MintyPi Build Without Helder's Boards!

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AnotherUsername
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MintyPi Build Without Helder's Boards!

Post by AnotherUsername » Tue Sep 05, 2017 11:10 am

TLDR; What I thought would be a weekend project turned into a two month long learning experience.

I've been putting together my own MintyPi using pieces and parts I could find locally while Helder's parts were out of stock. It's been a beast of a project but I've been learning a lot and it's been a ton of fun. First, a list of my materials:

1 x Graphing Calculator - It's a casio fx-9860gii. I tore this down to use for the buttons on the PCB https://www.amazon.com/Casio-fx-9860GII ... B0023I9QCU
1 x Set of 3D printed parts
1 x 80 pin CD-ROM ribbon cable. I harvested mine from an old Dell PowerEdge I had laying around. It looks like this: http://www.pcguide.com/ref/hdd/if/ide/z ... able80.jpg
2 x 6mm-6mm-6mm buttons for L and R. Got locally.
2 x 6mm-6mm-7mm buttons for start and select Again, locally.
1 x 5v 1A Micro Lipo battery charger. I picked up these from amazon: https://www.amazon.com/gp/product/B01DR ... UTF8&psc=1
1 x 3.7V 1200mAh battery. I got mine here: https://www.amazon.com/gp/product/B06W2 ... UTF8&psc=1
1 x 2.2" TFT SPI Screen. Got it here: https://www.amazon.com/gp/product/B01N3 ... UTF8&psc=1
1 x Conductive pads for button PCBs. https://www.amazon.com/gp/product/B06W2 ... UTF8&psc=1
1 x Set of replacement buttons for NDSL. I got a set without start and select http://www.ebay.com/itm/FIX-PARTS-Contr ... 2749.l2649
1 x 0.5 W 8 Ohm 20 mm speaker. https://www.amazon.com/gp/product/B00QC ... UTF8&psc=1
1 x USB Sound Card. https://www.amazon.com/gp/product/B01CZ ... UTF8&psc=1
1 x SPDT On/Off switch. Got mine from a local electronics supply store, and I also harvested some from old electronics.

First, I traced the conductive pads onto the calculator PCB and cut them out using a small hack saw. I originally tried using wire cutters but this would generally make the board shatter as opposed to making clean cuts. I then use copper tape to hold the wires onto the conductive traces.
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I also had another method of making button PCBs using protoboard and copper tape. I followed the same process as before, except this time I used thin strips of copper tape to create the traces the conductive pads will complete. A more complete guide can be found here:
http://www.sudomod.com/forum/viewtopic.php?f=34&t=4095

Next I went ahead and wired up the speaker. Pro tip, glue your speaker in BEFORE the button PCBs. :mrgreen:
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Now glue down the Start + Select, and button PCBs down to the face plate.
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The screen wiring was next. I broke down an 80 pin ribbon cable into strands of 9 wires and wired that to the screen and the Pi.
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Next was the L/R buttons, and battery/charger. Glue those down in just like Wermy's guide.

Once those are in, go ahead and screw the Pi to the button plate.
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Now wire up the button PCBs and Start + Select.

Put in the sound card and get all the wires ready for soldering. If you've managed to be careful with your button PCBs, you should be able to fit everything without removing the crystal.
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I've been able to get one put together without sound as I'm still waiting on the sound cards to come in. This is a very much in progress build. I'll post pictures as well as the build log as I go.

Thanks to Wermy and Helder for all their work.
Last edited by AnotherUsername on Tue Sep 19, 2017 9:43 am, edited 4 times in total.

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dryja123
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Re: MintyPi Build Without Helder's Boards!

Post by dryja123 » Tue Sep 05, 2017 3:46 pm

Looking forward to seeing this completed! I've been ordering sound cards in China and been receiving them via free air shipping to the US in a little over a week.

Here's the link to the guy who's been selling them to me, I've ordered multiple times with a quick turnaround: http://www.ebay.com/itm/112304879364

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Re: MintyPi Build Without Helder's Boards!

Post by AnotherUsername » Thu Sep 07, 2017 11:23 am

The build has been going along alright. I got the sound cards in, but I've been struggling to get them to work. I have them wired up, but I'm not getting any sound and it looks like I get messages about failed to attach to default sound card. At first I thought it might be because I bridged the data connection at the test pads, but it's hard to tell for sure because those pads test positive for continuity even before wiring the card to it...

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Re: MintyPi Build Without Helder's Boards!

Post by AnotherUsername » Thu Sep 07, 2017 1:29 pm

*EDIT

Turns out the issue was that the R8 SMD resistor component came off. Looks like I'm getting another sound card!

Time2Strike
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Re: MintyPi Build Without Helder's Boards!

Post by Time2Strike » Sat Aug 25, 2018 7:07 pm

I have a question on this thing, I want to do almost the same (and I think the button wiring is AWESOME) but do you have a diagram how you hook the cable up to the zero? I cant find this info, thanks for your help

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rodocop
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Re: MintyPi Build Without Helder's Boards!

Post by rodocop » Wed Aug 29, 2018 8:59 am

Time2Strike wrote:
Sat Aug 25, 2018 7:07 pm
I have a question on this thing, I want to do almost the same (and I think the button wiring is AWESOME) but do you have a diagram how you hook the cable up to the zero? I cant find this info, thanks for your help
Connecting wires to the pi is simple, you can just the guide on adafruit for the retrogame utility. If you plan on using the minty pi image use these GPIO pins (the numbers are the GPIO numbers, not the physical pin numbers):

https://learn.adafruit.com/retro-gaming ... s-software

LEFT 14 # Joypad left
RIGHT 22 # Joypad right
UP 4 # Joypad up
DOWN 5 # Joypad down
LEFTCTRL 21 # 'A' button
LEFTALT 16 # 'B' button
Z 26 # 'X' button
X 20 # 'Y' button
SPACE 15 # 'Select' button
ENTER 19 # 'Start' button
A 12 # Left shoulder button
S 6 # Right shoulder button
#ESC 17 # Exit ROM; PiTFT Button 1

As for the screen wiring, you'll use the 9 pins in the middle of the GPIO strip, more info can be seen here:
https://sudomod.com/forum/viewtopic.php?t=2312
Display--------Raspberry Pi
BL--------------GPIO 18
SCK------------GPIO 11
MISO----------GPIO 9
MOSI----------GPIO 10
CS--------------GPIO 8
RST------------GPIO 25
D/C-------------GPIO 24
VIN-------------pin 17 (3.3v)
GND-----------pin 20 (GND)

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