictures here. "The clock mechanism The clock relies almost entirely on electro mechanical switches. The time source is a drop in "module" comprising a 240V 50cps synchronous electric motor with gearbox giving one RPM. Attached to this is a cam which activates a switch that looks to have been taken from a relay similar to those used elsewhere in the clock. This gives one pulse per minute. The rest of the mechanism is built from relays and uniselectors and counts minutes, tens of minutes and hours. These are displayed in two rows of lamps, the top row being hours (1 to 12) the first five lamps of the second row being tens of minutes and the remaining ten lamps being minutes (0 to 9). Further sophistication (complication) is found in the alarm and reset operations. The calendar mechanism This is entirely mechanical. Every 12 hours a lever is pressed and this advances the day dial, e.g. A.M. Mon advances to P.M. Mon. There’s also a date dial and a month dial. The month dial has a cam to set the number of days in the month. February has 28 days on the cam, but every 4 years this is advanced to 29 by an extra lever pushed into place by an extra wheel that advances every 6 months and completes one revolution every 4 years. A nice touch!"
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VJ Fader is a video performance artist based in Los Angeles who is trying out the MSAFluid technology that was created by Mehmet Akten. The effects are very soothing. Thanks VJ
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In the past post about the Fireball V90 CNC Router the assembly of the actual router was shown. This time you will see how to make the motor controller to drive the CNC machine. There are many options to choose from. I decided to purchase the motors and control electronics from Probotix since they know what goes best with the Fireball V90. The build details below describe the first of two build phases. All that has been done so far is enough to operate the machine. I used an old computer case for the driver controller, this gave me tons of room to add additional components in the future and also saved me a few bucks in the process. I also purchased additional components which will be added to the controller in the future. These future enhancements will include adding a supply current meter, volt meter, limit switches, a remote e-stop, temperature sensors and a remote control device. There are also lots of additions that are being developed for the system, these are being made by Probotix as well as system users. A good example of a user contribution are these products that Mike Phillips from MCPi have put together. Keep your eyes open for some cool projects that this CNC machine is sure to have a part in soon!
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This Pedal Powered Air Gun must be tons of fun, no more pedaling the stationary bike in front of the TV. Get on this bike, burn some calories and shoot some targets! Check out the nice re-use of a spent shotgun shell as the projectile for this gun. Bill we need to see a video of this thing in action. "The device is made from an exercise bicycle a neighbor up the street was throwing away, the compressor head from a small garage air compressor, and enough PVC to make something almost like a spud gun. The rear is connected to a 1 inch electric lawn sprinkler valve. The projectiles are made from 12 ga shot shell hulls, with the primer knocked out, and the hole threaded for a 1-1/4” ¼-20 screw. Drive the screw in from the front and add a nut on the outside, grind the bolt to a point, and you’re there."
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I remember when taking electronics in college it was mentioned that you could order standard transistors, or you could order matched transistor pairs for high end audio use. A pair of transistors that were matched would work in perfect unison since even devices out of the same batch will have some slight variations. Have a look at the image below for an example of testing a ton of devices only to select 2 pairs of the best matched ones. I had never heard of a passive attenuator before but we all can relate to the eventual problems of an audio system that could use this technology. Typical audio systems use a potentiometer to adjust the audio level, internally there is a wiper arm that moves across a resistive element. When dust and dirt build up inside this device you will have a crackling effect when operating the device. The designer, George Stantscheff also sells them, but at $400 USD I will stick to my more conventional system. Have a look at the full article which includes a schematic to build your own. "The operating principle of the optocoupler is fairly simple. As the intensity of the LED varies, so does the internal resistance of the LDR (resistance decreases with increasing light). So in the case of the Lightspeed Attenuator, we change the volume (resistance) by changing the intensity of the LED. By using a series and shunt combination of optocouplers the attenuator can be configured to produces a constant input and output impedance, regardless of where the voltage control setting is. The following will required to build a Lightspeed Attenuator.
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The RiSE Version 3 robot looks freaky, it appears to be some type of small animal scampering up the pole. The University of Pennsylvania has some cool tech coming out of its Kod*lab. "Unlike RiSE V1 and RiSE V2, this newer version adopted a quadrupedal configuration, and was designed by Boston Dynamics, with input from the RiSE Project consortium. RiSE V3 uses brushless DC motors that increase power density. Coupled with a dramatically different leg mechanism, this robot exhibits rapid climbing (upwards of 22 cm/s) up a vertical surface such as a telephone pole." Via: Technabob
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On Monday we featured the first part of Pager Data Snooping experiment. The video above demonstrates the completion of the experiment where the data is successfully retrieved from the device, conditioned and fed into a serial port, some special software allows a Windows computer to display all the messages that are being transmitted to pager clients. |
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