Voltage Regulator Installation & Problems

Problem #1:
Do not appear to be "regulating" the voltage. The voltage changes dramatically with a change in RPM of the engine.
Problem #2:
Extreme vibrations from the engine cause the heatsink to bend the switching voltage regulator's pins clear off of the board (see pictures). I need to redesign to have a heatsink which secures to the board.

Voltage Regulator for Tecumseh HMSK80 Alternator

Last winter I installed an alternator on my Tecumseh powered snow blower. I did design and build a circuit for the voltage regulator. I also purchased an LED flood light and mounted it to the blower. Here is the long awaited documentation and finishing of last years project!

TruckStar 12-24 Volt LED Flood Light - Clear, Round, 4in., Model# 1492115:

 http://www.northerntool.com/shop/tools/product_200482377_200482377

Claims a meager 1.06A of draw at 14.3VDC. Through 6x 3 Watt LED's it promises an impressive 1350 Lumens. I really like the quality of the unit. It's a solid metal case that's fully sealed. It's also quite slim, unlike a traditional flood light. I paid $59.99. It's regular price is $69.99. I have seen it for as low as $54.99 depending on the sale.

Voltage Regulator
Opted to go with the TI LM2677/8/9 5A Voltage regulator.
 http://www.ti.com/product/lm2677
It was the highest power voltage regulator I could find in a TO220 package. It's also sufficient power for my use. I used TI's special software (Power Stage Designer) to calculate the values of the inductor, capacitors, and resistors I needed for my specific requirements. I especially like that it's a switching regulator, not a linear regulator, so it's more efficient. TI claims up to 92% efficiency. This is the type of chip which could be used in high end computer power supplies.
Here is a generic example provided by TI:

This example gives 5V with a maximum current of 5A.
Using TI's online WebBench tool I input my requirements of 30-40V input and 24V, 5A output. It yielded this circuit:

To run the WebBench tool for yourself, go to the component page here:
http://www.ti.com/product/lm2677
On the right hand side you input your requirements and then click "Open Design". You will need to create a TI account and log in if you don't already have one (it's free).

Formerly I used TI's older software called "LM267X Made Simple" which is a download and install. It lets you choose your chip and also picks out the components you need. Both tools are nice because they generate a BOM for you.

With this schematic I made the following PCB layout:

 And the isolation routing for my CNC router:

There are some problems with the above PCB. Something is wrong with the Tantalum capacitor because I popped two of them almost immediately, however the circuit seemed to run fine without them. I'm not sure of the cause for this as of yet. I also screwed up my routing for the 3 resistors (I wanted to use 2 in series to get the correct resistance). Once I corrected the resistors, I was able to run my LED spot light with this circuit. I am currently in the process of making a 2nd revision of the circuit to address these two problems as well an incorporate a board mounted heatsink.

Quick BOM:
- U1 - LM2877 Switching Voltage Regulator - Sample
- L1 - Inductor 50uH 5A - Digikey #553-1121-ND
- Cin - Aluminum 1000uF 63V 20% - Digikey #P11280-ND
- Cout - Tantalum 47uF 20V 10% - Digikey #478-6065-ND
- Cb - Tracon 2A104K - Already Had
- D2 - Rectifier Bridge 10A 100V - Digikey #GBU1001DI-ND (not shown in TI schematic)
- D1 - STPS2045CT - Power Schottky Rectifier 2x10A 45V- Recycled from old computer PSU

- R1 - 1K
- R2 - 10K

Heatsink Selection:
The switching regulator is very efficient when compared to a traditional linear voltage regulator like the LM7805. The lowest efficiency it claims to get it better than 94%. This means when serving 5A of current at 24V (120W) it will need to dissipate ~7.2W. However, my light only pulls around 0.5A so we're talking much less. Never the less, we need to have a heatsink on our regulator.

How to calculate resistors:
See pages 15 & 16 of the datasheet: http://www.ti.com/lit/ds/symlink/lm2677.pdf
1K is recommended for R1
Using the formula provided, to get 14.4V one should use a 10.9K resistor for R2.

If I have made an mistakes above, please let me know and I will correct them. I hope this helps some people.

7x Tailstock Cam Lock

This was my first complex project and I was learning many different machining processes in order to complete it. The hardest was to make the actual cam piece. Additionally, I attempted to do the project with easily obtainable, local, hardware store stock & pieces.

One overlooked piece is the bottom plate that slides in the lathe bed way. I have yet to see an aftermarket cam lock kit that includes an upgrade for this. They just use the existing plate which is prone to bending after regular use.

 This piece is the piston through which the cam turns. The bottom of the piston has a hole drilled and tapped to attach the bottom plate. The piston slides up and down inside of the main housing.
 The top is threaded for a 1/2" bolt.

 Main housing made of out of ?" hex stock. Bored ?" for the piston.
Piston inside of housing.

 1/2" bolt threaded into the piston. The bolt will join to the bottom plate.

Here the bottom plate is attached to the bolt and piston. The 1/2" drill bit is through the housing and piston where the camshaft will go.

Two pieces of bar stock are welded together to form the bottom plate.

