It's MeArm Pi on Kickstarter

Kickstarter can be a wonderful place to support great new ideas. One project that has sprung up and captured the hearts, minds (and pledges) of folk is MeArm Pi from Mime Industries. Following on from the very successful original MeArm robot arm Mime are presenting something great to the Raspberry Pi community. The project has already smashed it's £10k goal with almost £47k pledged at the time of writing. Doing the maths on the pledges that represents 844 arms at present. That's a lot of robotic hands to shake! Best of all: you still have until 6pm on March 8 to support the project and acquire your very own robot arm.

Mime describes MeArm Pi as "easy to assemble and not requiring extensive knowledge of electronics, the MeArm Pi STEM kit helps kids and adults learn robotics and teaches them how to code." That's cool. Very cool: robot arms are fun, programming is fun, and programming robot arms is twice the fun.

MeArm Pi

I briefly interviewed Ben Pirt joint founder of Mime. His passion for the new MeArm is clear: a desire to create a functioning robotic arm platform that simplifies the construction process enormously.

CD: What was the motivation to change the design of MeArm for MeArm Pi?

Ben: "The first MeArm has been built thousands of times (including a fair few times ourself!) and we wanted to broaden its appeal and try get even more children involved in making and programming it. So we decided to look at which parts of the build were particularly difficult. The number of screws came out as a big issue that was catching people out so we tried to re-work the design wherever possible not to need screws. Now the only screws left are on the joints where two pieces hinge together. The grip had a major re-work (from 9 screws down to 1) which made it much simpler to build."

It's worth pausing and considering this: the number of screws and fiddly components in a build really can influence the complexity and hence accessibility of the product. When I received the Maplin robot arm for Christmas a few years back I spent several hours putting together gear boxes, ensuring all was aligned and assembling the thing. While highly enjoyable in its own way (who doesn't like to build things) it was also frustrating: that's a lot of components to assemble *just* to get a fairly simple robot arm up and running! Mime's keen attempt to solve this build complexity problem is admirable.

Once I had built the Maplin arm I wanted to program it using a record and playback mechanism in Python. It was at this point I hit a few snags as precision playback just isn't easily possible with normal motors, and again it looks like MeArm Pi has overcome this issue.

CD: How accurate are the servos with MeArm Pi, i.e.: can you reliably pre-program repeatable movements?

Ben: "The servos are pretty accurate - they use metal gears for extra reliability. The big difference from the Maplin arm is that servos can be relied upon to be nicely repeatable so you can program them to do things again and again. Servos won’t drift out of calibration like motors."

Having non-drifting motors sounds like a dream come true! Don't get me wrong: I love the Maplin arm and easily recommend it to everyone as a low-cost way to get into robotics on the Raspberry Pi. Now though, Mime are offering a viable alternative that combines the hardware with ease of programming. Talking of programming, I asked Ben what else makes the MeArm so great:

Ben: "I think there are a lot of things that make the MeArm Pi better than the Maplin arm:
  • children build it themselves so they get a better understanding of how the mechanics works
  • the motor control is easier from the Raspberry Pi and can be programmed in any number of programming languages
  • the software is better and more suited to beginners"

It's worth noting that supplying purpose built control software to get up and running quickly is a great idea: it's what makes projects like Pi-Top so readily accessible for instance. Software for the Maplin arm does exist: we covered this in earlier issues of The MagPi a couple of times however it involves getting ones head around the internals of the USB protocol and while learning about USB Vendor IDs is "fun" in one way it certainly isn't conducive to encouraging people new to robotics into the hobby.

Ben also tells me that the age range of the arm is "officially...11+ but with some parental supervision it can be built by as young as 8 or 9 without too many problems." Producing a product that is interesting and accessible to age groups from primary to adult is a great achievement: "We believe in helping children to have fun whilst learning about technology and the MeArm Pi is completely designed around that goal". Superb.

It seems that MeArm Pi is not the only product that Mime are looking at for the future too:

Ben: "This is the first new product from Mime Industries since we formed the company. We’re going to be taking another look at updates to Mirobot as well as rolling the improvements to the MeArm mechanical design over to the other versions. We’ve got lots of ideas for new products but you’ll have to stay tuned for those!"

And stay tuned I most definitely shall.

MeArm Pi, available for another 6 days on Kickstarter.

MeArm Pi

PaPiRus ePaper HAT: what about the software?

In my previous post I mentioned that I was still getting the software for PaPiRus installed. Well, success and all is well. Here are a few screenshots of the 2.7” screen. Note as before that this is a pre-production model and I’ve been told that the screen I am using is an earlier version than what will be shipped to backers.

PaPiRus is available for three more days on Kickstarter.




