Planet Computers Gemini Review: Return of the PDA?

When it was made public that a company was going to crowdfund a PDA, I was sceptical. First off, PDAs where dead and had been for a while, but also, Crowdfunding can very easily go wrong. Fast forward a year or so, and at MWC this year I got a chance to speak to the people behind the Gemini, Planet Computers, and play with a prototype Gemini myself, and to say I was excited is an understatement. But did that excitement last throughout my review period? Let’s take a look at my full review of the Planet Computers Gemini.

Planet Computers Gemini
  • Decent Design
  • Great build Quality
  • USB-C!
  • Hacking and modding is encouraged
  • SoC is very power hungry
  • Screen could be better
  • Keys could be clickier
  • Only for a niche of a niche

Buy The Wifi and 4G Gemini from Planet!

Disclaimer: Planet Computers have loaned this unit to me for review, after the review is finished, this unit goes back to them. No money has changed hands between either party, and no one other than other MTT staff will see this content before it goes live.

Planet Computers Gemini Review


  • 5.99” IPS LCD 2160×1080
  • Scratch Resistant Glass (most likely Asahi DragonTrail glass)
  • MediaTek Helio X25
    • 2x Cortex A72 @2.5Ghz
    • 4x Cortex A53 @2.0Ghz
    • 4x Cortex A53 @1.55Ghz
    • Mali T880 MP4 GPU @850Mhz
  • 4GB RAM
  • 64GB eMMC storage
  • 802.11 b/g/n/ac 2.4Ghz and 5Ghz
  • 4G LTE (1/2/3/4/5/7/12/17/20/41)
  • VoLTE capable
  • 4220mAh embedded Battery
  • Dual USB-C ports

For more technical specifications, head on over to the Gemini Page on Planet computers.


Starting off with the hardware, the Gemini instantly conjures up memories of the Psion 5. The keyboard is stunningly close to it (in looks at least) and the shell is nice and robust as well with a mostly plastic build, but not feeling cheap and chintzy.

A tour of the device shows, first up, that we have a two piece lid. On the upper lid, there is a Planet Computers logo and that’s about it. The larger bottom panel is actually removable, and whilst it might look like you pry it up with the two little slits in the side, those are actually for the speakers. The extra chambers improve the volume. To remove this panel you need a special tool (which is in the box) that actually slides in between the two metal piece and pries it up. Under this panel, there is the MicroSD and MicroSIM slot (though I am told there is also the requisite hardware for an eSIM not yet activated)

Planet Computers Gemini Review

Beneath this panel also lies something quite interesting, an accessories port. Planet show this being used for an external camera module (as the Gemini doesn’t have an external camera), but hypothetically the accessory port could be used for adding a larger slice battery in.

Planet Computers Gemini Review

Closing the Gemini back up and moving to the sides, on the left we have a USB-C port for charging, a microphone and a 3.5mm headphone jack on the bottom half. Up top we have one of the two speakers. On the other side, swap the 3.5mm audio jack for a “voice assistant” button. This button is, well, strange. When I got my first Gemini unit, I assumed that it was broken, as this button is where most devices would have their power button, so I was jamming the button in, hoping to turn the thing on, It wasn’t until I opened the Gemini up and scanned the keyboard did I realise that the “Esc” button in the top left of the keyboard does triple duty as an Escape key, a power button and a screen lock key.

The rest of the Gemini outer shell is pretty boring. The front lip is used for getting the Gemini open, and the bottom is just a single piece of metal, mimicking the top. The rear however has a nice subtle piece of flair, a simple “Gemini By Planet Computers” decal is laser etched into the metal. Nice and subtle, nice and classy.

Planet Computers Gemini Review

Opening the Gemini up is where we see the appeal of the Gemini, the keyboard. In fact, I’ve tasked myself with writing the Gemini review on the Gemini as much as possible. Planet Computers tout this as a full tactile keyboard, and for the most part, I agree. It is small, but all the requisite keys are here, some keys pull triple duty, but that is fine. Just like learning to use the BlackBerry KEYone, some of the largest learning curves are learning the function modifiers, but once you’ve got those down, you’d be surprised at the speed you can type at on the Gemini, whether it be thumb typing, or with it on a desk and using your fingers just like a miniature laptop.

