DIY Auto Fish Feeder Feeds Fish Automatically

October 14, 2014 by Rich Bremer 28 Comments

[Brian] has a fairly large 400 liter aquarium and loves the fish that call it home. Unfortunately, sometimes life gets in the way of keeping those fish fed on a regular basis. There are automatic fish feeders out there on the market and [Brian] gave one a try. Although it worked, it dropped one huge clump of food in at a time (rather than sprinkling it in), the food hopper held a very small amount of food and the unit drained a new set of batteries in less than a week. Fifty euros were spent on purchasing that auto feeder and in the end it wasn’t any more convenient than just feeding the fish.

Faced with a tough decision on whether or not to buy another product he may not be happy with, [Brian] decided to make his own automatic fish feeder system out of parts anyone can find lying around the house. The main housing is a small Tupperware bin, inside of which 3 pieces of plastic were glued together to make a v-shaped hopper. The fish food is loaded into the hopper and as it falls to the bottom it meets a reverse-spinning drill bit that acts like an auger, pushing the food out of the container. The drill bit is powered by a small stepper motor connected to the drill bit by an improvised coupling made from a silicone sealant cap!

The control system is an Arduino and a stepper motor driver chip. Through trial and error [Brian] figured out that 100,000 half steps of the motor dumped a good amount of food into the tank. The drill bit delivery method even sprinkles the food nicely for total fish enjoyment. To keep the food flowing at regular intervals, an AC timer unit controls how often the Arduino is powered on and subsequently feeds the fish.

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Robotic Farms Invade Urban Landscapes

October 13, 2014 by Rich Bremer 24 Comments

Now there is no excuse to not have a garden, even if you are located in an urban area. The Robotic Urban Farm System (RUFS for short) solves the problems of growing many plants in a small area. The system’s high plant density is attributed to its vertical orientation. The entire system is even made from easy to find parts from your local hardware store. The water usage is kept to a minimum thanks to the closed loop watering system. Instead of flowing down into the ground, any excess water is collected and saved for use later.

Plants are placed in holes made in the side of a standard plastic downspout that hangs from a PVC frame, each hole several inches apart from its neighbor. A standard plastic plant pot is place inside each hole and is filled with hydroponic media. That’s right, there is no dirt in this system. Plants will grow happily in the hydroponic media providing they get all the nutrients and water they need.

The potential urban farmer may not be super excited about tending to his crops. This is where the robot portion of the RUFS system comes into play. There are two control systems that work independently of each other. The first is for indoor applications and controls light cycles and circulation fans. The second is a little more complex and controls the watering portion of the system. Not only does it water the plants at pre-determined intervals but it also monitors the pH, nutrient and water levels inside the reservoir. Both these systems are Arduino-based. For extreme control freaks, there is one more add-on available. It’s Raspberry Pi based and has an accompanying mobile app. The Pi records and logs sensor data from the Arduinos and also allows remote updating of the watering and light schedules. The mobile app lets you not only look at current conditions of the system but also displays the historical data in a nice visual graph.

PCB Toner Transfer Method, Now Without The Transfer

October 12, 2014 by Rich Bremer 47 Comments

A common way to create a custom PCB at home is to do what is called the Toner Transfer Method. In this process, the trace layout of the board is printed out on a piece of special toner transfer paper that allows the ink to come off in the following step. The toner transfer paper is then put print-side-down on a copper clad PCB blank, heated and pressed with an iron. The heat and pressure from the iron transfers the toner from the paper to the copper. The exposed copper then is chemically removed, the previously applied toner protects the copper in the pad and trace areas. The toner is then removed using paint thinner.

That is a long process with many critical steps. [mlerman] wondered why no one was printing the toner directly to the PCB. He has been tinkering with printing directly on PCB blanks for 4 years now. He’s made hundreds of boards over that time and can now make a PCB in under 15 minutes.

The obvious route to take would be to modify a current laser printer to accept the much-thicker-than-paper PCB boards. A few printer models were tried but [mlerman] feels the Lexmark E260 works the best due to the cost, internal mechanical components and an easily modifiable manual feed system. There is also a Local Printer Utility that allows the majority of the printer parameters to be adjusted.

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Bench Top Drill Press Converted To Milling Machine, Mounted To Lathe

October 12, 2014 by Rich Bremer 22 Comments

Milling machines are nice to have around for precisely drilling holes or removing unwanted material from a part. However, they can be expensive and may not get a lot of use, two reasons why a mill purchase may not make sense for a home shop. [David] didn’t need a mill, he wanted one and he didn’t want to spend a lot of money. He did have an old bench top drill press and a lathe in his shop and thought it would be a good idea to combine them them into a DIY Milling Machine.

The problem with just throwing a milling bit in a drill press and trying to mill metal is that the drill press spindle ball bearings are not made for radial loading. [David] knew this and replaced the stock ball bearings with angular roller bearings. These new bearings would require an axial preload applied to keep the spindle in place. This was done by machining threads into the spindle’s shaft and adding a nut to secure and preload the new angular roller bearings.