The head of the nut had to be shaved to be flush with the plate.

Unlocked and then locked positions of the lever.

The camshaft dismantled. It uses two E-clips to keep it in place.

Upgrading 3020 CNC Router Cables & Connectors - Part 1

Why?
- EMF/EMI
The spindle is controlled using PWM and a high voltage. This can induce currents in the other wires locates close by.
- Low Quality Wire
CNCs see thousands...millions of repetitive motions. The wires will break at some point no matter how good. It's well known with these units that they ship with low grade wire that can have breaks after only a few hours of machine operation. I'm going to upgrade to wire/cable that is specifically designed for use in a CNC machine.

Cable Selection:
McMasterCarr - http://www.mcmaster.com/#catalog/119/802/=m38xy7
Manufacturer - http://www.igus.eu/iPro/iPro_01_0013_0021_GBen.htm?c=DE&l=en
Description:

• The bodybuilder of the wire world, this cable never gets tired of flexing. It has stranded copper conductors and is often used in cable chain and track for robotics, CNC machines, and material handling equipment. It has one green/yellow ground wire, unless noted. CE approved. Maximum continuous length is 100 ft. Note: The total number of conductors includes the ground wire.
• Shielded cable eliminates electromagnetic interference (EMI).
• 300-VAC Cable
• Has black insulated conductors with white sequential numbers.
• Shielded cable has tinned copper braided shielding.
• Standard—Good for general use; cable withstands periodic exposure to most oils and fluids. It has PVC-insulated conductors surrounded by a PVC jacket. Temperature range is 23° to 158° F. Passes FT1 vertical flame test. UL recognized and CSA certified.
• Oil Resistant—Handles continuous exposure to oil and fluid. It has TPE-insulated conductors surrounded by a polyurethane jacket. Temperature range is -31° to +176° F. Passes FT1 vertical flame test. UL and C-UL recognized.
• Heavy Duty—Made to last over 17 million high-speed cycles. It's oil, abrasion, and chemical resistant and has TPE-E (thermoplastic elastomer) insulated conductors surrounded by a polyurethane jacket. Temperature range is -40° to +194° F.

Required Cable Lengths: (approximate)
X-Axis -
Y-Axis - 26" or 65mm
Z-Axis -
Spindle Motor -

Total Length Required:

Cable Track:
McMasterCarr - http://www.mcmaster.com/#catalog/119/1531/=phqkmp
Manufacturer - http://www.igus.eu/iPro/iPro_01_0002_0002_GBen.htm?ArtNr=06.30.028.0&c=DE&l=en&aeartNr=060.30.12PZ
Description

• When space is tight, you need low-profile carriers. Snap-together links make length adjustment quick and easy. Join lengths by hand; use a screwdriver for dis-assembly. All are black glass-filled nylon. Operating temperature is -40° to 266° F. Compatible with this style of Igus carriers.
• Feed-through carriers require the cable and hose to be threaded through the entire length.
• Mounting brackets are made of black glass-filled nylon and have a built-in plate for strain relief. Fasteners for mounting the brackets to the surface are not included.

The lower, main track, requires capacity for 3x cables (X-axis, Z-axis, & spindle) while the upper track requires capacity for 2x cables (Z-axis & spindle). Depending on your spindle's current draw, you may find it necessary to double up on the wires you use (2x 18AWG for positive and 2x 18AWG for negative).

Length Lower Track:
Length Upper Track:

Connectors:

These obviously match the new panel I made in a previous post. They are decent quality and are definitely over kill for this setup. Best of all, they are metal, so I can ground them. I connected the shield of the wire to the connector itself so the entire cable's shield is grounded. I have not yet found optimal connectors for the stepper motor end of the cables.

Installation:

2" Wide x 1/8" Thick piece of flat stock cut to length. Drilled and tapped for M3 screws.

You could use a piece of angle bracket from a local hardware store. I used a piece of scrap aluminum from a power supply frame that I cut to size. I drilled and tapped the side arm of the CNC.

The tightest configurations looks to strain the cables.

So I gave it some more length even though it will not exactly be compact. Now the cables are nice and flat. Also there is less strain on the chain.

Final complete assembly of the primary cable chain. X, Z, & Spindle cables are run through it.

I will do another post (Part #2) on installing the secondary cable chain for the Z and Spindle cables.

