The Bleep Kit!
There’s nothing like a simple, easy-to-use, portable noise maker! In Burnkit2600′s arsenal there are several little sound FX circuits capable of the perfect siren, crash or even simple little solo synth sound at the touch of a finger.
We decided to take one of these circuits and make it available in a kit that’s perfect for beginners and flexible enough for advanced experimenters.
The result is The Bleep Kit!
Requiring no soldering, the kit gives you the ability to experiment with basic sound circuit and instrument design.
The Bleep Kit is based on the CD40106 Hex Inverter Schmitt Trigger circuitry capable of producing 6 square waves that are combined at an amp circuit to create a complex sound.
You’ll assemble the circuit with the provided parts on a small breadboard. There are enough parts to build 6 square-wave oscillators using capacitors and variable resistors. You’ll experiment with the frequency ranges of different parts combinations. You’ll try out different control methods like switches, pots or light-reactive photocells. You’ll make all manner of sounds: alarms, beeps, tones, wails, whales, arpeggios and i don’t knows.
Experiment with different combinations of parts and control types until you find something you love. Mount the controls in a permanent fashion or leave the circuit open to further experimentation and expansion – The choice is yours!
BUY IT NOW!
$55 via our Bandcamp site.
Let’s start by learning about the kit contents!
These are used to experiment with building circuits.
The breadboard has points that are internally connected below the surface. This allows us to connect components together without soldering them.
This is the LM386 chip. It’s a low voltage, high powered audio amplifier.
It’s a widely used chip in all sorts of popular D.I.Y. projects and commercial equipment like radios, guitar amps, TVs and has been for decades!
This CMOS chip has 6 high speed inverters built into it. Pairs of legs on the chip are inputs and outputs. Voltage presented at the input becomes inverted at the output. So when the input voltage is high, the output is low, and when the input is low, the output is high. We’ll be sending this output back to the input, creating controllable feedback loops. These loops are our square wave oscillators!
Insulated Jumper wires. The lengths of wire included in the kit. Use this to make direct connections between otherwise unconnected points on the breadboard. It’s a great conductor of electricity, and electrons flow across it unhindered.
Resistors. ‘Fixed’ and ‘variable’ resistors shunt the flow of electricity at given values whose basic unit is called an ohm. For our purpose, resistance will be added to the circuit to change the frequency of the oscillators we are building.
Fixed 100K carbon film resistors. Carbon is a good conductor of electricity. The carefully controlled amount of carbon in the resistor increases its ability to conduct electrons. The color code painted on these describes the resistance of the part as being 100,000 ohms. We will call these 100K Resistors. It is a fixed resistor in that you can not alter the resistance value of that part.
Variable resistors have adjustable amounts of resistance. Variable resistance will allow us to tweak the frequency of the oscillators. We have 2 kinds of variable resistors in the Bleep Kit.
Potentiometers, or pots for short, have a tweakable resistance amount. Turn the pot, add more resistance.
There are 2 pots in the Rev 2 Bleep Kit. Their available resistance in ohms is 500K and 200K. These parts generally have their resistance value printed in text on them some where. There are 2 wire leads that have been pre-soldered to your pots that can be plugged into your breadboard.
The other variable resistors in the Bleep Kit are Light Dependent Resistors (LDRs for short). We’ll be calling them Photocells. They have a vein of cadmium sulphide painted on their face. This material’s conductivity changes in the presence of light. So, when light hits the face of the photocell, the resistance amount changes. The Bleep Kit includes several photocells with different amounts of cadmium sulphide on them and therefore different resistance values.
Capacitors or caps for short, are like little rechargeable batteries. They store up electrical charge and when they are full, they discharge their contents and begin again. The amount of charge a capacitor can hold and the rate at which they are discharged are expressed by the markings printed on them. This print can be as little as a 3 number code, or have the amounts written out in their entirety on them.
One of the capacitors in the Kit requires a bit of attention.
The 100uF electrolytic capacitor (pictured at far left) is polarized. That means it has a negative and positive pole and they need to be oriented in the right direction. Care should be taken to ensure that the clearly marked negative pole of the cap is properly identified.