PaPiRus ePaPer HAT hardware preview

Aaron of Pi Supply has very kindly posted me a PaPiRus ePaper HAT preview unit. This is a work in progress and Aaron was open that the software side of things still needs work. Fair enough, I’m happy with that: after all in a pre-production unit one does not expect perfection. I have previously covered the Kickstarter and the advantages of using an ePaper display. Today we will be looking at the hardware.


The unit was supplied pretty much ready to go with the three sizes of display (1.44”, 2.0” and 2.7”) along with a coin battery and v1.4 of the HAT itself. The first thing to note, and I owe Aaron and team a beer for this design decision, is that the ribbon connector between display and board uses a click up, insert, click down affair, as opposed to pull, slot in, push that is used on the Raspberry Pi Camera module. This makes inserting the ribbon cable easier and the connection notably more secure when clicked back into place.

The rest of the HAT is similarly well thought out (there is even a slot in place to allow the camera ribbon cable to pass through). As with all HATs this will be equally in place on a B+, B v2 or A+ Pi. The combination of Raspberry Pi A+, PaPiRus and 2.7” screen all in a tasty case mounted on a wall displaying data of one kind or another is very appealing as this will be a very compact, very energy efficient solution for a multitude of projects. I can even see this combination being used as an in-car display screen connected to a car’s OBD port for the same reasons.

The upper side of PaPiRUS is mostly empty, giving you a flat platform to rest your chosen screen upon. Along the top are four tactile buttons which will make interacting with the Raspberry Pi and PaPiRus straightforward.


On the reverse we find lots of little components, all pre-soldered with precision. This isn’t some DIY rough-and-ready solution, but a professional product. It re-confirms what I’ve known about Pi Supply for a while: this is a professional outfit producing products that us consumers can rely upon.


For those who like technical details I got my magnifying glass out and noted the following (obviously this is all subject to change, this being a pre-production board):

IC1 (directly above the edge-mounted ribbon connector) is flash memory from Winbond, part number W25Q32FV. This gives me a clue that the firmware could be updated in the future as needed.
IC2 (up-left from the battery) is a NXP 8523T which the datasheet tells me is a real-time clock and calendar
IC3 (above IC2) is a NXP LM75BD which is a digital temperature sensor and thermal watchdog
To the left of IC4 (below the battery) we have a B6MY which Google tells me may be a folding pocket knife. I think my Google Ninja skills failed me at this point.

The hole for the reset pin is present on v1.4 of the board (below-left from the battery) and with less than £3k to go at the time of writing we’re sure to unlock this stretch goal.

UPDATED: Most intriguing of all on the v1.4 design is the inclusion of a second ribbon cable connector at CN4 (above battery). Aaron pointed out what I had completely failed to notice: that this is a GPIO breakout (see the last photo on the Kickstarter page).

The board is rock-solid, with no loose chippery to be found anywhere. PaPiRus is on Kickstarter for 5 more days and looks set to be an excellent way to add an ePaper display to your Raspberry Pi.


Pi PoE HAT Kickstarter

Like all computers the Raspberry Pi can quickly become a spaghetti junction of cables, cables and more cables. And cables have a mind of their own and are evil, entwining themselves into knots the moment your back is turned. It is into this plethora of power, USB, ethernet and HDMI connections that Pi Supply comes to the rescue with a rather clever Power Over Ethernet (PoE) offering.

PoE is one of those it-does-exactly-what-it-says-on-the-tin offerings: providing power to the computer via an ethernet connection and hence meaning you can wave goodbye to a cable. It is quite a clever idea really: ethernet requires power, your computer requires power, why not combine the two? The Pi PoE HAT gives you just this, throwing in a handy programmable button as well. Plus, the GPIO pins remain available for further connections. Note though that you do need a PoE compatible switch or injector to provide the power though.

Last night when I was previewing the Kickstarter a thought occurred: why not combine PoE with PowerLine? Now THAT is a tasty idea: use ethernet for power and your house’s power circuit for ethernet. Googling shows me there are various options for this and I’ll definitely have to investigate this some more.

There are many valid cases for PoE and the Kickstarter gives some ideas about how this can be used.

PaPiRus ePaper HAT Kickstarter

Chatting with Aaron of Pi Supply recently I became aware that he was about to put something live on Kickstarter that is really exciting. I promised to keep quiet until launch day despite constantly wanting to shout “This is AWESOME!” from the roof tops.

Pi Supply are seeking funding for a superb ePaper / eInk HAT on Kickstarter called PaPiRus. It’s an absolutely genius design with four buttons mounted along one edge and up to a 2.7” ePaper display. Why is this “AWESOME” you may ask? Well, ePaper displays only require power when the image is updated. It is this fantastic property that gives the Amazon Kindle such excellent battery life in the “weeks” not “hours” category. Combined with the low power Raspberry Pi and you have something that’s cheap as chips to run. This is even more so with the Raspberry Pi A+. Alex Eames of did an excellent write-up of the respective Pi’s power usage.

