With LAMM recently taking on the task of revitalising and preparing laptops for schools in the local area, one of the first things we are doing — before anything else — is securely wiping all data on them. This lengthy process writes random data (using the same techniques as the US’ Department of Defence) across the whole disk, ensuring that nothing can be recovered from storage, and giving donors the piece of mind that none of their data will be accessed.
To accomplish this, we’re using a tool called DBAN which specialises in securely erasing hard disks. Normally, you’d write this to a USB drive, plug it in to the ‘destructee’ computer, and boot off of it, but I didn’t really fancy buying 25 USB sticks for the current stock of laptops in the Space. So, a better solution was needed…
Many Laptops at the Same Time
Thankfully, I’d brought my laptop with me, which I could run a PXE netboot server on – this would allow any devices connected to the same network to boot from anything I liked, as long as I had it on my laptop. I went about setting up a PXE server (configured as a proxyDHCP server pointing to a DBAN boot image on a TFTP server), tested it out, and was ready to roll. This solution meant that no USB drives were needed at all. All that I’d have to do is plug a to-wipe laptop into ethernet, and turn it on. (Perhaps also configure the boot options to use PXE.)
PXE booting
We’d been (and still are being) given quite a range of laptops at this point – everything from this extremely pink laptop:
Pretty snazzy
…to this teeny tiny little machine:
But thanks to how widely adopted PXE is, all the laptops (bar 1, boot password) were as simple as ‘plug in, power on, data gone’. The first stage of a thorough process to get these laptops to in-need school pupils.
The boot server running on the host laptop (and an iPad for music of course):
PXE/TFTP/proxyDHCP server running under Windows 10 under Parallels on a MacBook connected to the network over WiFi. Luckily the boot image is only 17MB.
There were laptops everywhere, from on top of the laser cutter:
To on top of the fridge:
There were even a few that had decided to sit around and have a meeting.
Not very socially distanced… Hopefully they don’t get a virus.
In the end, around 20 laptops were wiped that day. They’re good and ready for the next stage of cleaning up, and then installing an operating system to. Check LAMM for updates!
It doesn’t need us to say that we are all living in rather exceptional times. Recently LAMM was approached by a local school, via a governor, to give help to some of the pupils.
The Government has an initiative whereby Secondary Years pupils can apply for a laptop to work from home and maintain some connection to their education. However, there is very limited provision for Primary Years children.
There are many children in the local area, and nationally, below year 7 who are being left behind in these times. We have started an initiative to collect unwanted digital devices (Laptops and Tablets) that have the ability to connect these children to their schools. We have gained the support of a number of people.
In the past few days the initiative has started to take hold and Kay (a director at LAMM) will be appearing on the local Heart radio. Local businesses and Erica Lewis (leader of the Council) has given vocal support to our efforts.
We have a drop off point at the Gatehouse in White Cross (White Cross Industrial Estate, South Road, Lancaster, LA1 4XQ) and we can also do a doorstep collection of your device if that is required (especially for those of you who are vulnerable or shielding. Please note we can only pick up from LA1, LA2, LA3, LA4, LA5, LA6 areas.
We are taking any machines that can be made to use a modern browser which is the requirement needed to run the software that connects children to their teachers. We will even take machines that need some repair as we have a growing number of parts and members willing to volunteer their time. Note that because we are volunteers we may take slightly longer than expected to respond to any communication.
All machines will have their data wiped using a secure wiping program before the system has a new operating system installed ensuring your data is safe. If you can donate then please do so. We are also interested in any parts such as RAM, hard drives and essentially laptop chargers. These can help revitalise an old machine by adding more physical memory of a bigger/faster disk and by having a safe power supply.
The first of the laptops are being prepared this week for delivery to school next week. Please note that we are not taking desktop machines at this time as they are too cumbersome and need a separate devices to be functional.
If you can donate please fill out the form here. We will keep any information you submit safe and will ensure any personal details are only used by directors or those tasked with collecting machines. All personal data will be deleted after the minimum legal period required by a business to hold data or on request.
Today we are officially opening the LAMM Space at White Cross for use by members. The Space has been closed during the Covid pandemic for the safety of everyone but we have now been able to procure supplies and formulate a procedure for the safe use of the community workshop.
At this time the Space will only be open to paying members. We will not be opening for public open days for the foreseeable future. Once the crisis is fully abated we will publish a schedule for public opening times.
There are a few rules for the use of the space. All members must follow these for the safety of everyone:
Using the Space
Only one person in the Space at any time. Please make sure to announce in the LAMM Telegram channel if you are in the Space and when you leave. Please check the channel before going to the Space to ensure it is free. If you live in the same house as another member then it is safe for you to both be there at the same time.