[David] did not have an XY Table to donate to the project so he decided to mount the drill press to his lathe and use the lathe axes to move the work piece around underneath the mill. Thick plate steel was welded together to form a hefty bracket that bolted to both the lathe bed and drill press column. And yes, the lathe is still functional and the changeover process is simple. To go from Mill to Lathe; the work piece is removed from the lathe’s cross slide and replaced with the lathe tool holder. That’s it!

Overall, [David] is happy with his conversion. He doesn’t expect his project to be as precise or rigid as a proper milling machine but says he has no problem cutting 1mm deep passes in steel when using a 6mm diameter mill bit.

PrintBot prints talcum powder on your floor

PrintBot Prints On The Ground, Uses Talcum Powder

October 7, 2014 by Rich Bremer 27 Comments

Yes, this is a printing ‘bot but it’s not a 3D Printer. Even though it’s called Printbot, don’t get it confused with other products that may begin with ‘Print’ and end in ‘bot’. Printbot is half Roomba, half old inkjet print carriage drive and the remaining half is a small PC running Windows CE.

The whole point of this ‘bot is to draw/write/print things on the floor. No, not in ink, in talcum powder! The Roomba drives in one axis as the powder is systematically dropped in the ‘bots wake. It works one line at a time, similar to how a progressive scan TV displays an image on the screen. The PC on board the Printbot reads 8-bit gray scale images from a USB drive, re-samples the image and outputs the image one line at a time to an external microcontroller. The microcontroller is responsible for driving the Roomba forward as well as moving the hopper’s position and dispensing the powder in the correct place. Check out the small photo below. That black and white strip is not there for good looks. It is part of the encoder positioning system that is responsible for communicating the location of the hopper back to the microcontroller.

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CNC Router Converted To 3D Printer

October 7, 2014 by Rich Bremer 22 Comments

3D Printers have come down significantly in price over the past few years. Nowadays it is even possible to get a 3D printer kit for between $200-300. It’s arguable how well these inexpensive printers perform. [Jon] wanted a printer capable of quality prints without breaking the bank. After researching the different RepRap types that are available he concluded he really wasn’t up for a full machine build. He had previously built a CNC Router and decided it was best to add a hot end and extruder to the already built 3 axis frame.

The CNC Router frame is made from aluminum, is very rigid and has a 2′ by 2′ cutting area. All axes glide smoothly on THK linear bearings and are powered by NEMA 23 motors driven by Gecko 540 stepper drivers. The router was removed from the machine but the mounting bracket was left on. The bracket was then modified to hold the extruder and hot end. With 3D Printers there is typically a control board specifically designed for the task with dedicated outputs to control the temperature of the hot end. Since [Jon] already had the electronics set up for the router, he didn’t need a specialized 3D Printer control board. What he does need is a way to control the temperature of the hot end and he did that by using a stand-alone PID. The PID is set manually and provides no feedback to the computer or control board.

[Jon] used liked Mach3 for controlling his CNC Router so he stuck with it for printing. He’s tried a few slicers but it seems Slic3r works the best for his setup. Once the g-code is generated it is run though Mach3 to control the machine. [Jon] admits that he has a way to go with tweaking the settings and that the print speed is slower than most print-only machines due to the mass of the frame’s gantry and carriage. Even so, his huge whistle print looks pretty darn good. Check it out in the video after the break…

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4 Axis CNC Foam Cutter Sports A Unistrut Frame

October 6, 2014 by Rich Bremer 29 Comments

CNC Foam Cutters are capable of cutting out some pretty cool shapes that would otherwise be extremely difficult to do. They do this by pulling a heated metal wire though a block of foam. Electrical current passing through the wire heats it up causing the foam to melt away, there is no dust and no mess to clean up. [batchelc] decided to make his own large-scale CNC Foam Cutter and took a lot of photos along the way.

Since machine is 4 axis, meaning both sides can move forward/back and up/down independently of each other, tapered shapes are possible. One example where this would be helpful is cutting wings that are swept or have different profiles at each end.

The main frame of the machine is made from Unistrut and measures a whopping 60 by 60 inches. Subtract the size of the mechanical components and the cutting area ends up being 48 by 42 and 22 inches high. The foam sits on an MDF bed, gravity is the only method of holding the foam down during cutting. The wire doesn’t actually touch the foam so there is no force applied to cause it to move. The hot wire moves slowly and melts the foam just a few thousands of an inch in front of the wire resulting in no contact between the two.

Both axes on each side are driven by 1/2-10″ lead screws supported by bearing blocks on both sides. The longitudinal axes smoothly traverse the length of the machine by means of skate bearings that ride on the Unistrut channel itself. The vertical axes have a plastic bushing that slides along a round shaft.

The control portion of the machine is a HobbyCC FoamPro kit that came with the 4 axis stepper motor control board and 4 NEMA 23 stepper motors. GMFC software is used to both generate the g-code and send the commands to the stepper motor control board.

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