Craftsman vs. Black & Decker Cordless Li-Ion Screw Driver

Craftsman 4 volt Cordless Lithium-Ion Screwdriver with Case and 20 pc. Bit Set

http://www.sears.com/shc/s/p_10153_12605_00911398000P?vName=Tools&cName=Portable+Power+Tools&sName=Power+Screwdrivers+%26+Screwguns

Price $39.99

Features a 2-speed gearbox, a 1/4-inch quick-release hex collet chuck and integrated LED worklight, this cordless screwdriver from Craftsman has the power and features to get the job done. Includes charger, bits and case. Wt. 3.25 lbs.
4.0 volt lithium-ion battery pack provides power and longer run time
Two-speed gears (200 rpm / 600 rpm) allow you to match speed to job application
1/4 in. quick release collet accepts standard nut/screwdriver bits
Adjustable (24-position) Torque Clutch allows selection of proper driving torque needed for various jobs
Automatic Spindle Lock automatically locks collet to allow manual tightening if batteries are not sufficiently charged
Integrated Worklight provides direct light source to work area

Black & Decker VPX1101X Li-Ion VPX 7-volt Screw Driver

http://www.amazon.com/Black-Decker-VPX1101X-Li-Ion-7-volt/dp/B000UMJJ3C

Price $24.99

2-speed transmission: 0-195/0-650 rpm
1/4-inch hex shank Quick Connect collar
7-volt operation with one VPX Li-Ion battery (included)
Weighs 2.6 pounds

Tool Project Centers & Work Carts

So I purchased a lathe a while back that came with a crappy little Craftsman tool chest. It was bolted to the top with a piece of plywood as a top work surface.

At work I have been eying a very nice Westward project center, however, at $590 it is WAY over priced for what you get.
http://www.grainger.com/search?searchQuery=1FEF7
It has a nice galvanized top and light as well as power outlets. Not to mention the pegboard back.

Grainger also sells a unit without the backboard for $354. These units DO have ball bearing slides. As it turns out, the Westward units are made by Waterloo which is the same company that makes Craftsman units.
http://www.grainger.com/search?searchQuery=1FEF6

Waterloo manufactures a lower quality unit for Craftsman based on the same design. The Craftsman unit sells for just $149 (regular $199), but lacks ball bearing slides.
http://www.sears.com/shc/s/p_10153_12605_00959496000P

I have used the above unit before and after a while the non-BB slides make it useless. So it is worth getting a unit with stronger ball bearings. For $200 I feel I should be able to get a BB unit! You loose a lot of features though on the two units above over the unit I first mentioned. The features lost are the ones that are most important too me. So my idea is to get a quality bottom tool cart/chest at a good price on sale and convert it to the unit on top for a total price of $200-$250.

On eBay I managed to find a discontinued accessory to the Craftsman tool cart which would allow one to add the backboard and light to your basic model.
Check out this post for what I ended up doing:
http://georgestone72.blogspot.com/2012/12/lathe-workstation.html

Review of Project Enclosure (3x2x1")

Radio Shack

Custom ABS enclosure for custom electronics projects.

Project Enclosure (3x2x1")

Great Little Box

sirhannick Chicago, IL 2/3/2009

5 5

Pros: Rugged
Describe Yourself: Power User
Primary use: Business

I use these boxes to enclose a lot of my prototypes. One down side is that there were not detailed internal dimensions supplied. No big deal though, I just grabbed the caliper and drafted up a perfect PCB to fit inside. I wish Radio Shack sold matching PCBs. Also, they should offer a downloadable CAD file of the box. I also made a template for PCB123 to design PCBs specifically for this model box.

Replacement Rear CNC Panel for CNC Controller

The original panel is made out of very thin sheet metal that bend easily and is not very rigid. The use of space is not very optimal either.

The panel was machined with the router into1/8" thick Delrin (Acetal Resin) plastic. I bought a 4" x 12" piece for a mere $6.69 from McMaster-Carr (P/N 8739K15). I will probably be doing the front panel over in the same material.

I used a TiCN-Coated Carbide End Mill, Two Flute, 1/8" Mill Diameter, 1/8" Shank Diameter which I got from the same place for $13.47 (P/N 2416A17) to do all the cutting. It was amazingly sharp and was able to cut at very high feed rates.

 

I added an additional for a future axis, limit switches, or other i/o. "Military" grade connectors are more like military style, but they are much better quality than the original connectors. I paid $33.11 for all 5 connectors shipped from China. One key thing is that the panel side connectors have female pins so that if the unit is turned on, without servos & motors connected, the chance of shock is lower.

I had to relocate the PSU slightly to accommodate everything. Nothing major, just drilling new holes.

I may consider posting the AutoCAD drawing of the panel so that others can make it along with the G-code. Let me know if there's demand out there by posting comments.

Review of Radio Shack Arduino Enclosure

Originally submitted at RadioShack

Works with Arduino UNO and Mega boards

Durable and can be stacked

RadioShack® Enclosure Project Skeleton Kit (Two-Tray)

High Quality but lacks Compatibility

By sirhannick from Barrington, IL on 7/8/2013

2out of 5

Pros: Quality construction, Rugged, Modular
Cons: Incompatible, Fittment
Best Uses: School project, Prototyping
Describe Yourself: Power User
Primary use: Personal
Was this a gift?: No

Typo in the manual where the rivets are referred to with the wrong part number. Quality if the components is very good, but I'm not happy with the compatibility. I am using an Arduino UNO R3 and have two genuine Arduino shields. Neither the motor shield nor Ethernet shield fit correctly right out of the box. There are not enough adjustments for height of the plastic panels. I like the modular design, but if no shields fit, what's the point? I will probably 'mod' the enclosure and make it work better. There should be a list if compatible shields as well as some assembly ideas for other ways to put it all together.

(legalese)