featuring Raspberry Pi Zero and "Retropie"
Link to page in German
I found this little beauty on Thingiverse and could't resist the temptation to give it a try myself. Before I go on, I'd like to thank Rasmus Hauschild, r1cebank, helljumper078 and The_Real_Phoenix. It was their contributions that made it possible for me to get this working. Great job guys!
If you like, just scan the code to get directly to one of those
Let's start with a list of electronical parts:
|Raspberry Pi Zero||
|1,5" OLED display||
|LiPo battery 1,2Ah||
Well YES! That's for sure no cheap project! I saw it more as a challange. I just wanted to see if I can manage and yes, I can!
A note before we start:
Get software installation, setup and modification done as far as possible BEFORE you place parts into the box.
Download-Link for installation, setup and modification of software
My Ultimaker transfers the STL-files from Thingiverse into the parts below. Material is PLA:
inner and outer displayframe
supportblock for PowerBoost 1000C
And most important the buttons. I used most designs unchanged.
Only the select/start-bar and colored buttons I found designed a bit too small.
So redesigned both to be slightly bigger.
If you like, download a Zip-file with changed/added STLs. For all original files go to Thingiverse and download there.
The schematic is fairly simple.Everything groups around the 40-pin GPIO-Port of Paspberry Pi. The Battery feeds directly the PowerBoost, who transfers 3,7V into 5V. The PowerBoost takes care of charging battery too, it just needs an ordinary 5V powersupply connected to the USB. The main-switch is shown as 3-pin toggle. Thats's actually overkill! 2-pin connection between EN and GND is enough. Once EN is disconnected from ground it goes up to +V by itself. There is an internal pull-up resistor.
The OLED-display is sort of overkill for this purpose. Thats why the extraordinary price-tag! It has a lot more funktionality (internal SD-card) than is needed here. It's the reason for using just 7 of 11 pins for thie project.
And there are 10 tactile switches of course. If you look at the schematic, the 2 at the left top are placed under select/start, the 4 left bottom are placed under D-Pad and the remaining 4 are for the colored buttons.
Raspberry Pi Zero V1.3. It's the version with camera-port (white port at the right side). That port is not needed but I couldn't get a cheaper old version.
Adafruits 1.5" screen is a cute little piece. It measures just 38 mm across.
The PowerBoost is available as 500 mA version too. For
the 1700 mA Battery the 1000 mA is better suited.
there are four colored SMD-LEDs: LOW(red)="battery low", chrg(yellow)="charging", chrg(green)="full", PWR(blue)="5V output activ"
Those are the tactile switches I used. Normally it should be
8x square-type (4-pin) and 2x slim 2-pin rectangular.
I like the round 2-pin better than 4-pin, so I took those instead.
This type was suggested as main-switch. I bought it and threw
it away! It's just crap, hardly 5 mm long and bearly to operate
with my fingers. I used a bigger one, that I had laying here spare.
Nothing special about the battery. It's just the size to fit into thr box.
I used some kind of proto-board to take on the tactiles. Getting it to right dimension is quite tricky.
Here you see why select/start tactiles must be slim. They won't fit otherwise.
Controller-board, ready wired. I had to redo the proto-board, because it turned out to small for the holding srews.
A solder-side view. There is a little bracket soldered to the board that holds and guides the wires.
When test-fitting the buttons and controller-board, it turned
out they were too close together.
To increase distance I glued 2 washers on top of each other to all four screw positions.
The right top corner is too tight, so I had to clip them a bit.
Checking all connections and basic operation before the Raspberry
goes into his final place.
The black unit underneath is a USB-Hub. It's there only temporary, used to connect keyboard
and WLAN at the same time.
This now was like Christmas and Easter the same time: It's alive!!!
Finally things go into the back-cover too. Underneath Raspberry
is a distanceplate (1.5 mm) glued, to raise the board
to correct positions. At the right bottom there is the PowerBooster support clued in place. For the main switch there is
another support added.
The wireing is complete. I removed the battery-socket from PowerBoost
to save space. To see the PowerBoost
color-LEDs I drilled three small holes into the back-covers right side. That shows the light nicely on the outside.
I found great difficulties when trying to fit front and back together. There is nothing to center both parts.
Moreover, wall thickness is not consistant between front and back! This was going to be a mess!
My solution was designing two additional parts (fittings), that
are glued to the small-sides of the front.
They both stick out about a 2 mm distance that goes into the yellow back. By doing so, they align both parts,
back and front. Now while pressing both together, I drilled 1.7 mm holes through the existing holes in the back
into the newly glued fittings. 4 metric screws M2x16 are used to (very carefully) screw the parts together.
Hallelujah friends, we are done!
Here it is in all its beauty:
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