LEDs or Light Emitting Diodes are semiconductors that light up in bright colors. They are diodes which means that electrons can only move across them in one direction – Up the long legged side (annode) and down the short legged side (the cathode). The cathode side also has a flat indentation on the LED body used for orienting the part correctly. If too much voltage is applied to the LED it could burn out.
There are lead wires soldered to the posts on the backs of them and when engaged, a physical connection is made between these leads. The pushbutton makes a momentary connection between the leads when engaged. The toggle switch latches and remains engaged until clicked off.
OK! Prepare yourself to build an analog synthesizer!
The Bleep Kit synthesizer consists of an array of oscillators and controls, as well as an amplifier and speaker to make the sound audible.
If you’ve got a spare half hour, watch this tutorial video.
Text descriptions follow.
Let’s get started with the basics.
First we need to understand the breadboard! Take a look at this diagram-
Check out your breadboard, orient it like it is above. Note that there are numbered columns and lettered rows. When we describe individual points on the board we will be using a system of coordinates like in the game of Battleship – where a pin falls in a specific spot marked by a number and a letter.
The light grey lines in the diagram above show how the points are connected underneath the plastic within a conductive layer of the breadboard. The points in each numbered column are connected to each other up to the split that runs the length of the board. For example, point 1A is connected to 1B, 1C, 1D and 1E only; 1A is not connected to 1F or 2A. 1F is connected to 1G, 1H, 1I and 1J, but not 1E, 2F or 2A.
On the edges of the board are 4 Positive (+) Power Rails and Negative (-) Ground Rails. We will describe these rail sets as upper and lower rails. As the grey lines show in the diagram, the points on these rail rows are connected internally. They provide an easy way to provide multiple power and ground connections that circuits require.
Now that that’s out of the way, Let’s begin!
We will need to connect together the 2 Negative (-) Ground Rails.
1) Connect a jumper wire from the UPPER Negative (-) Ground Rails to the LOWER Negative (-) Ground Rails. It’s best to do this on the far left.
The amplifier is an LM386 chip. It has 8 legs, or pins. There is a dot engraved on top, just above a pin. That’s pin #1, and it should be placed on the breadboard at 27E. Pin #8 is opposite pin #1 and should be in 27F.
The installed speaker has two leads coming off of it.
2) Connect the Speaker’s Negative Lead (black wire) to the upper Negative (-) Ground Rail.
3) Connect the Speaker’s Positive Lead (red wire) to the amplifier output in point 26J.
The amplifier needs power.
4) Connect a short wire jumper, from the upper Positive (+) Power Rail to point 29J.
5) Connect a jumper wire from the lower Negative (-) Ground Rail to point 28A.
6) Connect a jumper wire from the lower Negative (-) Ground Rail to point 30C.
There are 2 capacitors to connect in the amplifier stage. The first is the electrolytic bipolar cap – It’s a blue cylinder with white markings describing it as a 100uf cap. It’s the only cap that is polarized, meaning that it has a positive lead and a negative lead. Note the white markings denoting the negative lead on the capacitor, which is also slightly shorter than the positive lead.
7) Connect the negative lead (shorter wire) of the 100uf capacitor to point 30I.
8) Connect the positive lead, (longer leg) in to point 26I.
The next cap sets the amplifier’s gain (volume level). We chose a 103 cap (.01uf), this is marked with some printed text including the number 103.
9) Connect the 103 capacitor leads to points 27D and 27G. This cap should now be straddling the amp chip.
Lastly, we’ll need to connect the amplifier input wire.
10) Connect a jumper wire from points 29C to 16C.
That’s it for the amplifier section, your breadboard should now look like this:
Let’s work on the oscillator.
The CD40106 Hex Inverter Schmitt Trigger! – We’ll use this to create our oscillator bank!
The chip has 14-pins. The chip should be oriented like it is in the pictures above. It’s pin #1 (lower left pin) should be in 1E of the breadboard and it’s pin #14 should be in 1F.
Use jumper wires to provide power to this chip from the 2 sets of power rails.
11) Connect a jumper wire from point 7A to the lower negative (-) power rail just below 7A.
12) Connect a jumper wire from point 1J to the upper Positive (+) Power Rail.
Let’s build our first oscillator.
Find a 104 capacitor. It’s a little blue cap with “104″ printed on it.
13) Connect the 104 capacitor in points 1A and the lower Negative (-) Ground Rail.
