Countdown Events Box

Countdown Events Box is an incredible IOT vintage machine! It displays the number of remote days of important life events... like your cat’s birthday or the date of your wedding anniversary! :-)
Each event is symbolized by a NFC card with a custom text, picture or drawing. If you put one of them on the Countdown Events Box front panel, then the number of remote days is displayed.

Design of Countdown Events Box is very cool and vintage! The case is made with an old radio flip flop clock. It is a RD100 manufactured by ELAC Germany company in 1972. 3 Nixie tubes display the number of remote days. It is a orange GN4 tubes manufactured by ITT company in 1960s. Finally, on the bottom of the front panel, there is an area to put your entire NFC cards…

There is big rotary switch on each side of Countdown Events Box. First one is used to setup the Nixie tubes brightness, the second to setup the automatic switch off duration of the display.

To setup the event date of each NFC cards, launch dedicated web application with your favorite browser, set the event date with datepicker and click on save button. At last, there is a status led. This one blinks at each time a notification appeared. Indeed, for each event, you can set 3 different values of reaming days. When one of them as the same value of reaming day number, notification is generated. For example, your want a notification 1 week before mum’s birthday, just in case of your missing to buy a beautiful present... So, in web app you set 7 (days) in event notification field. 1 week before her birthday, the led starts to blink. To erase notification and stop LED blinking, your must put the correct RFID card on the machine.

There are no limit of RFID tags, so you can manage, for example, all the birthday date of your 1000 colleagues of your big company!

• 1x Old radio clock ELAC RD 100 (Ebay)
• 3x Nixie Tubes GN4 + holder (Ebay)
• 1x RFID reader MFRC522 (Ebay / Aliexpress)
• 10x NFC cards (13.5MHz) (Ebay / Aliexpress)
• 1x Photon board from Particle with header (store.particle.io)
• 2x rotary switch PEC11R from BOURNS + Knobs (Mouser)
• 1x 5mm orange led 20mA (Mouser)
• 1 power supply AC/DC IRM-10-12 from MEANWELL (Mouser)
• 1 DC/DC 12V to 5V R-78E5.0-1.0 from RECOM (Mouser)
• 1 DC/DC 12V to 200V dedicated to nixies (Ebay)
• IC high voltage driver HV5522 from MICROCHIP (Mouser)
• IC ULN2803A (Mouser)
• Several resistors 1/4W, wrapping wire, solderable breadboard, dip pins (Mouser)
• Plexiglass 3mm black and yellow sheet (local reseller)

Buy an ELAC RD 100 (Ebay, antique store) then disassemble it. Remove all electronic parts (flip flip clock, electronic board, speaker,...) and keep cases and screws.

It is also necessary to remove the front black panel. This is little bit complicated because front panel is sticked to yellow part. To remove it, used a Dremel tool with precautions. At the end, you must have something like show on the pictures.

All new elements of Countdown Events Box (Photon board, Nixie tube, NFC tag reader board) are fixed on the new frame. This frame is also used like a new front panel. It is a assembly of a set 3mm back and yellow plexiglass parts. These are cute out with a laser cutter, then all parts are ready to be glued in place after a quick check for fit.
Don’t missing to put the four M3x50 screws. This screws are used to put in place the plexiglass part having function holding Nixie tubes.

You can find below the vector *.pdf files. One to black parts, second to yellow parts.

As you can see on the hardware overview diagram, The heart of Countdown Events Box is Photon board manufactured by Particle. It is a very efficient board (Arduino spirit) with wifi connection and cloud functions. At the first power up, setup the Wifi with the smartphone apps from Particle and it’s all. After all actions are managed through wifi (configuration, upgrade firmware, etc).
The Photon board drives all other elements: Nixie tubes, tag reader board, rotary switches and event LED.

Power supply

The Countdown Events Box is directly connected to mains. A small AC/DC is used to convert the mains voltage (230V/50Hz or 110V/60Hz) in a 12V dc low voltage. A small mains fused is added to ensure short circuit protection.

The Photon board must be supplied in 5V, to do this, a DC/DC converts 12V in 5V. To supply the Nixie tube, 200 DC voltage must be generated, so another DC/DC is in charge to do this. The NFC tag reader board is supplied directly by Pothon board in 3.3V.

Nixie driver

To drive Nixie tubes, HV5522 is used. Each 10 cathodes (one per numeral) of each tube is connected to the high voltage output of HV5522. Anode of each tube is connected through a resistor 470 Ohm to 220 DC voltage. As you can see in datasheet, the logic voltage of HV5522 must be around 12V. So ULN2803A driver is added to shift Photon logic level (3.3V) to HV5522 logic level (12V). The ULN2803A is also used to drive event LED.

Other hardware parts

The NFC reader is connected to Photon board through SPI. The two outputs of each rotary switch required filtering (debouncing) before be connected to Photon board inputs. The filter is made with a capacitor and resistors as you can see in rotary switch datasheet.

There is 4 small board, this ones are produced in prototyping board (solde-rable breadboard). All are screwed (M3 screws + 8mm spacers) on the main frame:

1. Power supply
2. Photon board
3. Nixies drivers
4. Rotary switches filters

Cut the prototyping board, then solder all components on it.

Note: The package HV5522 is TQFP 48 pins smt package. Use a 44 pin TQFP Dip Adapter (44PINTQFP from futurlec.com or Aliexpress).

Electrical wiring is made with yellow wrapping wire. Each wire is soldered on the dip pin and the a small heat shrink tube is added on it. It is a tedious but necessary step!

It is time to send the CountDown Events Box firmware to Photon board. You can find all the embedded software on github: https://github.com/Totologos/countdown_events_box_embedded. Clone it and open it with a Particle IDE software. Build the project and upgrade the firmware to your Photon board.

The web app is used to setup the event date of each NFC cards. It is made only in Javascript, so it is not necessary to use a specific server (with PHP or Apache).

Just clone the repository on GitHub : https://github.com/Totologos/countdown_events_box_web_app/ and copy all files on your favorite directory. Before to launch index.html, you must setup the photon_id and particle_token variables in cde.js and maybe update the path of all *.js file in index.html

Warning: the photon_id and particle_token are confidential and critical data. So if you put the web application on public web server then restrict access of main directory (with .htaccess file for example).

The NFC card drawings that you can see on pictures are made by M/. If you want a copy, ask her (see credit section to contact)!

The cheaper method is simply to print the pictures on paper, then cut and stick on NFC cards. You can also use an adhesive vinyl sheet, the result is really better. The best solution is to print directly the drawings on the NFC cards, but for this, you must have a specific card printer manufacturer by Evolis for example.

All this project are developed in partership with Le Petit Fablab de Paris. Many thanks to them! Thanks also to M/ artist for the beautiful drawings of each event.

Next steps:

• More efficient web application with user account (login / password).
• Design a new case in wood or plexiglass because the Elac old radio clock is not easy to find and buy!
• Made a PCB to reduce the wiring time.
• Why not manufacture a little quantity of Countdown Events Box and sell or swap with another fun object… maybe in Kickstarter or other...