Planet Computers Gemini Review

Where I take issue with what Planet says is a tactile keyboard. Let me start off by saying that the Gemini I have here (which is actually my second unit) is much much much improved from the first unit I got to test, and even noticeably more so than the unit I got to test at MWC, but I would not yet characterise the typing experience on the Gemini as tactile. The keys do bottom out and there is a sense of a “bump” in the key switch, but it still feels a little too mushy for my liking. I’m not asking for Cherry MX Blues here (or the super low profile Kailh PG1350 switches) but I need a little more actuation resistance and a more audible actuation sound before I can comfortably start calling this a tactile keyboard.

On the upper part of the clamshell, we have the screen, which has changed from the early units. Originally Planet Computers had meant to ship the Gemini with a 5.7” QHD (2560×1440) screen, but later in the development cycle was able to switch to a 6” 18:9 panel with a resolution of 2160×1080. I like this change. I’m a fan of 18:9 screens, and I even think Planet might have been able to go even bigger if they had changed some things. If Planet is up to changing the aspect ratio, a 6.3” 19:9 panel might be a better choice, but an ideal one could be a 21:9 panel like we are seeing more desktop’s move to, with a 2560×1080 resolution. The GPU wouldn’t incur much more load and the user would get extra width for the screen. If we wanted to go crazy though, one of the better options might be a 3:2 screen, such as what BlackBerry is doing with the KEYone and what more Laptops are moving to, such as the MateBook X Pro from Huawei and all the recent Surface devices from Microsoft. In doing this however they would have to increase the depth of the keyboard, changing the shape when closed. It is all about trade-offs, and for the most part, I think the Planet team made the right ones.

Planet Computers Gemini Review

Talking about the actual screen quality, I feel it is adequate. Just like the keyboard, which is good, but could be improved, I feel the same about the screen. The IPS screen gets reasonably bright, and I have no problems with the resolution, but especially after using the Huawei Mate 10 Pro and The Huawei P20 Pro with their stellar OLED screens (the Mate 10 Pro is the same size as the Gemini!) the Gemini’s screen just feels a little underwhelming, especially in tighter viewing angles. The viewing angle “issue” (it is really not an issue) is exacerbated when you realise that the Gemini screen only locks open at a single angle, and if you aren’t at a favourable angle, you’re likely going to end up holding it in your hands and thumb typing.

Overall, hardware wise, the Gemini hits more than it misses, but where it misses, it misses by some distance.


Software-wise, the Gemini is actually quite interesting. At its base, the Gemini is a super small Android laptop that can also act as your phone (though, if you do use it that way, I’d recommend picking up a smartwatch). But that is not all, one of the big promises of the Gemini is its ecosystem outside of Android. You can actually install a build of Debian on the Gemini, and it works just like a small Debian laptop, and any programs compiled for ARM work here, which on Linux is far more than you’d think.

Planet Computers Gemini Review

Starting with what comes on it from the factory, the Gemini starts with a Build of Android that, at this point, is outdated. Android 7.1.1 is old, and the February Security patch is 3 months out of date as well. Part of the problem here is the MediaTek chipset. Whilst the Helio X25 is a decently powerful chipset, MediaTek aren’t known in the industry for timely source code and updates. I want to see the Gemini with Oreo, or even whatever P ends up being called, but whilst we may see that, I wouldn’t count on seeing it officially in any meaningful time frame.

Planet Computers Gemini Review

On top of Android though, Planet Computers haven’t messed with much. They’ve brought the old Psion dock back, and it’s summonable via the Planet key on the left hand of the spacebar. This Dock is customisable to whatever you’d like, can be auto hidden or always there, a nice little dock that I honestly thought I’d never use, but the more I used the Gemini, the more I was actually using the Dock.

Planet Computers Gemini Review

Planet also have a few apps of their own on the Gemini, one of the best ones, in my opinion, is the LEDison app. LEDison enables you to customise the “Knight Rider” LED back in between the two metal panels on the lid to whatever you want. You can change the LED colour, you change the intensity, the interval between flashes etc. A highly geeky and customisable app, but if you’re using the Gemini as a phone, this could be set to colour code to contacts, or apps, so even if you don’t use a Smartwatch with it (though, we recommend you do) you can still have a piece of information with the clamshell closed (though, it’d be interesting if someone creates an addon for the Gemini Accessory port with a monochrome OLED or E-Ink screen for things like this).

Planet Computers Gemini Review

Whilst I wasn’t able to test the Debian build on my Gemini (time ran out) the build I saw at MWC was surprisingly stable, and as just ironing out performance with hard-coded HW accelerated GPU drivers, the guru behind this (and he really is a guru) is working hard, and we will update this if we can.