Use the sanitation station provided by White Cross and follow all guidelines for public spaces.
Gloves, masks, wipes, hand sanitiser and surface sprays are available in the Space. Please make sure to use protective covering to reduce the chances of infection and remember to dispose of them waste in the bins provided. Please make sure to wipe down all equipment with the cleaning spray provided even if you are wearing a mask and gloves.
Please respect other members property. Please clean all tools and equipment away after yourself.
Do not remove any cleaning or protective equipment from the Space for your own use without permission from the Directors.
Please let us know if any replacement cleaning or protective equipment is needed.
If you show symptoms…
Do not come to the Space if you have had any symptoms in the last 14 days.
Do not come into the Space if anyone you live with has, or has had, symptoms in the last 14 days.
If you show symptoms after visiting the Space please let the Directors know immediately and let us know when you were at the Space and what equipment you used.
Keep monitoring the Telegram channel for any up-to-date information. Also to request times and to communicate with other members.
We want you all to have a safe return to the community workshop. We apologise that there are measures in place and rather dictatorial rules to follow about usage.
A big thanks has to go to Kay Kempers who has made the Space safe for us all to visit and has secured all supplies and made all the signs.
In the last few weeks a few different conversations have focused on how our rules for members work, as we only have the four, in regards to all the edge cases. Let me broadly refresh you on the rules for members:
0. Don’t be on Fire
1. Follow the Code of Conduct
2. Protection of underage members
3. Don’t do anything stupid so we have to make up new rules.
I personally don’t want a lot of rules, however that means that we don’t have absolute guidance on some matters such as:
Animals in the Space
Laser and other machinery usage
Item Costs
Snack Space
Tidying
My proposal then is to have a set of guidelines for members on this website, under a new section called, conveniently, Guidelines. I would like any guideline to be published in a format that is easy to find, accessible and able to be amended and altered. These are not set in stone, they are guides for sharing and co-operation.
I would also like to be able to vote on them, and that is what I will propose we do at AGM’s and other meetings, and via member polls. I will be suggesting this is the practice we follow at the AGM in 2019 and I will be asking for a vote on this and a couple of guidelines at that time.
Sunday was the ‘Make My Day’ festival located on Morecambe Promenade, set up by The Exchange, a maker group operating out of Morecambe. LAMM had been given a stall at the show to display our own set of interests and skills, consisting of 3D printed objects, a set of computers to dismantle and the incredibly popular slime production.
Shaded under a gazebo Elly, Bill, Dave and Andrew welcomed visitors to the stall to educate them on the wonders of making things. On one side was the computer area, offering a mix between ‘how its made’ and ‘scrap heap challenge’. Dave supervised all age ranges to take apart the many defunct laptops that had been donated to us. It was really great to see the excitement that taking things apart inspires, stimulating the curiousity that is the foundation of all makers. Asking that always important question ‘how does it work?’
The main attraction of the day was undoutedly the slime factory. Where Elly and Bill aided the crowd in turning PVA glue, poster paint, bi carb and shaving foam into a gloopy, slimey mess. The audible astonishment when the activating contact solution was added to the mixture was really something to behold. A special mentinon to both of them for the hard work they put into doing this as they rarely had a moment to themselves.
The festival was excellently run, with a great assortment of stalls and attractions offering so many different activities for participants to enjoy. A lovely lunch helped the volunteers to keep going and the weather made it a really ideal day.
A great thanks to everyone who volunteered and the organizers of the event. These attractions are so important to keep the spirit of creating and community alive. Knowing the drive to create is what got us as a society to where we are today, events like this ensure the next generation will keep the tradition alive.
This Saturday 17th March 2018 is our usual Open Day and it is also World Create Day along with Hackaday.io.
There are over 100 spaces participating this year! Here is everything you need to know to make #WorldCreateDay the most amazing world wide event makers have ever seen!
Here is the link to our event on Hackaday.io, so maybe sign up if you are coming along: https://hackaday.io/event/78299-wcd-shadowcat-systems
Use the hashtag #WorldCreateDay and Tweet about our event!
Take pictures & tweet them with the hashtag #WorldCreateDay, and encourage people to do the same. Make sure to ask for permission to use them in images shared online! The more you post the more likely you will be featured on Hackaday.com!
Follow the Tweet wall linked below to see all the creation happening world wide! Everyone at our event can follow along (and join the buzz themselves) if we put it on a screen somewhere.
The Hackaday Prize is a global competition for socially impactful hardware projects. There are over $200k in giveaways this year, and everyone expert to newbie is encouraged to participate!
