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Battery Powered Behringer RD-6 Drum Machine

I’ve got a Behringer RD-6 Analog Drum Machine and it’s battery powered! I’ve seen a number of video reviews of this machine and the reviewer always seems to say “It’s not battery powered, so you can’t easily take it with you…” But I’m here to tell you that you can take it with you (just like Steve Albini did with his Roland TR-606) and below I’ll show you how.

Here’s what you need! A Behringer RD-6 Analog Drum Machine. Any color will do. Mine is red.

A battery pack that will hold 6 AA batteries. Each battery is 1.5 volts, so 6 of them is 9 volts. (And no, a standard 9 volt battery won’t work due to the low amperage it can put out.) I had some lying around that were like this but some have connectors on them like these. As long as they have bare wires at the end, you’re good. If they do have a connector on the end you may need to chop it off. (More on that later.)

You’ll need a 2.1mm Barrel Power Jack. I usually buy a pack of them. You only need one, so find one, or buy one, or buy a bunch and have spares. (You won’t need the matching receptacle plugs. At least not for this project.)

Important! All of the barrel jacks I’ve purchased have positive in the center and negative on the outside of the barrel. In the world of musical things (well, guitar pedals at least) negative is on the center, and positive is on the outside of the barrel.

Here’s the back of the RD-6. You can see the symbol showing negative in the center. Note that it also shows 300 milliamps. A 9 volt battery is 500 milliamps, so it will work for a while, but not long. The power supply Behringer gives you is 670 milliamps, but it’s not a battery, it plugs into a wall socket.

Right so we need to… reverse the polarity! Luckily it’s as simple as switching the wires around. Normally red is positive and black is negative, but we’re switching those. Make red negative and black positive.

Here’s mine. Now, it’s worth noting that I checked all of this with a multimeter. I’d advise you to do the same. Double check your work. If you don’t know what you’re doing, ask someone for help. This probably voids your warranty, and I cannot be held responsible for what you do. On with the show!

Oh, you’ll also need batteries! Any AA batteries will do, but rechargeable are preferred, at least by me. I’m a fan of the Eneloop rechargeable batteries. I’ve got some I bought ten years ago that still work. Grab a charger and 4 batteries and, um… 4 more because you need a total of 6 batteries.

Okay, stick it all together and you get a battery powered drum machine. Boom. Tsk. Boom. Tsk. I haven’t testing how long a set of batteries will last, but I’ll add that to the list of things to do.

Now, it’s not as nice as internal batteries that are built into the case, and if I actually use this on a regular basis I might think about adding in some hook & loop to attach the battery pack to the side. It might be better to use two 3 AA battery packs wires together, since those would have a flat back that could be attached to the RD-6.

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Cardboard Knife Switch

For many electronics enthusiasts there is a special place in their heart for knife switches. At least that’s the case for educators I’ve worked with the past decade or so. My guess is it has to do with the simplicity of the knife switch in explaining how a circuit works. Is the circuit opened or is it closed? A knife switch provides a visual demonstration of this like few other switches do nowadays.

Knife switches are not used for most modern day circuits as they have been replaced by switches that are safer at high voltages, but since we work with low voltage circuits in educational settings this DIY Cardboard Knife Switch is perfect.

I’ve talked to a few educators and heard complaints about how expensive the old style knife switches are. (You can buy new “cheap” plastic versions for about $2 per switch, but the ceramic ones are often $10 or more.) I thought I’d lower the curve by creating a cheap DIY version that can be made with Maker Tape.

There’s a template that can be used to make one from cardboard or other material that’s got some rigidity and thickness to it. Cardboard is great, foamcore could work, cereal boxes are too thin. The template expects some cardboard and a way to cut it, which could be an X-ACTO knife, some scissors, a razor blade, or even a laser cutter.

Once you have your four pieces you attach some conductive Maker Tape, poke some holes for the brass fasteners to go through, and you’re nearly done!

Assemble the four pieces using the brass fasteners to hold them together and to act as a pivot point for the lever and you’ve got a knife switch. It may help to pinch the top of the two outside pieces a bit narrower so the knife is guided into place a bit better. (You’ll see this tip and more in the PDF guide.)

Besides the Brown Dog Gadgets Project Database, you can also find this project on Instructables.