Now, ePaper is not going to be for everyone. If you require colour, or fast screen updates in the ms range then a traditional LED/LCD screen will be more to your taste. But for status displays, Twitter feeds and the like, and especially if you need to run off batteries (this HAT will work stacked with Pi Supply’s Pi Juice) you just can’t beat ePaper. Tim Cox once repurposed a Nook eReader as an ePaper display for his Pi, but obviously this requires a fair bit of effort to get working. The beauty of the Raspberry Pi HATs is that they are pretty much plug and play, hence PaPiRus gets a massive thumbs up.

What’s more, PaPiRus is being made by Pi Supply who have a history of creating superb add-ons for the Raspberry Pi (and PiJuice of course) that are delivered as promised. I’ve no qualms at all about entrusting my money to Pi Supply for one of their projects. Pi Supply just hit the £5k fully funded mark with 30 days to go. This is clearly a project you can have confidence in.

Head on over to Kickstarter to back PaPiRus.


A clock for your Pi

A Kickstarter is currently running for PiMuxClock. It is a great self-solder or pre-assembled (depending on what one pledges) kit that gives you a 4-digit clock, a header to attach a real-time clock module (not essential to use the kit), temperature sensor and a few other bits and pieces too.

What is absolutely fantastic is the price, which at £7 for the early bird (and £8-£10 for the not-so--early or the I-want-more-features pledger) represents stunning value for money. It is low priced kits like these that actively get people into soldering. Looking at the parts list this is a straightforward kit that has a definite pleasing end result and I imagine would be great as a supervised soldering project for kids.


PiJuice - a brilliant portable power solution

I’ve been looking for a portable, battery powered, solution for my Raspberry Pi for a while now. There are some good offerings (and some less-so) on the market but none have really ticked all the boxes for me: compact, slimline, capable of automatically not frying the Pi when I also want to run from mains power, and with a passthrough GPIO connector (stackable with other goodies). Effectively I’m looking for something dinky that will fit on a Zumo Robot.

Today, a great email appeared in my inbox from PiSupply describing PiJuice, a portable battery solution that ticks those boxes and more besides. It looks (to use my favourite word) AWESOME. The slimline design and HAT form factor is very in keeping with producing dinky robots. I’m liking what I see here.

Watching the video on Kickstarter I can see the team behind PiJuice really thought long and hard about how to produce the ideal battery for the Raspberry Pi. For example, at one reward level they offer a solar cell for charging in remote locations. This is a really tempting proposition for so many Raspberry Pi projects I read about in the developing world.

But, it doesn’t stop there. The Kickstarter page and video describes tutorials that they will be producing covering interesting things one can do with PiJuice, including a portable point and shoot camera which looks great.

The funding on this project appears to be going crazy: in the first day they have already exceeded their target by ~£2000 (and climbing - every time I refresh more have backed it). I’ve backed it straight away.

Kudos to the team behind PiJuice for producing what looks to be one of the most useful and interesting add-on boards for the Raspberry Pi.


Charlieplexing Kickstarter (with a Christmas Tree)

Over on Kickstarter I have just come across an interesting GPIO Christmas Tree project. Now, before you wonder why the world needs yet another GPIO Christmas tree, this one is a bit different as it uses something called Charlieplexing.

I’ll be honest and say I’d never heard of Charlieplexing before this point (multiplexing, yes). It’s a really interesting technique for getting more functionality out of a smaller number of GPIO pins. Andrew Gale, who is running the Kickstarter campaign, has an interesting video on how this technique works up on YouTube.

Andrew’s pocketmoneytronics is building up a great set of low cost interesting Raspberry Pi boards. Good stuff.

The MagPi Kickstarter campaign

The MagPi magazine is now running a Kickstarter project with the aim of getting printed copies of all 8 issues in volume 1, plus a special binder to hold them all, into your hands. From the Kickstarter page:

Bring The MagPi magazine, the best and only magazine for the Raspberry Pi enthusiast, from the digital realm into the physical realm.

I’ve posted a fair bit on here about The MagPi, in part because I write articles for the magazine, but also because I genuinely believe it is a superb read with excellent well thought out articles. I’ve learnt lots by reading each issue and have seen the team grow in strength and capability over the months. This means that each issue is a valuable resource to help anyone of any experience level to get more from their Raspberry Pi.

The current issue shows just how detailed the articles are by presenting a foolproof way to catch Father Christmas (oh ok then... “Santa”) later this month. Now in my eyes that alone is worth contributing to the Kickstarter project (anyone remember the Red Dwarf episode Backwards?)

Please do support the Kickstarter project.