Tag Archives: HAL9k

Speaking “Pyt-knap” / “Never mind button”

A woman working in a kindergarten told me about a button they had for the kids. Whenever there was some dispute between some kids, an adult could ask them to press the button, in order to easen the kids ability to act by the meaning of the danish word “pyt” (meaning something along the words “never mind”).

However it turned out turned out the button was not a button after all but just a sticker! I thought the idea behind the so called “button” and the usage of it was fun, so I decided to make one for the kindergarten.

The solution was straight forward: Make a little box with a laser cutter, an isd1820, a button, a dc plug for the case, a lot of hot snot glue and a 5 V power supply. The box is made of 6 mm ply wood and measures 9x9x9 cm. The hole on the back is covered by the back plate where the screw in the wall is screwed in. To finish it all up I gave it two layers of varnish. If you want to build one your self, the OpenSCAD file is available here and an SVG is available here (the green color in the SVG should only be engraved).

If I later on get a picture or a small video clip of the button in use in the kindergarten, I will update this post.

Pyt knap

Solder fume lamp

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I needed something to remove the smoke when soldering and build this USB powered solder fume fan lamp with an ESP8266 arduino, WS2812b/Neopixels, a fan with an active coal filter and a PIR sensor.

Scad/svg files are available on Thingiverse.

The case is lasercutted in 4 mm plywood.

When there is no movement beneath the lamp the fan turns off after e.g. 60 seconds (can be extended to e.g. 1800 when holding down the fan button) and the LED turns off after 1800 seconds of inactivity. The LED intensity can be dimmed by holding down the LED button.

DSC_0010Parts list:
* 4 mm plywood for the laser cutted case
* Ikea Forså lamp ( http://www.ikea.com/us/en/catalog/products/80146777/ )
* WS2812b / Neopixel strip (30 LED/m, 12 LED’s are used for the lamp. I bought it on Ali Express)
* Level shifter from 3.3 V to 5 V for the 3.3 V output from the PIR sensor (https://www.adafruit.com/product/757 I bougt it on AliExpress)
* 1.5 mF capacitor betwen +5 V and ground near the Neopixels, for evening out voltage drops and ripple from the USB power.
* PIR sensor (https://www.adafruit.com/product/189 I bought it on AliExpress)
* Fan (80 mm, 12 V. It was just laying around)
* Wemos D1 mini (https://www.wemos.cc/product/d1-mini.html)
* Wemos ProtoBoard (https://www.wemos.cc/product/protoboard.html)
* Wemos RelayShield for turning the fan on and off (https://www.wemos.cc/product/relay-shield.html)DSC_0057
* MT3608 DC-DC Step Up Power Module from AliE for the power for the 12 V fan
* Activated coal filter (adjusted the size with a scissor) (https://www.conrad.de/de/aktivkohlefilter-3teilig-toolcraft-79-7201-588546.html i bought it on AliE)
* two push buttons, connecting the pins from the ESP8266 to ground.
* USB cable
* A few strips, pig tail wires, bolt and nuts etc.

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The case is glued together with normal wood glue and the PIR sensor and the WS2812b Neopixel strips are glued against the case with cyanoacrylate. The DC-DC converter is fixed with a cable tie. The Wemos D1 mini is fixed with a small bolt through a drilled hole in the ProtoBoard. The capacitor and the level shifter is glued with a hot glue gun. Be aware that there is very little room for the boards and the wires. If I were to build it again I would make some more room.

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When writing the code it is not so easy to access the ESP8266 once it is mounted inside the lamp, so I made a quick and dirty test setup on my breadboard ( If you like the breadboard, check it out at https://www.thingiverse.com/thing:1842897 ).

Also the “stack” of the Wemos ProtoBoard, D1 mini and RelayShield is higher than the fan + activated coal filter, so it sticks out of the top, which I think is fine. All the parts do not need to be hidden away for the eye to see 🙂

The software is available at:
https://github.com/sman-dk/arduino/tree/master/solder_fume_lamp
Since the ESP8266/Wemos D1 mini has wifi capability future improvements of the software will of course be to make it controllable via wifi  🙂

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Power usage when the lamp and fan is active
Power usage when the lamp and fan is active
Power usage when idle
Power usage when idle

HAL9k; now with awesome electrical and network installation

The local hacker space here in Aalborg (HAL9k) has moved from Rapsgade 1 to a permanent location at Sofiendalsvej 80. For a number of weeks we he been moving boxes of all our stuff, painting walls and other tasks related to the move. One of the things that I was involved in was the electricity installation and the computer network.