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Seeeduino Nano

The folks over at Seeed Studio sent me a Seeeduino Nano to check out. I’ve used a lot of Arduino boards over the years, including plenty of cheap Arduino Nano clones. Most of the clones have worked fine but every now and then I’ve seen a bad one come through. The Seeeduino Nano is a nice quality board with a little extra to make it useful for beginners or people more interested in making things quickly/easily than they are soldering wires.

One interesting thing about the Seeeduino Nano is that it used USB-C to connect to your computer. While most of the Arduino UNO boards I’ve used still use USB type B, and lots of other boards use Mini-USB or Micro-USB, the Seeeduino required a USB-C cable. Luckily, I had one on hand. If you don’t already have a USB-C cable, you’ll need one for the Seeeduino Nano.

My favorite part about the packaging of the Seeeduino Nano is the warning on the back that says “Best to keep away from fire”, mainly because I’ve worked on multiple Arduino projects that specifically involved fire… But I digress… for most people keeping away from fire is probably a good idea.

Here’s the top view of the Seeeduino Nano next to a ELEGOO Nano board. You can see the difference in the USB connector and a few other features. One difference with the ELEGOO boards is that they come with the header pins included but not soldered in place. (Here I’ve soldered them to the board.) There are times when you don’t want header pins solder into place. My guess is that for the target market of the Seeeduino Nano, the pins already installed makes sense.

Another thing about the ELEGOO boards is that I can’t easily find them listed on the web site. Here’s a post about them, but in the past if I’ve purchased them I’ve found them on Amazon for a price close to the Seeeduino Nano, though I’ve only seen them as a 3-pack.

(Note in the photo above the boards are the same dimensions, the Seeeduino is just on an angle due to the extra connectors on the top.)

Since I had a project already done with a Nano in place (via my Anrduino Nano Breakout Board) I just swapped in the Seeeduino Nano, uploaded the code, and it worked great.

Where the Seeeduino Nano really shines is the capabilities it has with the Grove system from Seeed Studios. If you don’t want to solder, and also don’t want to stick a lot of wires and components into breadboards, the Grove system might be what you are looking for. Again, I see this is a match for those who are more interested in the code than the wiring of electronics, or for workshops where soldering might be a concern (with kids or those not able to solder for other reasons).

In the photo above you’ll see the Seeeduino Nano along with the Grove Shield, a Temperature & Humidity Sensor, and a connector wire.

It’s also worth noting that the Seeeduino hardware and Grove system are open source, and others have embraced Grove. Adafruit has a Grove Shield for Particle Mesh and Feather Boards.

Above you’ll see the Seeeduino Nano plugged into the Grove Shield which has a Temperature & Humidity sensor attached. This takes seconds to connect versus soldering things or plugging things into a breadboard. When I taught basic Arduino classes I always told students to unplug their Arduino when they wired up the breadboard, and then to double-check the wiring for errors before plugging in the board again. The Grove plug-in system eliminates much of that guesswork. You can’t really plug things in backwards.

Here’s the Temperature & Humidity Sensor. I’ve worked with logging temperature and humidity before, so I’m not really new to this. The new part is the simplicity of just plugging things in.

I grabbed the example code Seeed Studio provided and had a few issues. Nothing I couldn’t fix, and I did open an issue about it. In the end I grabbed Adafruit’s library for the DHT Sensor as well as the Adafruit Sensor library (which is required by the DHT library) and got things up and running. If you’re not interested in downloading zip files from Github you can also install these libraries right from the Arduino IDE.

Overall the Seeeduino Nano is a good quality Arduino board, and the Grove system makes it very easy to get up and running. In this specific test I did run into some trouble with their example code, but in most cases those issues are solvable, and there’s probably an alternative example or library out there that will do what you want or need.

Finally, here’s a short video of the game scoring system I mentioned above. The Seeeduino Nano is taking input from a number of pins (that will eventually be triggered by switches or buttons) to keep score, where each pin is a different point value, and then using the piezo speaker to play a sound for each point value as well as displaying the points on a small LED display.

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Rapid On/Off Time (Almost)

timer-2703

I should have known this project was doomed from the start. When I laser cut a piece of paper to test the fit of the components, I somehow managed to flip around the holes for the LED displays, so I ended up building it flipped from what I designed. If that was the only issue, things might have been okay…

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Hey, things fit! This was all good (though as mentioned, flipped) and as a front panel it looks fine. Let’s move on to the back of things…

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Still good! A few laser cut spacers to get the LED panels flush. The rotary encoders and the outlet are all good. Of course we still need to add wires to get it all connected.

