About my Pocket PiGRRL
Ever since I saw the video on this on the Adafruit YouTube channel, I had to make one.
I'm a massive fan of retro games and the Raspberry Pi is perfect for this sort of project.
This is my first major project I've finished and can take pride in knowing I did it myself. It was also my first serious attempt at soldering anything. I learned a lot from this and can't wait to get onto my next one!
Printing the Parts
I had some fun times trying to get the parts looking great. In the end I had to settle for second-rate quality just because I didn't have what I needed to make it look good.
Top and Bottom
Both printed without a hitch in black PLA, but I found that I was having clearance problems on the first layer, where the holes for buttons etc should go. After struggling a fair bit to understand why it was happening I ended up using a knife to cut the holes larger.
Late in the piece I had a real hard time with the final screw hole that joins the two pieces. I finally loaded up the drawing from Autodesk 123D and edited the model in Fusion 360 to make the hole bigger. If I get the chance to do it again I'll redo all the holes larger.
I really love the colour scheme on the XBOX controllers. So I matched it. I used some 3mm filament from the 3doodler printing pen. It was just enough to print a button in each colour without having to buy a full roll for just 4 buttons.
The D-Pad and Top buttons were something different. I decided I didn't like the finish on the buttons using TPE (Ninjaflex). What I did was print the first 1mm (or about 5 layers) in TPE and then pause the print and finish the rest in PLA. It resulted in some good squishy buttons with hard tops. I'm quite happy with the result.
Sourcing the Non-Printed Parts
You don't get everything you need in the Adafruit kit. It does have most of the stuff you need but some essentials are harder to get. Especially if you don't live in the US. I had a really hard time finding non-metric (ie imperial) screws in Australia. I did find some in the end but it was from an obscure company online that I wasn't entirely comfortable buying from. Same deal with the magnets. So now I have hundreds of screws and about 50 magnets that I'll probably never need again.
The rest of the stuff I pretty much had, in one way or another.
In hindsight the build is quite simple, although still rather difficult for a beginner. This was pretty much my first major electronics project.
I had it in my mind that I would use heatshrink and make everything as neat as possible everywhere. After a while and a lot of frustration that idea went out the window.
I had to scrape out a bit of the hole where the switch went in to make it fit. The class D amplifier did not live up to expectations. I was getting a really tinny sound out of the speaker. I thought it may have been the speaker so I replaced it, but it did not improve. It may have been my dodgy soldering but I didn't expect that to impact the sound so greatly.
Getting all the screws in is quite a task. I could never get them in perfectly since they cut through the pcb plastic and just continually rotate without actually screwing in. I think standoffs would have been a better way to do it.
The Buttons were the hardest part. I didn't own a Dremel or anything that could cut through the perfboard. I had to put the project on hold until I could afford to buy a dremel (something that I had wanted for a while anyway). It made light work of cutting afterwards. The key to having a decent finish on the handheld is to get the buttons right. You really really want to make sure they are level and all neat. I didn't do this and now my buttons look wonky and don't feel really nice.
My soldering leaves a lot to be desired for :/
Lastly I found it difficult to manage the wires off the ribbon, I can't imagine how many mistakes I would have made if I wrapped them together like in the tutorial.
What I'd do differently next time
First things first - top quality Filament. I have heard good things about Colorfabb, maybe I'll give that a shot. Filament is expensive in Australia so I need to make it count.
I'd redesign in Fusion 360. It's fortunate that Fusion 360 is compatible with 123d.
- Standoffs for the PCB's in the bottom halve.
- Larger hole for joining screw
- Larger clearance for the switch
- Larger clearance for the buttons
- Move the speaker holder down a little
I've seen some people have put volume control on. It wouldn't be too hard to do, you could also use a stereo amp too.
I think I'd like to have a go at creating my own Button PCB. Ultimately a PCB combining the buttons, Power Supply and Amplifier would be amazing, but beyond my level of experience at this stage. I think I'll start with buttons.
Using tac switches for the buttons is a good idea - but they sound awful and don't feel very nice to press.
My idea is that the PCB would have gaps between traces and the buttons would have metal (maybe aluminium foil?) stuck under them. When they are pushed down on the pcb it completes the circuit for that button. This would result in a much nicer feel for the buttons and having a pcb with the ribbon attached at the top would reduce the amount of soldering too. I'll have to pull apart my xbox controller and see how they do it.
Other things I'd like to try - a wide format form factor. You'll see in my photos I've already started to experiment with this idea. I need to save up some more money before I can take this idea further. I'm planning on incorporating my custom PCB design into this form factor.
Thanks to Adafruit and Noé Ruiz for coming up with this great product and they have inspired me to continue with creating great toys and gadgets using electronics and 3d printing!
Sorry for all the text, but I know that when I was first researching this topic I wanted to read as much as I could about it. I also hope you like the photos, I'm no photographer and they were taken on my phone in bad lighting, but I hope it highlights some of the difficulty I had as a beginner with limited tools and resources.