Tuesday, 16 August 2016

Variable voltage DC power supply



Finished making a little case (well a front and a back!) for this variable power supply that I had worked out and wired up a while back and then had on the (enormous) to do pile! I finally got round to drawing a bit of cad and I cnc routed these panels. The panels are just 4mm mdf with a bit of spraypaint to finish them. The gubbins comprises of a very cheap variable voltage dc-dc board which is a lm2596. They come with a small ceramic pot on the board to vary the voltage but I've replaced that eventually with a 10 turn pot to give me the resolution I need to set the voltage to 2 decimal places! (I say eventually, in testing I used an ordinary pot which proved the concept but was difficult to even hit a value to the nearest volt!!)
 These variable buck dc-dc boards take a voltage input of anything between 4v and 35v and will output a voltage range between 1.23-30v, they seem pretty stable. The display is a 3 digit voltage display like THIS, It is important you get one that is listed as having 3 wires, namely then it takes its power supply from the input voltage and has a third wire connected to measure the output voltage.. there are some that only have 2 wires that just connect across the output voltage which means when the voltage drops below around 3.3v.... they turn off! The 3 wire ones happy measure down to the minimum values. (note neither of the links are traders I've used.. rather just to show the stuff!)

The back panel has the inputs on the right and the outputs on the left all on 4mm banana jacks... I love cnc routing.. it makes you able to get these things really precise.. If I had had to drill those holes manually I would have designed it with more space between them making the entire thing bigger!

Anyway.... nice to finish one thing off the pile!

Thursday, 11 August 2016

A trip to CERN, Science, Innovation and Open Source.


So.. Been on holiday and toured around Europe taking in 9 countries and doing about 2600 miles over 3 weeks.. lovely! One highlight that is geeky enough to warrant a blogpost is I got a quick trip in to CERN just north of Geneva. As I had the kids with me the 4 hour tour was out of the question but the 2 visitors centres (mikrocosmos and the Innovation Sphere) where definitely do able... and they were brilliant. One of my best parts was chatting to an amazing guide ( a particle physicist who did shifts in the visitors centre and was FULL of passion) and in particular we talked about CERN and open source, prompted by me mentioning using Kicad which CERN have used and developed and shared back into the community, he spoke at length about numerous complex high end software/systems that CERN has done this with and affirmed in me that across the vast majority of the huge complex that is CERN and LHC and ALICE and  ATLAS and CMS an open source attitude prevailed. It was reaffirmed later in the trip wen you stand in front of a console that shows in realtime the data flow mapped over the world that is CONSTANTLY being streamed to hundreds of recipients around the world. Inspiring... I used to alway say that the ISS is mankinds greatest technological achievement... but darn... CERN is a close call...

Here are many pictures!....

Cloud chamber (refrigerated alcohol vapours) that captured and rendered visible particles passing through it.. cosmis radiation and muons etc! Kids loved this!


As well as great renderred and interactive diplay activities lots of real time data was on screen from the LHC.

All cryo pumps green!

Great virtual tour where you could steer yourself flowing through the particle accelerator and the 3 main experiments en route.. Photo's don't do it justice!


More live data

Live power use... blimey!


Outside there was a selection of pieces of kit... such amazing engineering and machining in these, beautiful. The above was a big RF chamber

The Gargamelle bubble chamber... revealed to humanity some neutrino secrets.



An amazing piston... about 2 meters in diameter it apparently pumped ovder 300million timnes in its active service at a rate of 3 revs per minute... each stroke delivering 350 tonnes of pressure! 

Ignore the dodgy dude in shorts (me) this sculpture had cast into it details of all major scientific and in particular physics milestones... inspiring.

The science and innovation sphere runs an immersive mapped projection show on multiple screens and surfaces in various languages... it was awesome and the kids really enjoyed the space. 

My daughter was really engrossed in this sphere... love this picture... the seeds of technology.


Thursday, 14 July 2016

Super Cheap Digital Read Out (DRO)







So, a DRO for machine tools (lathes, milling machines etc) is a digital read out that tells you the position of or how far a given axis has travelled. Obviously this useful if you want to make a part or a cut into a component to an accurate size, the trouble is... they can be very expensive! Even a hobby level DRO setup for say a milling machine can run to hundreds of pounds.  One common workaround (apart from using the engraved hand wheels) is to use a Dial Indicator set up to indicate how far a given axis has moved and indeed I've used that technique a lot. (it's a nice technique as it automatically cancels any error due to backlash as it isn't linked to the lead screw and always tells you the exact position of the axis). Still dial indicators and requisite holders/clamps can cost a few quid and can be awkward to get into a good position etc... so when I saw this hack to convert a tyre tread gauge into a micro DRO... I knew it was for me..

So these digital tyre tread indicators are super cheap... I paid £3.99 for one and could have spent less if I was prepared to wait for one to be delivered from the far east. They are essentially a short travel version of the cheap digital callipers that are widely available ( and indeed have the output slot that people have exploited to create data logging calliper )..  So the modification consists of a couple of different things... firstly you need to reduce the drag on the calliper slider which is created by a small steel slip inside the device.. this is for when you measure a tyre tread you can position the indicator then remove it from the tyre to read the result and the slight friction on the slider keeps it in position. For the DRO hack we need it to be as free to move as possible. Once this is removed I turned a small collar for the end of the probe from some Delrin which was drilled to fit the probe end snugly and the other end drilled to house a cheap but powerful 3mm diameter neodymium magnet



For the next part I whipped up a quick drawing to be able to CNC rout a plate for the base that would house the larger magnets. I made the toolpaths tight to the 8mm diameter of the magnet so that they were an interference fit and required pressing in on my small arbour press (also for added security I put a blob of superglue under each magnet). I then glued the magnet base to the base of the unit and hey presto... a portable quick fit DRO!



It works great, I am really pleased with it and will probably for the price make a couple more.. Its also great that the 8mm magnets are enough to hold the device firmly even if only 2 magnets are attached to whatever it's clipped too. The zero function of the device means that even though it only has a small throw (27mm) it is easy to sequentially move the DRO and zero and keep a running count of position over a longer length. 


Saturday, 9 July 2016

Another quick make, Ball and socket joints!


In amongst a busy week I managed to fit a little make in! I was inspired to make these by my twitter buddy Rob Ives ... for the uninitiated Rob is a master maker and what he can't engineer out of paper doesn't leave much! Check out his website for some great stuff and projects to download.. https://robives.com/ 

So anyway.. these ball and socket joints are made from some cheap 12mm nylon beads I got on ebay which I drilled and tapped (awkwardly... the nylon tends to melt when drilling making it tricky) to take some M4 bar.. The wooden sockets are cut on my CNC with the holes for the beads being 9mm diameter. A bit of tension on the bolts and the result is a grippy yet positionable joint. I then turned up a small 8mm lug and tapped it to M4 as well and attached a crocodile clip (with a blob of epoxy) to the other end. Hey presto... another accessory for my ever growing accessory station! 



Tuesday, 5 July 2016

Quick make... baseplate for accessory stand





Stalwart readers of this blog (a very elite club!) may know that I have an ongoing project that started off as some Dial Gauge accessories which then expanded to include a tapping stand and indeed on my last post about making the PocketQube chassis I posted a photo of me using it to tap some small holes. It worked great but made me wish that instead of just a big lump of (recycled in my foundry) aluminium as a base I had something that I could put my precision vice on. So to the scrap pile! Within my hoard I had a base off an old black and decker drill press stand (the type you insert a hand power drill into a collar). Despite being a pretty poor casting that has a few marks from some abusive drilling with a few file strokes the base sat level on a level surface and cleaned up well. A lick of grey enamel paint smartened it up a bit as well.


To attach my DTI/tapping stuff I turned a bit of mild steel to the diameter of the old drill column and then drilled and tapped an M6 hole into it. Into this I inserted a short piece of M6 threaded rod with a bit of thread locker to keep it in. It's worked really well. Next on the list is I need to mill some flats onto the piece that screws onto this base and has the clamp slits that hold the uprights and make a spanner so I can nip it up a bit more. 
The obligatory before pic!

Sunday, 26 June 2016

Liverpool Makefest 2016




So just a quick small picture dump after a great day volunteer Crewing at Liverpool MakeFest.. a great event in a great venue,  Liverpool Central Library,  with a good vibe and lots and lots of people! Perfect...

This pic is about 15mins after opening.. filling up nicely.. got lots more packed than this!

Nice crew badges (gagAAARGGH blogger still doesn't rotate images!)

Ragworm posse showing their wares..

Nice little activity showing where people were from... (a few more N Waleian tags appeared by the end of the day)

I bought some of these! AR pictures with a free AR game app.. the kids loved em! By the wonderful Midnight Polygon

Can't escape Darth...


 These guys are GREAT, they call themselves "we like to make stuff" and I've met them a few times now first time at Makers at MEX they have enthusiasm and humour and make anyone approaching their stall welcome .... proper makers. Spot on.


Friday, 10 June 2016

EMPQ Pocketqube engineering model


I've been working hard on an engineering model for Paul Kocyla for our EMdrive pocketqube project. It's been a good learning curve with lots of realisations for the next iteration! It has no skeletonising as we want it to be as rad hard and as RF dampened as possible. 

Underside showing the cutaways, currently the bolts are oversize and stacked with washers as I didn't quite have the correct size and the PQ baseplate will be mounted using the same holes.




Just a few in production photos.. marking out above and the blanks for the internal brackets




Lots of tapping of the M2 holes on the 6mm internal brackets, my home made tapping stand has earn't its keep! Likewise the little precision vice which is an excellent purchase.

Milling the 2mm wall square tube to size on my trusty Sieg sx2 plus. 

So.. off it goes in the post tomorrow to Germany. :)