Triple barrel potato cannon

Well, this clearly qualifies for artillery of the week. This three barrel potato gun uses electronic injectors to deliver propane to each of its three champers, ignition coils and spark plugs for ignition, and the entire unit, including pan and tilt control is controlled through PIC micro controllers by a gaming joystick.

Triple barrel potato gun

The video has a ton of information on the device, but unfortunately only shows one shot, but if that’s not enough for you, you can make your own with the provided instructions*. I bet we’ll see more video of this potato gun sometime in the future.

* Check local laws regarding high velocity food products, and don’t blame me for the resulting accidents, lawsuits or potato famine.

via MAKE

make, diy, potato, food, potato gun, 3 barrel, atrillery, gun, project

Adventures In Appliance Repair

I have to say that I spent more hours than desired with my head in a freezer today. Worse yet, this is the second time I’ve had to defrost my previously frost-free refrigerator in the past month.

Conclusion: something’s not right in the defroster unit, but what? Since I’m no appliance repairman I was happy to find

The Acme How To Refrigerator Troubleshooting Guide made for easy lookup of symptoms, possible causes, and how to test each part. To complete the picture I found the handy technical data sheet tacked behind the front grill on the fridge.

With that in hand and the faulty part identified I could look up the appropriate replacement part number. Another web search turned up Their site is easy to navigate and search. They have the part in stock and their price is about $10 below Sears, so I ordered it.

Results yet to be seen, but these two sites, and are definitely keepers.

appliance repair, refrigerator, parts, diy

Alan Baker’s Bar Monkey

Pouring a drinkWhile I have written about the Bar Monkey I helped Alan build this winter it’s time to give a better overview of how the whole system works. This is not intended as a how-to but may be of help to folks who are looking to make their own Bar Monkey.

The Bar Monkey is a device for automatically mixing drinks. The concept comes from where you can see several other versions of bar monkeys. Almost all of Alan’s Bar Monkey, including the software, was designed by Alan.

How it works

To dispense a drink with the Bar Monkey all you have to do is place a glass under the tap and choose the drink you want from the display. Your drink is poured from the sixteen ingredients (13 liquors and 3 mixers) contained in the Bar Monkey, all you have to do is add ice and stir! If your drink requires something that didn’t make it into the Bar Monkey (we had trouble piping soda and decided milk products would probably go sour) the software will remind you to add it afterwards.

The Software

Pour a drink

The brains of the system is the Bar Monkey software. Alan wrote this custom Java application which, on startup, reads a text file with a list of drinks and ingredients.

The application has four screens for setup and controlling the Bar Monkey. The first and most important one is the “Pour Drinks” screen where just a single click can pour a complicated drink with up to sixteen ingredients. While the drinks are of different sizes any of them will fit into a standard pint glass with room for some ice. If you’re not sure if you’ll like a drink you can view the ingredients on screen or even use the “Taste Test” option which will pour a small drink, one quarter the size of the normal one, with exactly the same proportions.

The second screen will pour a 1.5 oz shot of any of the ingredients in the Bar Monkey. If your favorite drink is not in our list you can use the “Create Custom Drinks” screen to enter the amount of each ingredient for your drink. You can then pour the drink, or pour a “Taste Test” to try it and adjust ingredients if necessary.

The final screen is the “Priming/Cleaning” screen which allows you to control individual ingredients to clear air from the lines, backflow to empty the lines, or run a cleaner through.

Alan is continually updating the software and future features include drink pictures and the ability to save custom drinks. If you’re interested in the software you can contact me and I will pass your requests on to Alan.

Inside the Bar Monkey

ComputerThe software runs on a Windows PC which has been mounted in the Bar Monkey without a case. The PC controls a set of serial relays built from a kit. The kits can be purchased from

ValvesThe serial relay kit is used to control a series of 16 refrigerator water valves which run on 120 volt AC. These control the flow of each liquor to the tap. Since everything is live 120 volt Alan put together a Plexiglas shield to reduce the risk of electrocution.

C02 tankThe valves provide flow control but, just like in a refrigerator, something else needs to provide pressure. In Alan’s Bar Monkey the pressure comes from a five pound tank of CO2. The variable regulator on the tank regulates the pressure down to only 5 PSI and the valve coming off of the regulator provides easy shut off and converts the thread of the regulator to 1/4-inch outer diameter polyethylene tube. This tubing is the standard for hooking up water to a refrigerator and is available along with a wide variety of splitters, valves, and couplers at home improvement stores.

If you’re considering building your own Bar Monkey I suggest starting with the pressure system. Finding a size and style of tank that fits right and can be refilled locally, then matching it up with a regulator and converters proved to be quite a challenge. Pay special attention to the thread (right-hand or left-hand) of all connections to make sure it will go together in the end.

SplittersIn order to pressurize all 16 bottles the pressure line must be split. While I’m sure there is a more elegant way to handle this, we used T-splitters to make one end into two. It took quite a few splitters but they do not seem to leak. We also added valves to be able to shut off each side independently for easy refills. All the splitters and valves are a quick-connect type which allows the tubing to be removed easily to clean and reroute tubing.

capWe chose to use two liter soda bottles to hold all the liquors. Two liter bottles are surprisingly strong, cheap, common, and all have a standard cap. The bottles, caps and lines are all marked with painter’s tape to assure the right bottle goes on the right line.

capThe caps, which we thought would be easy, turned out to be the biggest challenge of the project. The caps, and the tubes which are glued into them, are made of polyethylene. The molecular bond of polyethylene is so strong it is almost impossible to glue. After several failed attempts with hot glue, cyanoacrylate, silicone and epoxy we finally landed on a solution.