We have been so lucky to inherit a large number of metal and plastic cable trays including a number of Ethernet jacks and power outlets reducing the budget for establishing a new infrastructure at the new place.

After a lot of work, 50 m metal, 20 m plastic cable tray and 1,2 km Ethernet cable later we now have 74 ethernet jacks connected to our distribution frame with our two 48 port gigabit Dell switches connected to an OpenBSD firewall in VMware on our Dell R710 server, routing IPv4 and IPv6 (through a SIXXS tunnel). Thank you to Xena for the switches and the server.

The wireless network is handled by a 802.11a/b/g access point. The access point and the directional antennas are actually meant for outdoor usage, so we mounted it on an IKEA table leg to give it a touch of the rustic outdoor life on a large pole…
If you are curious about the details of the network setup check out the hal9k wiki here.

Besides the network installation we have also installed a new distribution board and a lot of power outlets. We have a dedicated power meter for the server room besides the three other power meters (which according to our plan will be monitored by our LIAB) and relays for the groups used in the workshops making integration with the physical access control system and emergency buttons easily done.

 

 

 

 

 

 

 

POS printers and Python

I had this old POS (Point Of Sale) receipt printer laying around for some time and thought it could be fun to play a bit with it. Printing plain text is simply done by sending it as characters via a serial connection. Cutting the paper is some ESC code which i found in a manual online. Printing images was a bit more tricky, since it is requires some specific codes, depending on how the dots in a vertical bar, equal to the height of a character, must be composed. I wrote a small Python module integrating the ability to print images, text etc.  since I could not find anything online simliar to what i wanted.

At the local hacker space (HAL9k) we have now received a large box full of used receipt printers, VFDs etc. and some of the members have asked for the module for printing images so I have uploaded pyPOSprinter to GitHub. It makes use of pySerial for communicating with the printer and Python Image Library for reading image files. The included example also shows how to use pyQRNative to print QR-codes (bar codes are soo last centory 🙂  ).

from pyqrnative import PyQRNative
qr = PyQRNative.QRCode(5, PyQRNative.QRErrorCorrectLevel.Q)
qr.addData(“http://www.sman.dk”)
qr.make()
im = qr.makeImage()
ims = im.resize((525,525))
from POSprinter import POSprinter
printer = POSprinter.POSprinter()
printer.write(“Hello Puffy\n”, align=”center”)
printer.lineFeed(2)
printer.printImgFromFile(“puffy.gif”, resolution=”low”, scale=1.0)
printer.write(“Friske agurker paa glas”, rcolStr=”200 DKK”)
printer.lineFeed(2)
printer.printImgFromPILObject(ims, scale=0.5)
printer.lineFeedCut()

Using QR codes at HAL9k

At the hackerspace in Aalborg (HAL9k) we wanted to mark equipment etc. with various information such as the owner of the equipment, possible instructions on how to use it and other relevant information.

We decided to make something based on stickers with QR codes where the user is redirected to the relevant subpage on HAL9k’s website. One requirement was furthermore that it should be possible to change the name of a wiki page or possibly change to a new wiki/CMS system without putting on a bunch of new stickers, i.e. something more dynamic than a direct link.

With regards to the stickers we ended up with a label printer attached to an Ubuntu Linux PC. We got 1300 stickers (resulting in 2600 QR codes) on Ebay for 350 DKK – enough stickers for the next foreseeable time..

Mikael from the hackerspace wrote some PHP code that we run locally on an Apache webserver on the PC, which basically generates a QR code (well actually two since we have two individual QR codes per sticker in order to end up with the right size), adds some (optional) text, saves the resulting image to a file and then calls the lp printing command.

The label printer was made to work with CUPS by using the instructions on this site.

Now back to the requirement about the desire not having to put new stickers on all the equipment when we change wiki/CMS, rename pages etc. We solved this by letting the QR codes point to http://qr.hal9k.dk/HQRxxx where ‘xxx’ is some number. The webserver at qr.hal9k.dk automatically redirects (307 Temporary Redirect) to the relevant page. In order not to have a manually maintained list that nobody would update anyway i wrote a Python script that every 5 minutes goes through all the pages on the HAL9k wiki using the page hal9k.dk/qr as an index. Every time it sees the string ‘HQR’ followed by a number on a given page, a reference is made and a .htaccess file is then updated so that the user is redirected to the correct page. The mappings between the keys and the wiki pages, logs etc. generated by the script is available at qr.hal9k.dk.

So the end result, besides having fun making it all, is that now users can easily print labels and put them on equipment at the hackerspace. If they forget to create the wiki page the user is automatically redirected to this page for a reminder about just that 🙂