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Playable electronic modules - modules in action
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Gyro:

--- Quote from: HendriXML on March 08, 2019, 01:07:34 am ---I recreated the gate stickers, they now in portrait stand. This allow a better view on the symbols. The power connectors do not block the view as well.

I've one rev 2.0 case done, it takes 3,5 hours to print. Estimate cost was about 0.80 euro.

I'm still struggling with how to mount the magnets. The coating on them makes them hard to glue, but it can be done with superglue they say (degrease, fine grain sanding). However that is of a later concern.

The new case has more margin so the PCB/case is not under any tension anymore. The hex screws can be tightened a lot, I'm pleased with that choice.

Next step is to resolder the XOR example and give it a new sticker. The headers will be soldered after applying the sticker. I don't want any burn-marks any more.

--- End quote ---

You've forgotten to include (multiple) VCC and GND pins for tying inputs high or low.

P.S. You could also do with adding a multiple LED block for easy monitoring of output states. If still using LS TTL then I suggest driving them with a 74LS04 inverter so that the LEDs light for logic High.

P.P.S. If you provide multiple pins for each output, then it would be much easier to connect multiple jumpers for combinatorial logic. With single pins and female jumpers it's going to be very hard to, say, connect one output to more than one input.
HendriXML:
 :blah:
--- Quote from: Gyro on March 08, 2019, 11:25:00 am ---You've forgotten to include (multiple) VCC and GND pins for tying inputs high or low.

--- End quote ---
I think that is still a good idea, but my goal is at first to have the modules (visually) as simple as possible.
With almost no possibility to connect things the wrong way. (The pins are now also protected by a wall, so there’s almost no room to add extra’s without compressing the layout)

The highs and lows could in the current setup come from another module. I’m thinking about giving the inverter module a double function. Which with no input connected would output a low. And having a 2 pin connector at the input side, one as the inverter input, one a ground pin. So it would be possible to either use or jumper or a switch on a wire to create a high output, or use an active input.

That solution is not really short circuit safe. So I’m still thinking on it. (It should visually also be easy to understand).

For one output to many input relations I’ve made splitter wires. (1 to 3) These are easy to make from 2 normal ones and thus also cheap.
HendriXML:
I recreated the stickers.

I went for the KiCad color scheme. (Have to check if it prints ok on sticker paper).

I altered the inverter module to have its dual function. The ground symbol is made extra meaningfull, it is even more like a down arrow making the input low. So that will be easy to remember.

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.
HendriXML:
One way to have a perfect fitting sticker is to use the pins to align the sticker with the PCB. But also start with a larger sticker and cut (with the sticker downwards) using the PCB as a ruler.
HendriXML:
So the inverter modules will get a ground pin. It is however possible that an output of another module is accidentally connected to that pin. I’ve read that a gate IC can have one output short circuited for only one second. But also because it is almost impossible to replace them I want the best chances of surviving a short circuit.
So I thought is would be better to have a 100 ohm resistor between the “groundpin” and ground. With a pullup resistor of 15k that would be small enough to get a low signal when using a switch or jumper.

Are there alternatives (besides moving the resistor to the outputs)? There’s very little room left on the PCB.

My initial thought was just to replace the IC. But the turned pins I got to make that easy are just to loose around the IC legs. The IC would simply fall out with a good shake. I probably ordered LQ ones (aliex).
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