14) Connect the leads of a 100K resistor in points 1D and 2D.
This combination of a capacitor and resistor together create a feedback loop and thus create an oscillator.
Now we’ll need to connect the oscillator output to the amplifier.
15) Connect a jumper wire from points 2C to 14C.
Next we’ll put an LED in line with the output to get visual feedback as well as sound!
Grab a green LED and take a look at it. It’s got a long leg and a short leg relating to the anode and cathode. The short legged cathode side of the LED is also recognized by a flat impression in the LED body itself just above where the lead meets the body.
16) Connect the LED’s long lead to point 14E and the short lead to point 16E.
Your completed oscillator and amplifier should look something like this:
Now let’s hook up power!
17) Snap your 9V battery into the 9V battery connector.
Now the 9V battery connector leads need to be hooked up.
18) Connect the battery’s RED LEAD (+) to the upper Positive (+) Power Rail.
19) Connect the battery’s BLACK LEAD (-) to the upper Negative (-) Ground Rail.
At this point, you should be getting sound and your LED should be lit!
If not, stop here and double check all your connections.
Your 2 Ground (-) Rails, upper and lower, should already be connected with a jumper wire. Pay special attention to all your leads and the orientation of your LED, and the electrolytic capacitor on the amp.
If it’s working, Great let’s experiment with some more of the kit’s parts!
You can stop your tone by disconnecting the battery’s BLACK LEAD from the upper Negative (-) Ground Rail.
We can make it easier to turn the circuit on and off by adding a switch in between these points.
The Pushbutton Switch mounted in the case has 2 interchangeable leads soldered to it.
When the button is pushed, a connection is made mechanically in the switch between the 2 leads.
20) Connect one of the Pushbutton lead wires to the upper Negative (-) Ground Rail
21) Connect the other Pushbutton lead to point 22I.
22) Connect the battery’s BLACK LEAD to point 22J.
Now push your button! This should complete the ground connection and turn the circuit on.
The sound is a little boring though- just a buzz like in the game Operation or like you answered a question wrong on a quiz show.
Let’s add some variation to the sound!
Our oscillator’s FIXED 100K resistor is setting the frequency of the tone. Let’s swap the resistor out for a VARIABLE resistor.
The 500k potentiometer mounted in the case next to your breadboard has 2 interchangeable lead wires running from it.
23) Remove the 100K resistor from points 1D and 2D.
24) Connect the leads of the 500K pot to points 1D and 2D.
Now press the button and turn the pot’s knob. You’re sweeping the amount of resistance and thus the frequency of the tone.
Let’s experiment with the potentiometer mounted in the other half of the case – it should be 200K or 250K. That’s half of the first pot. You will hear the difference in resistance amounts and feel the difference in the pot sweep as you turn it.
25) Remove the leads of the 500K pot from points 1D and 2D.
26) Connect the leads of the 200K pot to points 1D and 2D.
You should be able to detect the differences between the 2 pots pretty easily.
Now lets experiment with the kit’s photo-sensitive photocells by putting them in place of these pot leads.
Start with the smallest photocell in your kit.
27) Remove the leads of the 200K pot from points 1D and 2D.
28) Connect the leads of a photocell to points 1D and 2D.
Now press the button and wave your hand over the photocell, blocking light going to it.
The more light that hits the top of the photocells, the higher the pitch goes.
Block the amount of light getting to it with your hand, or add more light with a flash light.
You’re playing a basic photo-theremin!
Try each of you photocells in place of the current one and notice the different ranges each has in full light and darkness.
Some photocells may not have a noticeable effect in this arrangement.
Oscillator experimentation with a potentiometer is a bit easier to control, so let’s put that 500k pot back in place for now.
29) Remove whatever photocell you’ve got in points 1D and 2D.
30) Reconnect the leads of the 500K pot to points 1D and 2D.
Now you’ve got a decent idea of what all your different variable resistors are capable of in an oscillator.
But the capacitor in the oscillator effects the sound as well.
Now let’s try swapping in different capacitors with different values.
31) Remove the 104 capacitor from points 1A and the lower Negative (-) Ground Rail.
32) Connect a 103 capacitor in points 1A and the lower Negative (-) Ground Rail.
Play with the arrangement and notice how the different caps in your kit give you different frequency ranges.
Let’s replace the 104 cap and move on!
