Following on from Ha Ha Ha… 555 fun, after watching Dave’s video on the Three Fives kits by Mad Scientist, EEVblog #555 – 555 Timer Kit, I set about making a veroboard design. After a few hours I’d finally come up with a design that fits perfectly on 24T x 37H veroboard (see Veroboard).
The transistors 2N3904 and 2N3906 are £0.99 for 100 pieces of each:
- 100 Pcs 2N3904 Through Hole NPN Bipolar Transistors M5W5
- 2N3906 3 Terminals General Purpose PNP Transistors 100 Pcs R4O5
or for $0.99
- 100PCS TO-92 2N3906 General Propose PNP Transistor Top Quality
- 100 Pcs 2N3904 TO-92 NPN General Purpose Transistor NEW
Today I realised that I didn’t have any 555 timer ICs, which was a bit of an oversight, seeing as I need a couple for LFOs. So I ordered 100 for £2.40, 100PCS NE555P NE555 DIP-8 SINGLE BIPOLAR TIMERS IC factory price, what a bargain..! As I had over ordered, as usual, I thought that I had better find something to do with them…
Just for the hell of it, I wondered if it was possible to substitute the 555 timers in an Atari Punk Console (APC) with some other component, or components.
After seeing some Schmitt-trigger inverters (CD40106) used in oscillator circuits, see Swingers, I thought that I would come up with an alternative design.
A friend of mine sent me details of the 555 Noisemusick kit, which, while it looks like an Atari Punk Console (APC) – see Atari Punx… – it is essentially two astable multivibrators, with the first providing a CV input to the second, and with additional IR sensors and touch pads (rather than an astable followed by a monostable, which is what the APC is).
Following on from Atari Punx…, which was my first foray into the world of electronic sound generation, it seemed that a sequencer is a very useful piece of additional kit. One can be easily made using a CD4017 decade counter (or CD4022 octal counter)… However, other ICs can be used, to provide additional functionality. For example, a CD4510/CD4516 BCD/Binary counter and a decoder or 16 channel multiplexer, such as a CD4028 or CD4067, can add up/down sequencing, pre-loading and other features.
Let’s take a look at all of these ICs as well as some others.
VCO, VCF and VCA circuits are also touched upon, be are covered more fully in Banging noises…