T4.1 - connect bottom pads and SD-Card Pins to other PCB

MichaelB

Member
I am thinking about migrating my current (though neverending) project from T3.6 to T4.1.

Unfortunately I made use of almost all Pins of the 3.6 so I am running in some issues - which means I have to use every single pin T4.1 has to give.
I am sure I am not the only or first one who asked this but I could not find very much helpful information here. Correct me if I missed something.

Bottom Pads: (I will not need more RAM or flash memory)
Has anyone tried to solder a 1.27mm SMT pin header to the pads? Like this one:
https://www.digikey.de/de/products/detail/amphenol-cs-fci/20021121-00008C4LF/2209054
After some measurements this should work.

SD Card Pins: (I will not need the onboard SD card reader)
This will be more complicated I guess. I found tall-dogs solution:
https://www.tindie.com/products/loglow/micro-sd-breakout/
But this seems to be no longer available. And I am not sure how long lasting this will be if the device is used in a somehow not very solid (=car) environment...
If there was no card reader installed (like on the T4.0) it would be possible to connect e.g. some flexible pcb to these pins.

I think I will have to reduce the functionality of my device to save some pins, but at the moment I am trying to anything to find another solution.
Any weird ideas?
 
@MichaelB: On my <TeensyMIDIPolySynth>, I made use of the <SparkFun CD74HC4067 analog MUX breakout board> (allows 16 analog input or 16 analog output, or any combination of analog input/output signals to be sampled/driven from a single analog pin, with four digital pins for addressing . . . 16 pins needed becomes 5 pins used) for my analog signal inputs. I also (eventually) made use of the <SparkFun 74HC595 breakout board> for driving a large number of discrete LEDs plus 2 x 7-segment LED digital displays. With four pins (output enable, clear, clock, and data input) you can drive any number of outputs (unlimited pins needed becomes 4 pins used), plus you can modulate the output enable pin with a PWM signal to vary the brightness if you are driving LEDs, etc.

Hope that helps . . .

Good luck & have fun !!

Mark J Culross
KD5RXT
 
Back
Top