GRBLDuino Shield CNC Controller

Over the past few days I’ve been designing a Arduino Uno CNC controller shield.

My requirements were pretty simple:

  • GRBL 1.1 compatible
  • Pin compatible with Pololu DRV8825 drivers
  • User replaceable stepper motor drivers
  • Screw terminals for connections
  • E-Stop, Abort, Hold, and Resume buttons
  • Probe connection
  • Spindle PWM control
  • User selectable 4th axis function (clone or separate)
  • No SMD packages in the first version

Arduino CNC shields are pretty easy to find (and shockingly cheap) but not many are compatible with the changes in GRBL 1.1. I didn’t want a product that was out of date before I even purchased it.

My design is loosely based on the Protoneer Arduino CNC Shield. I fully support the purchase of the Protoneer product but it is hard to get in the US – available only from his eBay store.

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EDS, Inc LeakSeeker 89

LeakSeeker 89 PCB

EDS, Inc LeakSeeker 89 PCB

Awhile back I was reading through a back issue of Nuts & Volts magazine and came across an ad for the LeakSeeker 89 from Electronic Design Specialists. I was intrigued by the device and searched for a place to buy one, even a used one, but they were nowhere to be found. This led me to contact Dave Miga and order a parts kit. The kit price was reasonable for not having to source parts and deal with minimum order quantities plus he is the only source for the programmed PIC microcontroller.

LeakSeeker 89 Auto-ranging Fault Locator PCB

The LeakSeeker 89 locates the exact spot on the PC board (to within a fraction of an inch) where a shorted or leaky component is bringing a power supply bus or data line to ground. It is the only locator that can locate defects from zero to 300 ohms with no loss of resolution. It can even find active shorts that a DVM won’t even show. The high GAIN mode can locate shorted components on multi-layer boards with ground planes and a power layer.

After ordering the parts, Dave emailed me the bill of materials, enclosure overlays, Gerber files to get the PCBs manufactured. Not wanting to pay the suggested $100 for 5 PCBs, I invested some effort into converting the Gerbers into standard format and getting them ready for manufacturing at a place like EasyEDA or OSH Park. EasyEDA was the cheapest and OSH Park, though high quality and quick, was expensive.

So, having the parts and PCBs arrive, I began construction. Keep in mind, there are no assembly instructions at this time. (I’ll update here if I develop some.) It took me about two hours to get a finished product minus the enclosure (I’m waiting for it to arrive).

Assembly is pretty straightforward with typical through-hole components. The only issue I had was installing the BR2 rectifier backwards since it is not obviously marked (the square pad is the + pin).

I haven’t had an opportunity to use the LeakSeeker yet, but, after some basic tests, it appears to function.

The next steps are to get the case, drill it for the LEDS, switches, and probes, then make and apply the overlays. Dave provides all of the dimensions needed to ensure a quality completed product.

Here is the finished product in a poorly labeled case:

Finished LeakSeeker 89

Finished LeakSeeker 89



Parts Kit: EDS, Inc – last paragraph on the page explains how to order. You can also email directly:
PCB: These are for sale through a few outlets. The best price will be at the Eccentric Workshop store, but they are on Tindie and eBay.
Enclosures: OKW Tenclos Pulpit 590.9 – these are imported from Italy and you must email the company to order (I worked with Jeff Duchess). If there is enough demand, I may stock these.


Order from OSH ParkI sell on Tindie

Parachute Bag

Real Parachute Bag and Reproduction

Real Parachute Bag and Reproduction

The parachute bag is based on a product of the same name from the Portable Product company. It is a six compartment bag with drawstring closure. I got turned onto them years ago by Jimmy Diresta and have found a few on eBay but they are getting more expensive and harder to find. The bags are great for storing hardware such as nails and screws or anything else fitting in the pockets. I use one of mine to store an assortment of adhesives, another has various screws, and another holds nails.

The realbag is made of cotton duck canvas heavier than the 9 oz I found. I’d suggest using a #10 or #12 cotton duck canvas. For durability, it may be a good change to incorporate a leather bottom like some canvas bags have.


3 panels 7″ tall and 11″ long (dividers)
1 panel 7 inches tall and 32 1/2″ long (outside)
1 panel 11″ circle (bottom)
48 1/4″ grommets (4 in every section)
3 pieces parachute cord 36″ long