This may sound a bit extreme, but in order to glue polyethylene you must “flash” it first… with a propane torch! By just touching the polyethylene with the blue inner flame of a torch it changes the molecular bond (this is a chemical change, not melting) in a way that it will take glue. We actually found this tip in an Old Town kayak repair manual.

The first step to making the caps was to drill two 1/4 inch holes in the cap. The plastic insert usually falls out at this point, but its absence doesn’t seem to hurt anything. You can then insert the tube through the cap. The tube going to the tap should be long enough to nearly reach the bottom, the other just needs to go through far enough to be solid.

Next we flashed the tubing and caps and wrapped a piece of painter’s tape around it to form a cup for the epoxy. At this point we put the cap on a half full bottle to keep it upright and poured enough epoxy to get a good thick layer. We used 30 minute epoxy but faster epoxy would probably work as well. Once the epoxy had a couple hours to set up the caps were ready to go.

The line which runs to the bottom of the bottle is run up to the valve array. Here wire ties and coaxial cable tack-downs were useful to keep things organized. As seen above, the valves were mounted on three boards to make them easier to install.

The tube coming out of each valve runs all the way to the output of the tap. That is why you can see separate colors on some of the pictures. The tap itself is half of a standard sink trap. Running all 16 tubes around the bend of the tap takes a little fidgeting but is possible.

The full monkeyThe housing of the Bar Monkey was an inexpensive computer cabinet from a popular box store. A hole was drilled in the top for the tap and plywood was used as a substitute for the cardboard backing that came with it. The handles were also replaced to dress it up a bit.

Final Thoughts

Alan, and those of us who helped him, learned a lot on this project. The whole thing took probably around 200 man hours to complete. We have not calculated the total cost, but if you were looking to build one of these yourself you should expect to be into it for up to $1,500 or possibly more depending on how much you can scrounge. I also wouldn’t recommend this as a project for anyone who is not comfortable working with household current.

project, diy, drinking, drinks, entertaining, bar, mixed drinks, bar monkey

RadioShack Screwdriver Sets – Great Tools for Small Work

National Weather Service LogoNeed a good $5-$10 gift for the tinkerer on your list? Buy them the last set of precision screwdrivers they’ll ever need!

RadioShack offers some fantastic precision tools, but only a few make it onto my must-have list. The Kronus 6-Piece Precision Phillips Screwdriver Set and corresponding slotted set are the exception. These are the type of tools you will wonder how you ever lived without.

The slotted set, RadioShack Model 64-2968 span from 1.0mm to 3.5mm in logical steps. Similarly, the Phillips, RadioShack Model 64-2969 ranges from 1.4mm to 3.8mm (the largest is roughly Phillips #1, but the others are too small for the normal Phillips measurement). Also, unlike some sets which come with a single handle and several interchangeable shafts, these are all fixed to the handle so there’s no more switching bits!

At $4.99 per set I highly recommend buying one of each, but if you take a look at the selection, RadioShack also has some combined sets with more or less tools.

Several years ago I purchased both these sets after being frustrated at not having the correct size of slotted driver while working on a turntable. Since then I have never been at a loss for the correct sized driver!

With free-spinning tops and great grips it is easy to apply the right amount of torque, and as for durability… well, I’m rough on tools and I don’t think I’ll be needing the limited lifetime warranty anytime soon.

While I’m sure I could get a comparable or possibly better set of precision drivers through one of the popular mail-order tool dealers but you just can’t beat simply walking into RadioShack and picking these up. You even save on shipping!

tool, tools, radioshack, building, electronics, repairs, diy, do it yourself, repair, modeling, models

MAKE Volume 2: More Good Stuff

Make: Vol 2In the gaps between teaching, work, bloging and working on some pet-projects I have finally finished MAKE: Technology On Your Time, Volume 2. Chock full of home entertainment projects, I am yet again impressed with the quality and quantity.

Highlights include HDTV on Your Mac, Atari 2600PC, and instructions on how to build a twitchy little robot out of a computer mouse. I’m glad the magazine only comes out quarterly… I could spend three months working on the projects from just one issue!

While the quality of the projects outlined in MAKE is undeniable, I am finding the true value of the magazine is how it has changed the way I look at things. I can only equate this to when I learned how to pick locks. Once you have picked a Masterlock and a few door locks your attitude toward locked doors changes. What was once a barrier is now a challenge, even one to look forward to.

MAKE has changed the way I view the world. A broken answering machine, old mouse, dead entertainment system, even a cheap Commadore64 direct-to-TV game have taken on a new value. I’ve always been a hacker, never afraid to take the screws out and rewire, but this is going to a whole new level!

More than a book full of projects, MAKE is full of new ways to apply technology, new tools, and true “maker” attitude. The value of MAKE, and it’s true spirit, is realized when you view it not as a bunch of projects and reviews, but as 200 pages of raw information just waiting to see how the reader will put it all together.

Will I build a Lego robot controlled by an audio chip? Podcast a lecture for a class I will be teaching? Perhaps build a desktop linear accelerator to annoy and harm my cube-mates! (just kidding)

Well, one thing is for sure… I’m glad my girlfriend got me a subscription for my birthday. Time to dig into Volume 3. I’m afraid I’ve only got a couple months until Volume 4 will arrive.

For more information on what started this new obsession of mine, check out this article about MAKE, and this retrospective on Volume 1.

make, oreilly, make magazine, hacks, hack, hacker, electronics, electronic, entertainment, technology, electric, home entertainment, diy, do it yourself,