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Wires in place. Not bad. I added an Arduino Nano with one of my breakout boards and screw terminals, and there’s a relay module to be controlled by the Arduino. All good.

The idea was that the first encoder would control how many seconds/minutes the outlet was on and receiving power, while the second encoder would control how long the outlet was off or not receiving power. This would allow me to control a 120 VAC device turning it on and off for set amounts of time. (I know, I probably could have used a timer relay, but I wanted to build something.)

Somehow, I never quite got the code to work. Maybe there were some weird issues with the encoder library, or using two encoders, along with the LED panels, I don’t know… but I tried for a few hours to get it to do what I wanted, and it never did. Typically with code issues I bang at it until it works, but for this I just sort of gave up.

In the end it didn’t matter much because I ended up using a variac to lower the voltage instead of togging the full 120 VAC on and off. I also ended up stealing the LED panels and the Nano for another project that had to be done in a hurry. I’ve still got the other parts in place, so who knows? Maybe I’ll return to it in the future…

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My First Noisemaker

Noisemaker from the 1980s4938

I came across a treasure in one of the (many) boxes of “old things” in the basement. What you see is a Radio Shack project box with a speaker and a switch on it. Yeah, it’s a noisemaker, and I built it in the mid-1980s.

Fun fact, I used to do electronics in high school, and while I’m not sure this was a project we did in class, I’m guessing I may have built it around the time I was in school. It was probably around 1985 or so, if I had to guess. (I think I took two years of electronics classes.)

Noisemaker from the 1980s4939

The speaker has a “grill” that appears to be made from a metal screen, maybe from an old scrap window screen? I do know it would have been built with whatever stuff was around the house. I think I used Elmer’s glue to attach the screen to the speaker. It seems to have held up! The lettering for the “ON” label was most likely done using Liquid Paper and there’s a bit of clear Scotch Tape covering it as a protective layer. This also held up well!

Noisemaker from the 1980s4940

There’s a hole in the case. I’m not sure why. If I had to guess, I probably burned it with my soldering iron. I should say “Solder Gun” because at home we had one of these, and I don’t know if it belonged to my dad and I used it, or he bought it for me, but I do remember it wasn’t easy to solder with. At the time I didn’t realize this wasn’t the preferred tool for delicate electronics work…

Noisemaker from the 1980s4942

It looks like the soldering joints on the speaker held up fine… not so much for the masking tape, which dried up and lost its “stick”. I guess I just taped the speaker down, and used the tape as an insulator for the speaker contacts. (I did not know about hot glue yet.)

Noisemaker from the 1980s4945

Let’s pop this sucker open! Solid core wire and a 9 volt battery connector are visible. There’s also a piece of paper that I assumed was to insulate the metal battery housing from the electronics. And then…

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I took out the piece of paper and… oh my gawd, I actually documented this thing. There’s a circuit diagram and a Bill of Materials! This explains so much about my life, and honestly, I’m sort of proud of teenage me. Good Job, Petey!

And no, it’s not a proper schematic, but it’s approximately how I document most of my work/projects nowadays, using circuit diagrams, like you might create with Fritzing.

Noisemaker from the 1980s4947

Finally! We’ve got a perf board inside with a few components soldered onto it, and rudimentary strain relief by running the wires through the mounting holes of the perf board. Well done, Petey!

Noisemaker from the 1980s4949

Let’s flip it over and… oh my gawd, the soldering! Sheesh! Now I am embarrassed! But this does lead me to believe I did this project at home, since that’s where I was using a giant soldering gun and giant solder not quite suitable for delicate electronics. Oh well, at least my soldering skills have improved since the late-1980s!

Oh, in case you’re wondering how it works, look at the diagram for a clue. You touched the metal bolt sticking through the enclosure and the top metal piece of the enclosure, and you completed the circuit, and could get weird tones based on how much you touched and how hard you pressed. I was really hoping to include a video but sadly, it did not work after 30 years of sitting in a box. Drat!

(And yes, I’m really tempted to build a new version of this to see what it sounds like!)