The best part about all of this? Gemini won’t chastise you for doing this, in fact, they’re all geeks and tinkerers as well, they even sent me a guide on how to do it, and I would have, had my timetable not gotten so busy. Last note on Software, save yourself, do not open the Pac-Man app in the Planet dock, otherwise, like myself and my PR person for Planet, you’ll be addicted.


This is actually an easy section to write for once. The Gemini performs really well for the most part.  The Helio X27 inside of it isn’t the newest (it actually came out in March of 2016), but it still uses some high-performance Cortex A72 cores, 2 of them in fact clocked at a whopping 2.6Ghz, as well as 8 Cortex A53s in varying clock clusters.

The problem with the Helio X27 isn’t the power it has, it’s the Power it uses. The Gemini’s processor is built on a very short-lived 20nm Planar process node from TSMC. 20nm Planar was not well received and was hailed as one of the worst in recent memory. The density increase wasn’t worth it from 28nm, the power increase most certainly wasn’t. The power leakage was out of control, let’s just say there is a reason everyone jumped on to FinFET as early as they could after this massive failure.

You may ask why I bring this up, and it’s because even with a fairly large 4220mAh battery, the longevity of the Gemini isn’t all that great. I was expecting it to lean closer to Laptop than to smartphone, but honestly, if I used it as a smartphone like I did for a few days, the battery life was quite underwhelming, where even 12 hours of use was able to sap the battery into the emergency mode. Using the Gemini as a secondary device was much better, but was still a 2 day device rather than longer.

On another negative, the Mali T880 GPU is ancient, and even worse is the 4 core configuration that MediaTek have put it in. I’m not asking for Gemini to have added in a Snapdragon 845 into this, but a newer chip from Samsung, or even a newer MediaTek chip would have made more sense than this rapidly ageing chip.


I touched on this a little in the performance section, but I’ll extrapolate a little more here. Battery Life on the Gemini isn’t great for any continuous use. Burst workloads favour this, but not as much as you’d think/hope. I was continuously seeing 3 days of standby, but as soon as I actually started to sue the Gemini, getting over 3 hours of screen on time was hard.

Part of this is because of the inefficiencies of the helio X25 processor itself, another is that it is likely that the screen on the Gemini consumes a fair bit of power, as I am unable to track down who makes it, but it is the highest power consumer of any electronic device.

It’s also possible that Planet themselves haven’t really optimised the Android build all that well, though this is the least likely. With the amount of effort they’re putting into software development on this thing, it’d seem weird to me that they’d skimp on the most important part of a portable gadget.

Planet Computers Gemini Review

Lastly, I want to talk about Charging. The Gemini will work with any USB-C charger, though, you need to plug it into the left hand USB-C port. To cut down on costs, only one of these USB-C ports are wired for power. That’s fine, a small gadget like this I can deal with. Interestingly though, the Gemini appears to be using MediaTek’s proprietary fast charging tech called PumpExpress Plus (often abbreviated to PE+). Now this is the first device I’ve ever seen to use it (though I know there are others) but the Gemini, under the right conditions, can charge at 15w which is impressive. More impressive to me is doing it at 12v! 12v 1.25a is an intriguing way to go, as we’ve seen Huawei with SuperCharge and Oppo with VOOC move to lower voltage and higher amperage. The benefit of this method is that it’s easier to get cables that support 12v and a smaller current than it is to get a cable that supports pushing 5 amps of juice, that’ll just melt other cables. But for shiggles (you can figure that abbreviation out yourselves) here is a picture of the Gemini wall plug showing the voltages and amperage it supports.


This is usually an easy part to write, but for the Gemini, I’m a bit torn. I do really like the Gemini, despite its flaws, but the problem for me is that it is duplicative. Everything the Gemini wants to do, I can do on my KEYone, and that has a keyboard I prefer, it also has a newer processor, so the smaller battery (with a minutely lower screen resolution) is negated giving it better battery life.

Planet Computers Gemini Review

Can I recommend the Gemini? As the product currently stands, not really. I went into this review really excited and wanting to own one, and I leave it looking forward to a second generation, but not wanting to drop $500 on a first generation product. The Gemini does very little wrong, which is impressive for a new company’s first product. The problem is that it doesn’t do a whole lot outstandingly well either.

Here’s to Gemini: The Next Generation!

About Domenico Lamberti

Technology has been a big part of my life for years, whether it be ripping the family computer apart to see how it worked, playing with the new phones that Dad brought home from work. Senior Reviewer for MTT.

One comment

  1. Intredasting.

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