Cheaper Teensy Alternative?

[recon8659]

I recently cut apart an AT101W in order to make a 61 key keyboard, but I was wondering if this
https://www.amazon.com/gp/product/B012FOV17O
would be a viable alternative to the Teensy.

Thanks for the help in advance

[Wodan]

Yes, it's a ProMicro:
workshop-f7/how-to-use-a-pro-micro-as-a ... t=promicro

[recon8659]

Yes, it's a ProMicro:
workshop-f7/how-to-use-a-pro-micro-as-a ... t=promicro

ah. thank you so much

[Wodan]

Thank Scottc, he did all the research

[recon8659]

Thank Scottc, he did all the research

Another quick question if you know the answer, since this has about 18 usable pins, from my basic grasp, does that mean a keyboard matrix could use 9*9=81 possible inputs/keys, or does that mean it would be able to accept 18*18=alot of possible keys.

ty

[scottc]

I think it's something like 14 usable keys, don't remember whether that's accurate though

[recon8659]

I think it's something like 14 usable keys, don't remember whether that's accurate though

14? that can't be all can it?

[scottc]

Sorry, brainfart. I mean usable PINS, not keys. I think there was discussion in the thread about the number of pins, but can't find it.

[recon8659]

Sorry, brainfart. I mean usable PINS, not keys. I think there was discussion in the thread about the number of pins, but can't find it.

So the power for all of them would come from the VCC, and all the inputs would be, if its 14 inputs, up to 14 squared which is 196 keys?

[recon8659]

Sorry, brainfart. I mean usable PINS, not keys. I think there was discussion in the thread about the number of pins, but can't find it.

So the power for all of them would come from the VCC, and all the inputs would be, if its 14 inputs, up to 14 squared which is 196 keys?

that doesnt make sense to me anymore, would all the pins actually go to a ground?

[scottc]

No...

14 pins would mean at most a matrix of 7 x 7 = 49 keys. I'm not sure about the actual number of usable pins, but it's low compared to a Teensy.

Edit: You can get Teensy clones from China for like $10-13 if you need the extra pins and really can't afford a Teensy.

[recon8659]

oh thats unfortunate, so I would need to find a board with at least 16 I/O pins

[scottc]

Like I said, I'm not 100% sure about the number of usable pins. That's something you'd need to verify before making a decision.

[Findecanor]

The Arduino Pro Micro has 18 bidirectional digital pins. Some pins on the AVR can also be used for special purposes such as serial, timer input, PWM output, etc. and they are therefore sometimes labelled by those functions which can be confusing.
Arduino makes it even more confusing in that it does not necessarily map its pin numbers to AVR ports and bits in any sensible way and I think it can be different for each Arduino board.
Here is the mapping:

ArduinoProMicroPinout.png (343.29 KiB) Viewed 8677 times

In the figure above, Pxy stands for digital port x, bity.

Unlike the Teensy 2.0, The Arduino Pro Micro is made to run on batteries so it has a built-in voltage regulator.
There are two variants of the Pro Micro: One which feeds the AVR 3.3V, and one which is made to feed it 5V - the 5V version being the most common. If it does not say, it should be the 5V version.
If you do feed it with +5.0V from USB, however, there is a penalty - the voltage regulator will deliver only +4.9V.
The AVR should run well on 4.9V, but you could also bypass the voltage regulator by bridging J1 with solder.
RAW = +5V from the USB port (or power IN if you use battery). VCC = +4.9V (or 3.3V) from the voltage regulator, or +5V if bypassed.
On 3.3V, the AVR is limited to 8 MHz and the firmware needs to be made for it but since most firmwares are made for the Teensy 2.0 which runs always on 5V, if you have the 3.3V of the Pro Micro you should bridge J1 to run that firmware.

There is a thread in the Workshop area How to use a Pro Micro as a cheap controller/converter with more discussion and info.
(This thread too belongs in the Workshop )

Edit: I saw now that the other thread was already linked to. Sorry

[Laser]

You could try this one (more pins) https://www.arduino.cc/en/Main/arduinoBoardMicro (arduido micro, NOT pro, with reset button). I used it instead of a teensy with soarer's controller to revive a Bigfoot (model f keyboard). See here: post192171.html#p192171 (two posts below, there's a table whose first 2 columns show the mapping between the pin notations for teensy vs. arduino micro)