This is a fun way for our community members to share what we’ve been working on. So let’s tweet pictures of it with #WorldCreateDay and encourage people to submit their project to The Prize!
In the third post of the month/night after a cabinet and a Google hat I wanted to quickly talk about Prusa Control. Prusa Control, for the uninitiated, is a cut down version of the, very useful and powerful, Slic3r software for the Prusa printers.
Prusa love Slic3r and there is no reason to doubt it. They build a custom profile for the software and make sure it is shipped and linked across their brand. however they note that it can be over-whelming for beginners. That’s where Prusa Control comes in.
Prusa Control is aimed at ease and speed and with just settings for the Prusa 3D printers and there is something lovely about that. I have installed the beta and used it for a first print in my new cabinet.
It worked really well.
In fact I would say close to perfect. I printed with a brim and with loose settings (.2 at 15% infil for speed and ease) and I got a near perfect print with good bridging and detail and a wonderful layer height that is regular with no breaks or interrupts. The brim was light and they clearly had taken care to make sure it was a well printed but easy to remove printing support.
So for new users and for experienced users wanting to cut out the interface and get straight to the printing then it is worthwhile having Prusa Control next to Slic3r in your toolkit.
I also liked how smooth the layer height display worked after generating which is very quick and efficient.
A very clean and easy to understand interface greets you on opening, seriously the controls on the side are all you have to deal with, this is minimal and almost perfect
Easy to understand layer height control
One of the prettiest and nicely printed brims I have ever worked with
The second blog post of September, and actually the second of this evening, concerns a recent build of an electronic item I did with my son (#1Son, Ben).
I managed to pick up the Google AIY Hat for the Raspberry Pi with MagPi for a very affordable £5 and Ben and I decided to build it together and to video it for our YouTube channel.
The build was complemented by printing a box from a design on Thingiverse instead of using the cardboard one. Rather than say too much more I have copied the video link* (and you can also play the video below) so you can view it without leaving this page.
If you like the video please give us a thumbs up, and if you have constructive criticism then please feel free to comment.**
As always I wouldn’t be doing this if I didn’t have so much support and encouragement from my LAMM peeps, thanks guys, and especially, as always, to TBSliver who is always there with advice and support. He gets a big shout out and lots of free dinners at my house ;P.
** A part of me says that if you have negative or destructive personal criticism then I should probably know what it is or alternatively you can write it on a piece of paper and place it under a rock on Mars for me to find when I decide to be a Spaceman in some alternate reality :). I really would like to hear any good criticism, positive or negative that helps me in the future.***
*** Obviously, and I shouldn’t need to say this but a small part of me realises this goes to YT and Twitter as well so has to add this caveat, if you have any criticism of Ben then do the decent thing and keep it to yourself, children have far more impressionable egos :P.
For a while now, I have been trying to make a dry box for storing 3D printer filament, having had problems with a reel of ASA filament becoming damp and the prints made from it coming out pitted and fragile. The first idea I tried was to use silica crystal cat litter as a dessicant in a sealed box. I bought a transparent storage box with a rubber seal and a packet of silica cat litter, as well as a cheap digital hygrometer / thermometer. Then I burned some holes in the lid of a plastic fast food tray with a heated skewer, and put the cat litter in the tray. Finally I put the tray, the hygrometer and the filament into the storage box and sealed the lid.
I left the cat litter in the box for a full day, and the humidity reading actually increased slightly from 55% Relative Humidity (RH) to 59% RH. This was at a nearly constant temperature varying from 24 °C to 23.7°C. The increase was within the error range of the meter but not the significant drop I had been hoping for.
The next thing I tried was to crush the crystals using the somewhat crude method of wrapping them in a strong piece of cloth and bashing them with the end of a brick, to see if this would increase the surface area of the crystals and make them absorb water better. This didn’t work so well as silica crystals are quite hard, and it also didn’t make them any better at drying the air in the box.
I suspect that the reason the cat litter didn’t work is that even though silica does absorb water, the granules you get in the sachets that come with electronic devices are prepared in a way that makes them highly porous and able to absorb atmospheric moisture, whereas the silica that is used as cat litter is designed to absorb liquid water so they make it out of solid crystals.
At this point I did a bit of research online and found this web page about drying mushrooms. It has a pretty good summary of the three main substances used as dessicants, how effective they are, and how to use them. In order of increasing effectiveness, they are silica gel, which will bring the humidity down to about 40% RH, calcium chloride, which is what is found in home dehumidifiers and can bring the humidity down to below 25% RH, and calcium sulphate, which is the strongest of the three and according to that page can lower the humidity to a few percent RH.
