Building A One-ton Linear Servo

June 7, 2011 by Mike Nathan 13 Comments

one_ton_servo_jack

A while back, [Windell] from Evil Mad Scientist Laboratories wrote up an article for Make Magazine detailing how he built a one-ton, servo-controlled scissor jack for under $100. He dropped us a line to let us know that the project details have been released for free at Make Projects, so we stopped by to take a look.

The project starts out by pulling apart an electronic scissor jack to get access to the solder pads for the up and down buttons. Once wires are added there, a servo is the next victim. [Windell] recommends using an old servo with a busted motor, but you can use a good one just the same. The servo’s pots are replaced with 10 turn pots, and then wired up to a controller board, to which the jack is also connected. Then, to provide feedback to the servo, a string is looped around the top of the jack, which is used to turn the pots added in the previous step.

[Windell] says that the setup works quite well, though we imagine the duty cycle might be a bit short before adjustments are required. Regardless, it’s a quick way to get a heavy load lifted with servo precision.

The Complete AVR Programmer That Fits In Your Pocket

June 6, 2011 by Nick Schulze 13 Comments

We have seen a few very nice and polished AVR based projects from [Manekinen] over the last few years. Now he has just finished his latest project, the µProg, a super tiny complete AVR programmer with a bunch of features. The µProg completely eliminates the need for a computer to program your embedded AVR chips.

The programmer fits entirely behind an LPH7779 graphics display, and accepts any FAT16/32 formatted microSD cards. Some features include, reading, writing or verifying flash, eeprom, fusebits and lockbits, it also shows amusing animations after every operation. The device is controlled with the use of 4 tactile buttons and operates on a couple of CR2032 batteries.

For an amazingly detailed write up including pictures, eagle files and firmware check out his website. The video embedded after the break has a nice demonstration of the µProg in action, showing off a few of the features and animations. You should also check out his PSU monitor and a spectrum analyser

Continue reading “The Complete AVR Programmer That Fits In Your Pocket” →

How To Make A Hand Drill Out Of A Pencil Sharpener

June 5, 2011 by Jeremy Cook 27 Comments

Necessity is the mother of invention, or so they say. [Jason] was in such a situation where he needed to install some safety railing at his grandmother’s house. He didn’t have the necessary tools available, like a drill, so he fashioned one himself out of a pencil sharpener and some fittings and wire that he was able to find.

Although crude, and probably not what one would choose to use if an actual drill was available, this “drill-pencil-sharpener” actually does a pretty decent job of cutting through plywood as seen in the video after the break. Continue reading “How To Make A Hand Drill Out Of A Pencil Sharpener” →

Putting The Flex Back Into The RDS 80 Soldering Station

June 5, 2011 by Mike Nathan 16 Comments

ersa_soldering_iron_fix

[Markus] was looking to upgrade his soldering station, and having had good luck with Ersa in the past, opted to purchase one of their new stations, the RDS 80.

Once he got the iron home however, he was very disappointed to see that while his previous Ersa model used a silicone cable to connect the iron to the base station, his new iron used a stiff, non heat-resistant PVC cable instead. He found plenty of people complaining about the same issue online, but no one seemed to have a fix, so he set off to figure it out for himself.

He thought that he could disassemble the iron and change the wiring out once it was apart, but it seemed that there was no way of doing so without destroying it. Instead he chopped the wire off at the end of the soldering iron, replacing it with a new silicone cable. He did the same thing at the base station end, since he was forced to reuse the proprietary 4-pin plug Ersa decided to use there.

His modifications worked out nicely, and he is now happily soldering away.

If you happen to have one of these soldering stations, be sure to swing by his site to get a closer look at how he swapped out the cable.

DIY High Voltage Electric Field Detector

June 3, 2011 by Mike Nathan 23 Comments

electric_field_detector

Who needs a Fluke high voltage detector when you’ve got one of these things?

Actually, we still recommend a professional high voltage detector for serious work, but you’ve got to like this electric field detector that [Alessandro] recently put together.

The detector works by using a JFET to detect the high impedance electric fields that are generated by high voltage lines. The JFET amplifies the signal while dropping the impedance in order to drive a pair of NPN transistors which are used as a threshold amplifier. Once the voltage hits 3V, an LED is lit, indicating the presence of high voltage near the detector’s probe. A wire-wrapped resistor does double-duty serving as the probe while providing a high impedance path to ground, ensuring that stray charge does not accumulate on the JFET’s gate, causing false readings.

It’s a neat project, and something that can be constructed in no time, making it perfect for beginner electronics classes.

Keep reading to see a quick video of the HV detector in action.

Continue reading “DIY High Voltage Electric Field Detector” →

Turn A Logic Analyzer Into A Signal Generator Using Only Software

May 24, 2011 by Mike Szczys 18 Comments

One thing we learned by watching [Alton Brown] on all of those Good Eats episodes is that a multitasker is way better than a unitasker. [Joost] is thinking along the same lines by taking a fantastic tool and adding a useful function to it. His software project turns a USB Saleae Logic Analyzer into a signal generator.

There are already a multitude of reasons to own one of these fantastic tools. But the ability to use it to generate up to 8 channels of PWM signals is a welcome addition. It is capable of producing frequencies from 1Hz up to 1MHz at a sample rate of 4 MHz. It uses the original SDK and doesn’t require any changes to the hardware (we would’ve thought new firmware was necessary, but happily that’s not the case). The one caveat is that right now this only works with Windows machines running the .NET version 3.5 or higher. It looks like an MSI installer package is all that’s available for download so the thoughts of easily porting this to other operating systems have been dashed unless [Joost] decides to share his source code.

Edit 7/12/2016: [Joost]’s webpage is down, but he moved it to Github.

Serial Port JTAG Programmer

May 22, 2011 by Mike Szczys 9 Comments

If you’re planning to do some hacking with CPLD or FPGA chips you’ll need a way to program them. JTAG is one of the options and here’s a cheap method that uses the serial port (translated).

This method requires only four signals (TDI, TMS, TCK and TDO) plus ground. But the problem is that an RS232 serial port operates with 12V logic levels and the JTAG side of the programmer needs to operate with the logic levels native to the device you’re programming. Commercial programmers use a level convert IC to take care of this for you, but that doesn’t mesh with the cheap goal of this project. Instead, [Nicholas] uses Zener diodes and voltage dividers to make the conversion. There is also an LED for each data signal to give some feedback if you’re having trouble.

You can use this along with a programming application that [Nicholas] whipped up using Visual Studio. It works well via the serial port, but he did try programming with a USB-to-Serial dongle. He found that this method slows the process down to an unbearable 5-minutes. Take a look, maybe you can help to get that sloth-like programming up to a manageable speed.

[Thanks Alex]