33) Remove whatever capacitor you have in points 1A and the lower Negative (-) Ground Rail.
34) Reconnect a 104 capacitor (0.1 uF) in points 1A and the lower Negative (-) Ground Rail.
Adding additional oscillators will make the sound more complex and interesting to listen to.
So let’s build a second one!
Let’s build a second oscillator!
The construction of the any additional oscillator we’ll be very similar to what we’ve just created with the first one. A capacitor and resistor combine to make a feedback loop with a frequency we’ll rev up to audio range. The only real difference is where to begin, and in this case it’s with pins 4 and 5 of the CD40106 – so get your parts ready!
Obtain a 105 capacitor (1uF), a photocell, a jumper wire and a green LED.
35) Connect a 105 capacitor (1uF) in points 3A and the lower Negative (-) Ground Rail.
36) Connect the leads of a photocell to points 3C and 4C.
37) Connect a jumper wire from points 4D to 12D.
38) Connect the Green LED’s long lead to point 12E and the short lead to point 16D.
So now you have 2 oscillators set up! Try it out. You may need to try different photocells out to see which works well with this set up. You should be able to use the controls for both oscillators – the pot on the right and the photocell to make some unique new tones. The square wave outputs combine together at the amplifier input to make this more complex sound. Take a moment to familiarize yourself with this sound and then we’ll move on!
Now try swapping in a different capacitor into the first oscillator to hear the difference.
39) Remove the 104 capacitor (0.1 uF) from points 1A and the lower Negative (-) Ground Rail.
40) Connect a 105 capacitor (1 uF) in points 1A and the lower Negative (-) Ground Rail.
Do you hear how swapping these 2 caps changes the range in your sound? What does swapping out the 2nd oscillator’s capacitor in 3A do for your sound?
Replace those first 2 caps if you’ve swapped them out so you’re where we were in the last step, that is – both oscillators should have a 105 capacitor.
Before we move on, let’s gain some more control of this 2nd oscillator. Swap the photocell in oscillator 2 for the leads of the 200K-250K potentiometer in the other half of the case.
41) Remove the leads of the photocell from points 3C and 4C.
42) Connect the leads of the 200K pot to points 3C and 4C.
With this set up, you’ll be able to dial in more exacting oscillator frequencies and really get a feel for what what oscillator is doing within the square wave mix. Tweak them both to their limits and check out what happens when they are turned near the top of their range. Frequencies begin to fold on themselves -Weird stuff.
So Let’s go for the third oscillator!
Construction should be coming easier for you by now. Select a 104 capacitor (.01 uF), a photocell, a jumper wire and a Red LED.
43) Connect a 104 capacitor (0.1 uF) in points 5A and the lower Negative (-) Ground Rail.
44) Connect the leads of a photocell to points 5C and 6C.
45) Connect a jumper wire from points 6D to 13B.
46) Connect the Red LED’s long lead to point 13A and the short lead to point 16A.
Check out the complex combination of square waves that 3 oscillators will create! And the combination of using the 2 pots with the right photocell can be very expressive. To gain a better understanding of what’s happening with the 3rd oscillator, let’s change it’s capacitor to hear the difference.
47) Remove the 104 capacitor (0.1 uF) from points 5A and the lower Negative (-) Ground Rail.
48) Connect a 103 capacitor (.01 uF) in points 5A and the lower Negative (-) Ground Rail.
To make this easier to experiment with, let’s get our toggle switch parallel with the pushbutton switch. The switch mounted in the 2nd half of the case has 2 interchangeable lead wires coming off of it.
49) Connect one toggle switch lead to 22H.
50) Connect the other toggle switch lead to the Upper Ground Rail.
Now you can either momentarily turn on the circuit with the pushbutton, or latch the sound on with this toggle switch to free your hands up to fiddle with the knobs and photocell.
Let’s Get Experimental
If you’ve been following along thus far, then you’ve got 3 oscillators mixed with LEDs all oriented in the ‘correct’ orientation – with the short legged, flat, cathode side pointed to the right toward the amplifier chip. However, when more than one oscillator is in use, we can mix them together in some unusual ways. Let’s try flipping some LEDs around.
Latch your circuit ‘on‘ with the toggle switch so you’ll hear the difference in the sound.