As it says on that page, calcium sulphate is the same chemical substance as plaster of Paris. This is a substance which attracts water strongly into its crystal structure, and can come in several forms depending on how much water it has absorbed: hydrated (fully saturated with water), hemi-hydrated (partly saturated), and anhydrated (no water at all). Plaster of Paris is the hemi-hydrated form and can be bought quite cheaply from craft shops.
The simplest way to make powdered plaster of Paris into a dessicant would be just to heat it in an oven to drive the water out of it, let it cool in a sealed heatproof container, and then put it into the dry box. This would probably work okay, but it would have the problem that air wouldn’t be able to percolate through the powder easily so it might take a long time to dry the air in the box.
I decided instead to try to make it into granules, thinking that they might absorb the water vapour better. The rest of this post describes how I did this.
Some of the equipment I used to make the granules.
The photo above shows some of the equipment I used to make the granules – two non stick baking trays, a bag of plaster of Paris, a mixing bowl and metal spoon, and a kitchen weighing scale. I also ended up using a couple of large glass jars, some rubber gloves, two plastic bags, a piece of heavy cloth about 40 cm square, some string, a pint glass of water, and a brick.
The first thing to do was to measure out enough plaster to fill the baking trays in a thin layer. You may want to wear rubber gloves for this as plaster is slightly irritant. I did this by just spreading it out in the trays to what looked like a reasonable depth to be able to break it easily once it had set.
Then I put the mixing bowl on the scales, zeroed them, poured the plaster into the bowl and wrote down the weight – 442 g.
Weighing the plaster of Paris
You make up plaster by mixing it with water in a ratio of 100 : 69 by weight. This makes 305 g of water, which makes a total of 747 g in the bowl. I then made a bit of a hole in the middle of the plaster and poured water in until the weight was (about) 747 g. Then I mixed it with the spoon until it was smooth, and poured it into the two trays in roughly equal amounts.
Liquid plaster in baking trays
I then allowed this to dry for a while (the instructions on the plaster say 6 – 10 minutes). The next thing was to take the plaster out of the trays and break it into granules.
To do this, I first put the trays inside a large plastic bag and turned out the sheets of plaster. These came out quite easily.
Turning the plaster out of the trays
Having done that, I then put the bag inside another bag, broke up the plaster sheets a little bit by hand and then wrapped the bags inside the cloth square with a piece of string.
Plaster fragments inside bags
Plaster and bags wrapped in cloth
The next thing was to bash the bag with the end of a brick until it seemed like the plaster sheets were all broken up. Then I took the newly broken granules out of the bag, laid them out in the baking trays, and baked them in the oven at 230°C for two hours.
Plaster granules ready for baking
I left the trays on the hob for a couple of minutes to cool down a little, then poured the granules into the large glass jars to cool properly.
Plaster granules cooling in jar
Once they were cool, I put them into the plastic tray with the holes in the lid and sealed this in the storage box with the hygrometer reading visible through the plastic sides.
Plaster granules, hygrometer and filament spools inside the dry box
The box sealed with the hygrometer reading showing
Finally it was time to see if the granules were going to work. I wrote down the time and relative humidity for the next few hours, and watched the humidity fall from 62 % RH at 16:42 to 27 % RH at 23:04. It fell quite fast at first, going down to 38% by 18:03, and then slower after that. Whether it will get all the way down to the level of a few percent that the web page I referred to above says you can acheive using calcium sulphate, I’m not sure yet, but I’m pretty pleased with this result, as it is below the level that is supposed to be acheivable using silica gel.
One test I would like to do is to open the box again in a day or two, let the air mix, and then see if the humidity drops as fast the second time, to get an idea of how much drying capacity this amount of dessicant has. If I get around to this I’ll post an update in a comment.
On the 17th of June from 12pm to 5pm we are organising a day of demos and talks on the subject of ‘3D design for 3D printing’. There will be several talks and demonstrations on the subject of how to use 3D design software to produce physical objects for manufacture, whether on a 3D printer, laser cutter, or CNC milling machine. If you are curious about 3D printing and other computer based manufacture techniques but don’t know where to start, or if you have experience but would like to share skills and ideas with others, this could be the event for you. All ages welcome but under 16s must be accompanied by an adult.
The talks / demos will be:
Tom Bloor – Introduction to Fusion360.
Ian Norton – Modelling in OpenSCAD.
Andrew Baxter – 3 ways to model a real object in FreeCAD.
— break —
Dave Leack – 3D Printing with Blender: Common errors and how to fix them.
Ian Jackson – Modelling in Vectric Aspire.
The talks will last between 30 to 40 minutes, with a 20 minute break in the middle.
If you would like to help publicise this event, please download and print out this poster, and put it up wherever you think people might be interested.
