A few years ago I built a Monster UPS using an RV Inverter/Charger and two golf cart batteries. Seeing as how I have a lot of extra golf cart batteries just hanging around, I upgraded it to use eight GC2 batteries (that’s 720 AH x 12 volts, or 8.6 kWh when new). Because more is better, right? (Except for the 500 lb system weight…which is probably getting close to the capacity of the steel cart I’m using to make it semi-mobile.)
I have mounted the parallel port break out board inside the enclosure of my ScanTek 2000 (Denford Micromill). I routed the parallel port cable out to the previous DB25 (RS-232) outlet on the case and sealed up the back.
With the built in wire management trays, the job looks almost professional…except for the fact that I used a triangular piece of 1/4″ acrylic scrap I had for the mounting plate, so I had to orient the break out board at an angle. But since it’s inside the case, nobody can see it anyways. 
Outside the case, the only visible difference is that I took off the black “RS-232” sticker that used to live next to the DB-25 connector. Continue reading
Summary: I drove my truck 46 miles on one charge (and had some juice left over).
When you have an electric vehicle, everybody wants to know how far it can go.
I typically tell them “19,800 miles so far.”
But then you have to answer their real question, which is “What’s your range on a single charge?”. If you have a commercial EV like the Leaf or a Tesla, you can just refer to the EPA range figure for a nice apples to apples comparison. But when you have a conversion EV, the number is unique to your particular vehicle, motor, controller, battery pack and testing methodology. (And changes as the pack ages…)
I used to know the answer to that question for my truck with a (new) lead acid battery pack (“25-30 miles without killing the pack”), but I haven’t fully characterized the trucks’ power usage and range with the new (lighter weight, more powerful) pack made up of Nissan Leaf cell modules. My truck is heavier and has more air resistance than a stock Nissan leaf, the motor/controller is slightly less efficient, and the (big fat!) tires have quite a bit more rolling resistance. I figured “half the range of a Leaf” would be a good ballpark estimate.
I was given this 5 gallon portable air tank, but you can purchase them from Harbor Freight or Northern Industrial in the $30-35 price range. It is filled with a car tire (Schrader) valve and has a built in pressure gauge, overpressure release valve and car tire fill hose.
I have a small garage compressor. It is a 1.3 HP compressor that provides 2.4 SCFM at 90 psi, which is reasonable if you need to blow stuff off, drive the occasional air wrench, or do some light spray painting, but not a very high output. It only has a 1.5 gallon tank, so if you start using a lot of air it doesn’t last long.
My plasma cutter wants 6 SCFM, which is more than the compressor can provide, but I only need about a 10% duty cycle. (make a cut, then move the metal, re-clamp it, set up a straightedge or jig for the next cut, etc…)
I bought some items in the tools / air-compressor isle at Home Depot to add the ability to attach the 5 gallon tank between my small compressor and the plasma cutter using standard quick connect fittings. The air fill hose that comes with the tank is mounted with a standard 1/4″ NPT connector, so all I need to buy was a T, a ball valve, a quick connection package, and a male to male adapter. I had to screw the pressure gauge 90 degrees to get room for both ends of the T.
One end of the T goes to the ball valve and the quick connect fill connector. This side is connected to the air compressor and allows the tank to be filled by my small compressor and to act as an air buffer. The other end of the T goes to the female quick connect adapter, allowing me to plug in any standard QC hose. I included the ball valve so that I could close it and disconnect the tank from the compressor and have it remain full, although primarily I’ll be using the tank “in-line”. The cost of these parts was $15, or about half the cost of the tank if you bought it new.
Here is a video:
I’ve been collecting sheets of material. Acrylic sheets, plywood, insulating foam, etc. Currently the garage doesn’t have any place good to store large sheets of material, so I decided to build something up in the attic.
I started with two upright boards (made from scrap wood I had laying around).
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I used to own two FOSCAM cameras, which used to (mostly) work with Linux. They would ask you to install a proprietary plugin (that doesn’t work in Linux) to view their camera feed, but if you selected the MJPEG feed everything would still work with Linux or other OS’s without installing the plugin. (And you could manage them via the web interface with no problems.)
HOWEVER, after their latest firmware upgrade, their web management interface will NOT allow you to log in unless their proprietary plugins are detected. This means that you can not manage them from Linux. I asked them for a way to downgrade the firmware and they refused.
These cameras are now useless for use with Linux, and they are also useless unless you are willing to install foscam’s proprietary software on our (windows/mac) system. And if you trust FOSCAM to put code on your computer, you should read this: Bug Exposes IP Cameras, Baby Monitors or look here: Foscam : Security Vulnerabilities and reconsider letting them install software on your computers.
And then there are things like this:This is Why People Fear the “˜Internet of Things’
Every so often a project of mine gets picked up by websites like Hackaday. This one is more likely to be collected on pinterest (that’s where the inspiration came from, my wife showed me a picture, and off I went).
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When I purchased the ScanTek 2000 Scan Mill (A rebranded Denford Micromill) from a surplus supply house, the spindle motor was at an odd angle and the drive belt had frayed (probably due to the angle).
When I took the motor off, it was clear that the problem was a bent bracket.
Since I needed to purchase a new drive belt ( Sherline PN 40040 – $9) I decided to just buy a new Sherline spindle motor support bracket (PN 40020 – $7 ) at the same time because it was relatively inexpensive.
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In part 1 of this series I showed how to get the X/Y/Z steppers moving. In part 2 I hooked up the home and estop switches. In part 3 I got the spindle go relay working so that I could turn the spindle on (at full speed) or off. In this post, I will show how to get PWM speed control of the spindle working.
The Balfor NextMove ST card has an output (SOUT & SGND) line that provides an isolated 0-10 volt signal (at low current) suitable for controlling a spindle motor driver board. (0 volts is stopped, 10 volts is full power) In the bottom left of the picture below you can see the small blue and red wire leading away from SOUT & SGND.
It does this by using a DC/DC converter (NME0512D) to provide an isolated (floating) 12 volts, referenced to the SGND connector. A TLC272C OpAmp chip integrates a PWM signal (taking into account an offset adjustment from R35, the boxy blue variable resistor near the SGND/SOUT pins) into a 0-10 volt signal.
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Now that I have the hardware in place, I’m working on the software side of things. I installed and configured LinuxCNC to control the Mill. (Mach3 was easier to get set up and running initially on the trial license, but they do require you to run windows…and the GUI is a bit garish.) In this video you can see the mill cutting out a circular pocket (in the middle of the air, as I’m testing CAM software, software limits, etc as well.)
You might notice that the belt has been removed between my spindle and spindle motor. When I purchased the machine the spindle motor was at a slight angle, which I traced to a bent spindle motor bracket. As a new bracket costs under $7, I decided to buy a new one instead of trying to bend my existing one back into shape. The replacement bracket appears to be machined slightly better overall anyways. Until it arrives, I don’t have the spindle hooked up.
