Game Tin - A Batteryless Handheld Gaming Device

[shifthack]

Background

I've wanted to do a project built around an ultracapacitor for a while now. I finally decided to do it and the Game Tin is the result. The Game Tin is a handheld gaming device that is designed to mount inside of an Altoids Smalls mint tin. I incorporated solar cells to augment the limited energy capacity of the ultracapacitor.

Here is a picture of a Game Tin prototype unit put together and mounted in the Altoids smalls tin.



Features

• Fully charge in 30 seconds via USB
• Stay charged indefinitely outdoors via solar energy
• Hours of runtime on a single charge when no solar energy is available
• Download and store games and applications
• Eco-concious design
• Open source hardware and software

Here is a picture of the Game Tin prototype PCBs with parts populated.



Tech Specs

• 128x128 pixel Sharp memory display
• EFM32GG332F1024 microcontroller
• 48 MHz ARM Cortex M3
• 128 KB RAM
• 1 MB Flash
• Silicone gamepad buttons
• USB Micro B port
• Solar cells (total 44.6 mW power @ Maximum Power Point in 1 sun conditions)
• 10F ultracapacitor with 9mWhr capacity

Current Status

The Game Tin is still a work in progress but I have some data to share. So far I've ported one game to the platform that was originally targeting the Hackvision Arduino platform. The game is Poofy Adventure and it is a platformer style game. It will serve as a nice test bed for making power optimizations as it is fairly well suited to taking advantage of the memory display. Currently it is not optimized to take advantage of the memory display or other low power features of the hardware. Given that, it has a 1.5 hour runtime off of the ultracapacitor alone with no solar contribution. Outdoors in good sunlight, it will run indefinitely. I'm looking forward to seeing what I can get after optimizing it.

I have more information on my website including a blog talking about various aspects of development and testing. Check it out if you are interested.

Game Tin Website

To make things easy, I'll also include a link here to the source files. The schematic capture and PCB design is being done in KiCad. Here is where you can find links to all of the repositories.

Source files

I am looking to see if there would be enough interest to warrant a small production run eventually. I have a sign-up form on my website you can use to indicate you are interested. I'd be happy to hear some feedback and answer any questions you may have.

[fcb]

Looks like a well executed project, well done.

[shifthack]

Thanks!

[tom66]

Very nice!
Out of interest, how much current did you find the Memory LCDs ate up when displaying only a static image (not updating?)
Sharp claim 15uA IIRC... which is pretty good, but curious if this is ideal or real world.

[shifthack]

Thanks! The display datasheet [1] specifies a typical power consumption of 12 uW for a static image. At 3.3 V, this would be 3.64 uA. Energy Micro Application Note AN0048 [2] reported an average current consumption of 1.9 uA on the STK3700 development board with the display showing a static image. Here is a description of the setup from the application note.

A static image is shown to illustrate that no CPU intervention is required to keep this image on the screen. The EFM32 can continuously stay in EM2 while the LETIMER is toggling the EXTCOMIN pin and LESENSE is monitoring the touch slider. The image is only sent once to the display.

Note that the EXTCOMIN pin of the display must be periodically toggled even when a static image is being displayed. I did a similar experiment on the STK3700 except with no monitoring of the touch slider. I measured an average current of 2.5 uA for the total circuit (microcontroller & memory display) using the development board's Advanced Energy Monitor.

In any case, I can confirm that the numbers in the datasheet are not just ideal. I was coming in under the specified typical power consumption even when including the power consumption of the microcontroller toggling EXTCOMIN.

[Legit-Design]

Spotted a small problem. How long will those memory displays last on harsh direct sunlight? As far as I know normal LCD and TFT panels tend to lose their polarizer after too much sunlight and after that you cannot see the screen anymore. Also in the memory lcd datasheet it says that should not be stored in direct sunlight. So display next to solar panels that should be pointed towards the sun.

[shifthack]

Ya, that's definitely a possible issue. I noticed that in the datasheet as well. I haven't found any data regarding the exposure times and how long it would take to damage the display. I'll see if I can get any data from Sharp. Another issue with the current enclosure is possible ESD damage to the display. Maybe some kind of bezel over the LCD could add additional UV protection and protect against ESD? The only problem with that is another custom part to deal with and added cost.

[Legit-Design]

Ya, that's definitely a possible issue. I noticed that in the datasheet as well. I haven't found any data regarding the exposure times and how long it would take to damage the display. I'll see if I can get any data from Sharp. Another issue with the current enclosure is possible ESD damage to the display. Maybe some kind of bezel over the LCD could add additional UV protection and protect against ESD? The only problem with that is another custom part to deal with and added cost.

Stick one display outside as a test for months if possible. Just make it weather tight but leave the display exposed like it's suppose to be. Maybe something to track the sun like with tracking solar panels so it gets maximum exposure. Or use magnifying glass that collects several times the suns energy and have one tested in no time that way.

Thin laser cut acrylic shield with screw holes on the pcb to mount it down for the product? I'm not sure but I think you can get some that mostly block the harmful radiation. Many opensource/small volume stuff seems to use laser cut acrylic these days.

[fcb]

Can you mount the solar cells on the outside of the tin?