Electronics > Projects, Designs, and Technical Stuff
Playable electronic modules - modules in action
<< < (9/16) > >>
nctnico:
Why not make one large board with IC sockets and header connectors for each pin? This saves a lot of tedious soldering.
Decades ago I made this:

This has been great for learning logic circuits. It has a 5V power supply, LEDs, switches, transistors, two oscillators and some sockets to put discrete parts in. One thing I'd do differently is to have two or three headers per pin so I don't need daisy chain wires. This board was hand drawn using a velt pen BTW. I had to cut it into two pieces because the entire board wouldn't fit in my etch bath.
HendriXML:
I really like the idea of just exposing a socket, and make multi purpose modules. Not having to solder on the bottom side would save a lot of time too.

But for this educational beginners project I started with a very narow focus on just connecting Outs and Ins. As skills progress it may get more complicated in usage. For example finding out what pins do what on a IC.

For children it requires different properties than just beeing functional. Smaller modules are probably more “playable”. I’m no expert here, but I’m exploring the possibilities hoping the choices I make will turn out ok. (Making stuff for myself is easier)
nctnico:
If you are going to make modules then I'd put TVS diodes across all the pins and use sockets. Zapping a chip due to ESD is done quickly.
HendriXML:

--- Quote from: nctnico on March 09, 2019, 03:06:49 pm ---If you are going to make modules then I'd put TVS diodes across all the pins and use sockets. Zapping a chip due to ESD is done quickly.

--- End quote ---
My hope is that TTL logic and pullup resistors of 15k at the inputs are enough to tackle the ESD zapping.

Didn’t know of TVS diodes, so thanks!

Having replaceable IC’s is probably the easiest solution. The IC’s are relatively cheap and not hard to check for proper working. To bad the turned pin arrays are to loose.
Gyro:

--- Quote from: HendriXML on March 08, 2019, 09:43:12 pm ---The output of this module will get LED's as Gyro suggested. The reason only this module will get output LEDs is mostly costs (time!). But also the importance of using encouraging to use other debug methods if needed. If there's always a very easy way to check a portion of the schematic, it's only human that the thinking goes down and the guessing goes up.

--- End quote ---

It will still be a bit of a mental leap (especially for a young mind) to understand that a lit LED actually signifies a low on the output of the inverter and hence a high on the input. You could include a 'hidden' inverter to ensure that a lit LED indicates a high output state with less effort than a separate 'display' module.

Edit: Alternatively, if you did do a separate indicator module, then you could drive the LEDs with a simple common emitter transistor stage with high enough input resistance to give a 'true' indication, even with the weak source capability of 74LSxx.


Without wishing to harp on about logic families again... Regarding the logic family. If you were to use 74HC CMOS, then you could introduce a fair amount of ESD protection by employing the internal protection diodes already within the ICs in combination with a series resistor. The protection diodes are normally good for 5mA continuous (higher in ESD pulse), so with, say, 100k series resistors, you would get a reasonable level of protection (in fact the threshold might become the insulation breakdown voltage of the resistor). In normal high speed circuits, such high value resistors would cause unacceptable slowdown, but not for a 'static' trainer.
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod