Category Archives: Uncategorized

Open Day this Saturday, April 14th.

 

Crochet CRAFT LogoThe next hackSaturday will be from 10:00 until 16:00 on Saturday the 14th of April

So why not pop down and say hello. There will be members there to show you around or chat about the space and what people do here.

Want to know how to find us? Click here

For more details about our open nights, see the wiki.

Curious about what to bring?

All you need is yourself, enthusiasm and curiosity. Feel free to bring a project, things to make, things to do, things you want help with, or things you just can’t find time to do elsewhere.

What does the hackspace have to offer?

You’ll be free to use whatever tools and facilities you want, subject to the necessary training and/or supervision. Non-members will be expected to contribute towards hardware, electronic components etc (members get all this stuff for free!) if it’s more than a few bits and pieces. We have a fast Internet connection sponsored by Andrews & Arnold which you’re welcome to use. And a tuckshop!

 

Questions?

Please contact us using any of the methods below!

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hackSaturday This Weekend!

 

 

 

The next hackSaturday will be from 10:00 until 16:00 on Saturday the 24th of February

Wednesdays have been Open Nights since version 1.0 of York Hackspace, way back when we used to meet in the Black Swan. However, we understand that weeknights aren’t the best time for everyone to visit the space.

We are therefore pleased to announce that we are starting up hackSaturdays: different day, different time, but the same original recipe as the Wednesday Open Evenings.

Want to know how to find us? Click here

For more details about our open nights, see the wiki.

Curious about what to bring?

All you need is yourself, enthusiasm and curiosity. Feel free to bring a project, things to make, things to do, things you want help with, or things you just can’t find time to do elsewhere.

What does the hackspace have to offer?

You’ll be free to use whatever tools and facilities you want, subject to the necessary training and/or supervision. Non-members will be expected to contribute towards hardware, electronic components etc (members get all this stuff for free!) if it’s more than a few bits and pieces. We have a fast Internet connection sponsored by Andrews & Arnold which you’re welcome to use. And a tuckshop!

 

Questions?

Please contact us using any of the methods below!

Twitter • Facebook 16x16.png Facebook • Instagram 16x16.png Instagram • GooglePlus 16x16.png Google+ • Email 16x16.png Mailing List • Github 16x16.png GitHub • Telegram 16x16.png Telegram

New Workshop: Hackspace First Aid

Please note: The date for this workshop has changed to the 22nd of March (1830 to 2200)

We’re kicking off our Workshop series with an evening workshop: Hackspace First Aid.

Hackspaces can be a bit hazardous, depending what you’re doing: sharp things, spinny things, hot things, cold things, laser-y things, poisonous things…

Whilst unlikely, all of these things can hurt you. The aim of this workshop is to share some knowledge on how to respond to accidents that you might see at a Hackspace.

We’re aiming to cover:

  • CPR
  • Cuts/bleeding/trauma
  • Burns
  • Eye injuries
  • Falls
  • Electrocution
Be aware: this is not a First Aid course! It is not ratified by anyone, and you will get no qualifications at the end of it.
Tickets are free, but there will be a suggested donation (TBC) that we would greatly appreciate if you attend, especially if you aren’t a member of York Hackspace.

Register for a free ticket at https://www.eventbrite.co.uk/e/hackspace-first-aid-tickets-42955741780

 

More Open Days, More Workshops, More Better!

It is probably a bit late in the month for New Years resolutions, but York Hackspace never does things by the books, so why start now…? 

An inkjet printer cartridge looking genuinely shocked that a new blog post has appeared

It’s been a while since our last blog post: Since October, in fact. Despite the radio silence, lots has been going on: the laser cutter has some shiny new modifications and upgrades (watch this space for an update!), plans hatched, wood carpenter-ed, mallets crafted, lasers cut, many chocolate bars munched and cans of Coke drunk. We just need to tell people about it!

 

So, York Hackspace has a New Year’s Resolution: BE MORE SOCIAL!

 

This is what we have planned:

 

  • Expect more posts about what we’ve been up to on the blog, Facebook, Instagram, Twitter… you name it, you’ll see it.
  • More open events! Wednesday evenings at 8pm will remain Open Nights, but we will be having regular open days on weekends (to be announced later this week!) so more people can make it down to the space.
  • Workshops: we want to share skills and help people teach themselves about making cool stuff, so expect workshops about laser cutting, PCB making… watch this space!
  • Hackathons: 24 hours of hackery goodness!

Want to keep up to date with whats going on? Follow us at any of the links below, and see ya at the ‘space!

