Hello,
During the summer holidays I will be working at a summer camp in PA, USA teaching simple electronics to children between the ages of 7 and 15. I have been asked to come prepared with a selection of different circuit that I could teach the children and that they could build.
In search of circuits I came across Forrest M. Mims series of Engineer's Mini Notebooks and decided to buy them. I have to say they are an interesting read so far and there seems to be lots of fairly simple circuits that would be suitable to teach to children.
The "Toy Organ" on page 23 of Volume I struck me as a fun circuit to teach the children, without requiring too much theory. For those of you without access to this book I have copied the circuit onto the computer:
So my questions are... it surely must be possible to instead of using capacitors that seem to be in the E6 range use resistors? If my understanding is correct (I'm scratching my head here, because we're going back a number of years since I studied this sort of stuff) the 555 timer uses an RC setup to provide it's time base? Therefore, a range of resistors could be used and a fixed capacitor value instead?
Also thinking about fabrication, using tactile switches would be an expensive solution. Therefore it got me thinking about touch sensitive switches. Correct me if I'm wrong... but a Darlington pair could be used to create a touch switch, which would operate when you touch your fingers on two PCB pads?
The circuit suggests 15 capacitor values, but you could just as easily use more or less. From memory I believe a Darlington driver IC package is available in both 7 and 8 pair versions? Using two would give you 14 buttons and in effect two octaves?
This website looked quite useful because it gives the different frequencies of notes on instruments. As can be seen, the toy organ more than covers a lot of the range. The human ear can only hear 20Hz to 20kHz I believe, so the range isn't a problem.
I believe that touching more than one switch at once would give interesting results... but this isn't a problem, I'm not looking for a polyphonic solution or anything fancy. Just a fun circuit to teach kids, whilst explaining the theory behind it.
Looking forward to hearing from people, if there is anything else that I can provide let me know and I will do my best
During the summer holidays I will be working at a summer camp in PA, USA teaching simple electronics to children between the ages of 7 and 15. I have been asked to come prepared with a selection of different circuit that I could teach the children and that they could build.
In search of circuits I came across Forrest M. Mims series of Engineer's Mini Notebooks and decided to buy them. I have to say they are an interesting read so far and there seems to be lots of fairly simple circuits that would be suitable to teach to children.
The "Toy Organ" on page 23 of Volume I struck me as a fun circuit to teach the children, without requiring too much theory. For those of you without access to this book I have copied the circuit onto the computer:
So my questions are... it surely must be possible to instead of using capacitors that seem to be in the E6 range use resistors? If my understanding is correct (I'm scratching my head here, because we're going back a number of years since I studied this sort of stuff) the 555 timer uses an RC setup to provide it's time base? Therefore, a range of resistors could be used and a fixed capacitor value instead?
Also thinking about fabrication, using tactile switches would be an expensive solution. Therefore it got me thinking about touch sensitive switches. Correct me if I'm wrong... but a Darlington pair could be used to create a touch switch, which would operate when you touch your fingers on two PCB pads?
The circuit suggests 15 capacitor values, but you could just as easily use more or less. From memory I believe a Darlington driver IC package is available in both 7 and 8 pair versions? Using two would give you 14 buttons and in effect two octaves?
This website looked quite useful because it gives the different frequencies of notes on instruments. As can be seen, the toy organ more than covers a lot of the range. The human ear can only hear 20Hz to 20kHz I believe, so the range isn't a problem.
I believe that touching more than one switch at once would give interesting results... but this isn't a problem, I'm not looking for a polyphonic solution or anything fancy. Just a fun circuit to teach kids, whilst explaining the theory behind it.
Looking forward to hearing from people, if there is anything else that I can provide let me know and I will do my best
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