51) Flip around the 3rd oscillator’s Red LED so the short lead is in point 13A and the long lead is in point 16A.
52) Flip around the 2nd oscillator’s Green LED so the short lead is in point 12E and the long lead is in point 16D.
You should have noticed some slight differences in the enveloping or tone of your beeps. Experimenting with LED orientation is a good way to find some different sounds, and depending on your overall circuit setup, it may have a more or less pronounced effect.
The oscillators can also be used to modulate or shape the sound, or even create little sequences.
Pin 7 of the amplifier chip is a bypass pin. Voltage and capacitance on this pin augments the gain stage of the amplifier. We can use this to our advantage!
51) Move the 3rd oscillator’s Red LED so the short lead is in point 13A and the long lead is in point 19A.
52) Connect a Jumper Wire to points 19B and 28H.
You should notice the pitch of your tone modulating in a new way as you change the amount of light entering the 3rd oscillator’s photocell. Let’s put a more consistent form of resistance here in the third oscillator to experiment more with this feature. We’ll swap the photocell for a series of fixed resistors. So get 2 of your 100K fixed resistors ready.
53) Remove the leads of the photocell from points 5C and 6C.
54) Connect a 100K fixed resistor to points 5D and 10D.
55) Connect a 100K fixed resistor to points 10A and 6C.
The two 100K resistors are added in series to create 200K (200,000 ohms or 2 kilo ohms) worth of resistance in the 3rd oscillator. With this in place, you’ll be able to discern more readily what the amp bypass is doing to our sound now. Tweak the knobs to hear the sound goes from a sequence of pitched beeps to a complex squelchy sound.
Let’s go deeper and set up a 4th oscillator!
We’ll be moving to the other side of our CD40106 chip. Setting up oscillators on this side is basically the same, except that now we are moving in the opposite direction. Locate a 105 capacitor (1uF), a photocell, an amber LED, and 2 jumper wires.
56) Connect a 105 capacitor (1uF) in points 7J and the UPPER Negative (-) Ground Rail.
57) Connect the leads of a photocell to points 6H and 7i.
58) Connect a jumper wire from points 6Gto 15G.
59) Connect the Amber LED’s long lead to point 15J and the short lead to point 18i.
60) Connect a jumper wire from points 18F to 29B.
Try replacing those 2 fixed resistors in oscillator 3 for another photocell. You should have some unusual results! Another thing to try is swapping LEDs for other colored ones. Each LED has a different power requirement to light it, and thus passes through different amounts of voltage. So, different colored LEDs will change the character of your sound in subtle ways.
I think that’s as far as I’ll need to take you on this text-based experimenter journey. Based on what you’ve learned you should be able to build out 2 more oscillators. Simply model what you’ve done with oscillator 4.
Oscillator 5 would use pins 10 and 11 of CD40106. So, apply a capacitor from a point along 10 to Ground. Put a resistor across points on 4 and 5. Use a jumper and an LED to send oscillator 5′s output over to the amp input.
The same goes for creating oscillator 6; except now we’re using pins 12 and 13 of CD40106.
Of course the more oscillators you have, the more complex the waveform is, and possibly harder to control. So, continue to experiment with methods we’ve tried earlier.
Of course, you could have stopped anywhere along with our progress. That is, there’s no need to build out all 6 oscillators if you like the sound your getting with 1 or 2. If you want to start from scratch, remember to always start with pins 1 and 2 on CD40106 for your first oscillator and work your way around the chip like we have here for the best results.
Don’ t be afraid to try different combinations of oscillator styles and controls. Try to use the button in a new way – maybe to turn on just one oscillator?
Here’s a couple more random tips: If you’ve got a spare LED when you’re done, you could put it line with the speaker. Connect the long leg to the speaker’s positive line and Ground the short leg. It’ll blink when there’s sound.
You can change the volume of the sound by swapping in different capacitors in the gain stage. Swap that 103 cap out for larger and smaller ones and hear the difference.
Anyway, I think that covers all of the basics! This text followed more or less what was done in the Bleep Kit Tutorial video.
If you’ve made it this far, then you’ve unlocked access to the bonus expert mode.
Experiment with your parts and see what you can build.
In the comments section below, I’ll post some of my favorite ‘patches’ as I find them.
Try them out, and feel free to share your favorites as well!