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Debugging a Laser

We were going to write a post a few weeks ago about our new laser cutter. Unfortunately, after a relatively short time, it stopped cutting. This post is about how we’ve gone about diagnosing the problem, since it’s hard to find this sort of information online.

Before I get into things, please be warned: Lasers used for cutting are extremely hazardous – the diffuse radiation from the laser can blind you without staring into the beam, and the carbon dioxide lasers commonly used produce a beam which is mostly invisible! Additionally, the power supplies produce extremely high voltages (on the order of 25kV – that’s enough to cross a significant air gap), and can supply enough current to produce a lethal shock (it only takes 27mA). Don’t do this unless you know what you are doing – and even then, please have someone working with you.

That being said, let me get on with the article!

Firstly – some basics. I’m not a laser expert by any means, but I’ll attempt to describe the requirements around the operation of one. A carbon dioxide laser relies on electrical excitation of the gas molecules to produce radiation, which leads to laser operation. To excite the gas, a high voltage must be applied to the tube, which ionises the gas and “strikes” the tube. Once ionised, the gas begins to pass electrical current, which then sustains the laser operation. For our tube, around 25kV is required to strike it, after which the voltage reduces to around 2kV. The power supply regulates the current supplied, to stabilise the power output of the tube.

The aim of our diagnosis was to determine which of these components was most likely the cause of the fault:

  • The laser tube
  • The high voltage power supply
  • The laser controls

We’d already eliminated the basics – mains power issues, fuses, etc. The next thing we checked was whether there was any sign of laser power. Once we’d determined there was no sign of laser activity, we flipped open the laser cover to observe the tube. We could see some faint glowing around the electrodes, which suggested that there was some ionisation of the gas, but not enough to strike the tube.

The first thing we attempted to rule out was the panel controls. We found the data sheet for the laser supply. The power supply has a regulation input of 0-5V, which controls the current to the laser. On our cutter, this is directly wired to a potentiometer on the front panel. We checked this using a multimeter, and verified that the output varied smoothly, with no jumps or dirty spots. We also checked that the test button was able to drive the input terminal on the power supply, that the panel ammeter was able to pass current, and that the wiring was sound.

Since we had no guarantee that our laser tube was OK, we needed to create a test circuit that “looked” like a laser tube to the power supply. This would then provide a means to check whether the power supply was able to produce the high voltage required to strike the tube, and whether it was capable of supplying the current to sustain operation.

Since testing the supply’s sustain current was the simplest thing to do, we calculated an appropriate resistor value to load the supply. As we knew our tube was a 40W model, and worked at about 20mA current, we chose a 100kOhm resistor (20mA into 100k produces 2kV, 2kV x 20mA = 40W). We purchased a large, high wattage ceramic coated resistor for this, both to ensure sufficient power dissipation, and to be certain the high voltage wouldn’t arc over the resistor. The resistor was wired in instead of the laser, and we used the earth terminal on the cutter’s chassis as the return path, after verifying that this connected to the power supply’s return terminal. We also connected a 100 ohm resistor in series, at the earth side of the power resistor – this provided a 1000:1 resistance ratio, which was suitable for connecting a voltmeter to, so we could see the voltage produced by the supply.

We began testing with our control potentiometer turned all the way down, and tested for a few seconds at increasing levels. The result showed a gradual increase in current with no sign of a problem. We then held the supply at its maximum current (which was about 18.5mA) for 10 seconds to check it produced a steady current.

Laser Supply Tester - Circuit Schematic

Laser Supply Test Hardware

Laser test hardware

Laser test hardware

To test the striking voltage, we used a simple spark-gap setup in series with the resistor. Dry air has a breakdown voltage of about 3kV/mm. We used some bare copper wire to assemble a simple gap which could be varied by bending the wires. While this didn’t provide a way to directly measure the striking voltage, the gap would provide an approximation – with the rest of the circuit acting as a realistic dummy load and providing a means to check the current and running voltage.

Starting with a gap of about 1mm, we tested the supply. At 1mm, we got a nice clean purple arc. Increasing the gap, we got to around 3mm before we hit trouble. At this point, the breakdown voltage was about 9kV, but the supply would only strike with the control potentiometer in a particular position, and wouldn’t sustain operation. Increasing the gap further resulted in no striking at all.

As the laser required around 25kV to strike, this setup should have worked up to a gap of about 8-9mm, so we were quite far off.

This seemed to indicate a problem with the power supply – most likely, some form of insulation breakdown in the flyback transformer.

We’ve since ordered and installed a new power supply, and I’m pleased to report that the laser cutter is now back in working order!