1. Cut all pieces to size.
2. Mark rectangular panels along long dimension on one edge at 1/4″ and 1 1/4″ from the edge for the top hem. Mark 1/2″ on all other sides of rectangular panels and 1/2″ in on circular panel as sewing guides. Mark 5 1/4″ inch increments along inside (opposite hem) of 32 1/2″ length, being sure to start at 1/2″ mark from previous step. These are the sew lines for the interior dividers. Fold the bottom circle in half an then into thirds to make 6 creases where the interior dividers will be sewn.
3. Fold, iron, and sew top hems on all panels. The finished hem should be 1″ wide with 1/4″ folded under.
4. Once all top hems are sewn, align all three small panels and mark middle of 11″ dimension of divider panels as a sewing guide. Sew along this line to join all three small panels together to form the interior dividers.
5. Sew the outside panel ends together with the hem facing out. Sewing 1/2″ in from each end will ensure the ring formed will join to the circular bottom.
6. Working inside out, align sewing alignment marks on the bottom edge of the outside panel and the bottom circular panel. Sew around the full circumference to form a pouch or bucket.
7. Align ends of dividers with the marks on the outside panel. Sew along the alignment lines down sides and across the bottom to the center. Repeat for each divider segment.
8. Each section gets 4 evenly spaced grommets in the top hem to allow for threading the drawstring closure.
9. thread about 1/4 of the parachute cord drawstring from the center out each side through the grommets. There will be loop in the center to form a handle and a knot secures the end after the last grommet. I like to tie an overhand know around all of the lines to keep them together.

Light houses

So far, I have made three sizes of faceted light houses and one size of round light house. The

Small Lighthouse Size Comparison

three faceted ones were lit electronically with an LED  controlled by my lighthouse beacon hardware and the round one was lit with a tea light candle. The smallest one about 5″ tall and the largest is 18″. The mid size stands at 10″ tall.


Building a light house starts with a roll of copper flashing from the home improvement store, some hand tools, some reference photos, some calculating, and a bit of determination. I initially though the facets would be easier to construct than trying to smoothly roll two cone shapes and have them fit together nicely. Turns out calculating and rolling the cones was much easier than getting all of the pieces lined up just right and held together for soldering.

I wasn’t quite sure of the shapes and dimensions involved so all of the light houses were built in card board before working in copper. This allowed me to play with the shapes and angles before getting committed to the more expensive and harder to work material.

Once the shapes were figured out, it was a matter of cutting six identical pieces, a top platform, and a roof with tin snips. The pieces needed to be fairly accurate and fit together well or there would be gaps in the seams on the final project.

Of all stages of assembly, bending the hexagonal pyramid to form the roof portion was the most difficult. There isn’t much room to work inside one the bend is started so it just takes a bit of time and some careful plier and hammer work. Because the round model was lit with a candle, the top piece had to have a grid of vent holes drilled to allow heat and smoke to escape. I found it best to drill the holes after bending the piece to shape and soldering it together. Doing it the other way would mangle the point a bit since there was not much support left.

The body itself is bent roughly to shape to check fit. High spots in the seams are trimmed to get a tight joint. Once everything is fitting well, the pieces are taped together to make soldering easier. Some care must be taken to keep the flame and heat off the tape or it will burn. I generally solder a spot at the bottom of each seam to get everything started then work around adjusting the shape. Once the shape is nearly right, I do a small section on each joint at the top, right before it flares out for the top platform. I keep the top flared section until last as it requires the most adjustment to get it fitting well.

I don’t have pictures of construction of the round lighthouse, but it is similar to the faceted ones. It is made of three rolled pieces and one flat: the body cone, the transition cone, and the lid cone. The top platform is marked after the body is assembled by turning it upside down and tracing around onto the copper sheet. This ensures the platform is a good fit to the body.

Once the top platform is soldered in place, the only soldering left to do is for the railing. The railing and posts are made from standard electrical wire. The middle and large size use 12 gauge wire. Each upright is soldered into place then the rail is bent roughly to shape. I adjust it as I work around it soldering to each post.

The lighthouses are finished with a thorough wash to remove all of the flux from soldering as well as the residue from the masking tape. I scrubbed them using top to bottom strokes with a fine scotchbrite pad to give the surfaces a uniform brushed look.

The lense varies based on what is at hand. I have used plastic tubes and various jars. For my first one, I cut the bottom off the jar and glued it down. This didn’t work very well so now I glue the lid to the top platform, screw the jar in (upside down now), then set the top of the light house in place. Once I know how the top and jar need to be aligned, I tack them together with a few drops of hot glue and firmly attach with E-6000 or epoxy.


The beacon was designed to use a pulse width modulation (PWM) signal to vary the brightness of the LED. This allowed for an even and gradual fade up, flash, then fade down in order to simulate a light spinning inside the light house. The hardware was the same for each: a 1″ square ProtoBoard from SparkFun with various components. The work is done by the PICAXE microcontroller. A switch is available to determine continuous or flash mode and the flash mode is disabled if the ambient light is too bright. This controller was the same in all three sizes – the battery pack varied to fit within the body. The largest had a 4 AA pack, the middle had a 3 AAA pack, and the smallest could only hold a single AAA cell. These controllers will soon be available through Tindie.