This year, I've developed the game E. M. Wave Jammer. It is the world's first telephone game in Global Game Jam, which is playable by dialing a telephone number.
I FUBAR'd in last year's game jam. Fortunately, I did much better this year.
This game is for entertainment only, no political message intended.
For Hong Kong SAR phone numbers, dial 54839953. For non-Hong Kong SAR phone numbers, dial +85254839953 with skype. We do not accept international non-skype calls to save our operational cost. This game has Cantonese(Press 1), Mandarin(Press 2) and English(Press 3) version. Please notice that this phone number is temporary. It will be changed after I've finished setting up my phonesite.
The game happens in Japan during Cold War era. In the game, North Korea is using advance electromagnetic waves technology for sending signals to Cuba. They are plotting to attack Japan. In the game, the player plays as the role of the commander of telecommunication department. The player is responsible for jamming the signals between them.
For the ease of command, Japan is divided into 6 zones. The electromagnetic waves from North Korea will propagate via zone 1, zone 2, zone 3, zone 4, zone 5, zone 6, all the way to Cuba.
The player is required to use limited amount of electricity to build jammers. Electricity are consumed for building the jammers. No electricity is required to operate the jammers. The more electricity you spend to build a jammer, the more powerful it is. For example, a 5W jammer can attenuate the signal by 5W.
The remaining non-attenuated signal will become military information end up on enemy's hand. When the information level reaches 100%, you lose. The information level is increased by the Wattage of signal received divided by the Wattage of signal sent. There is no way to reduce the information level.
The player starts with 20W of electricity. To generate electricity, generators have to be built. They generate electricity when signal pass thru its zone. For example, a 5W generator will cost 5W to build, and generates 5W of electricity.
Each zone can only have one structure(e.g jammer, generator). New structure building on a zone with existing structure will demolish the existing one. Structures cannot be sold.
After wave 6, there will be Accelerated E.M. Wave signal. It is able to bypass Zone 2, 4, 6. It is sent via Zone 1, 3, 5 to Cuba.
After wave 11, there will be Narrow-band E.M. Wave signal, which includes low frequency E.M. Wave Signal and high frequency E.M. Wave Signal. Ordinary jammers are half as effective against these signal compared with other signals. Therefore, the player is able to build LF Jammers and HF Jammers to defend against these signals. A 10W LF Jammer can attenuate LF Signal by 20W, Ordinary Signal by 5W, and cannot attenuate HF signal. A 10W HF Jammer can attenuate HF Signal by 20W, Ordinary Signal by 5W, and cannot attenuate LF signal.
After wave 16, there will be E.M. Wave from Cuba to North Korea, which propagates via Zone 6, 5, 4, 3, 2, 1 to North Korea. Accelerated E.M. Wave from Cuba propagates via Zone 6, 4, 2 to North Korea.
After wave 21, there will be FM Signal. FM Signals is immune to Ordinary Jammers. It makes non-LF, non-HF FM waves very troublesome to be dealt with because they couldn't be attenuated by ordinary jammers. Yet, HF and LF jammers are only half as efficient to deal with non-LF, non-HF waves.
Before the Jam, I've developed the hardware Dinbo Prototype B as well as its library libdinbo. I've also made a template for developing any telephone system based on this library.
In addition of the telephone system, I have also practiced using LMMS, Labchrip, Audacity, SoX, just all of the software that I planned to use. I also planned to practice Aegisub for making video subtitles. Unfortunately, I didn't have enough time and the Jam day had come. :(
Just like the last year, the 48 hours game jam spanned across three days.
In the first day, I've arrived at the venue, before the event started, I've found a bug on the library of Dinbo Prototype B that made it failed to detect DTMF touch keys properly. Fortunately, I fixed it right before it started.
After that, I've listened to the briefing. After the theme Waves was announced, I came up with this game design quickly. Since I was working solo in this jam, this process went way quicker than the jam of previous year. :)
Here is a photo of my game design document. As you see below, it is only one A4 page. It is poorly-organized because I'm the only intended audience of this document. :P
Some of the features are strike'd out at the design stage because I foresaw that it couldn't be completed within 48 hours.
Here is a photo taken from day 1 of the event. Sorry for phone camera quality:
There were many jammers in our Jam site, and the Hong Kong SAR was the 8th largest out of 700+ jam sites all over the world in 2017!
With the experience of last year, I won't sleep on-site because I couldn't. At the end of the day, I went to home and took a rest.
Although I slept much better than last year, I still didn't sleep enough. Therefore, I woke up late. I started programming. Feeling dizzy, I took a nap after an hour of development. Then I woke up again and continue. To save some traveling time, I decide to jam at home this day because I was solo and I didn't need to go to the site to collaborate with my teammates.
With software emulation feature of the libdinbo, I was able to develop the game without dialing the phone number. It saved me some cost of calling the number.
With existing code base, the development went smoothly. I managed to implement the game play. After midnight, I started translating the game into Mandarin as well as English. I have also synthesized and recorded some sfx. Originally I also planned to make music and recording the Cantonese voice myself. Considered that I need to prepare for the presentation, I decided to drop these features and went to bed. All of the development works ended here. However, I still haven't deployed it on the Dinbo Prototype B hardware.
I (almost) dedicated this day for preparing for the presentation. I decided to prepare for the presentation before deploying it to the hardware. That is because the deadline of submitting the presentation was very tight. And preparing presentation before the deployment can buy me a bit extra time.
I started with recording the gameplay audio using the voice log function of the libdinbo in its software emulation mode. It went quite well and I've recorded a 9 minutes audio. I had cut down the audio to 4.5 minutes.
Then I asked the volunteers about the time limit of presentation. Turned out that each team would only be given two minutes to present their game. Well, I thought that I had 5~10 minutes. :/
After that, I further cut down the audio to 1.5 minutes. Even the gameplay instruction were removed.
So how did I explain the gameplay? Simple. I used Libreoffice Impress to make some presentation slides to visualize the game play frame by frame. Then I played the gameplay audio and used vokoscreen record the voice and the presentation slides. I clicks as I record and play the gameplay audio. After that, I used ffmpeg to trim beginning and the end of the video. Then convert the video format to webm. Here is the demonstration video in Cantonese.
After that, I prepared another powerpoint file. I planned to use the powerpoint before playing the demonstration video.
Everything went well, except that the deadline was very tight. I had to do everything I said above within like 3~4 hours. Then I uploaded my video to the website of Global Game Jam and sent the powerpoint to the staffs. After that, I have deployed my program to the Dinbo Prototype B hardware.
Here is the presentation session(the guy who is presenting in the photo is not me):
It didn't went very well when it was my turn. I thought that I could access a presenter's mouse so that I could show my powerpoint with animation. I thought that I could click the powerpoint myself. Unfortunately, the presenter's mouse wasn't working somehow. Then the staff of my jam site just random clicked his mouse, causing the slides shown up earlier than it was supposed to be shown. After that, the staff was trying to click on the gameplay demonstration video link inside the last slide of my powerpoint. But he forgot to enter presentation mode and couldn't click on the link. It looked very bad for the audience. :/
Nevertheless, the gameplay video was found to be funny by many fellow jammers. I enjoyed their laugh and applause at the end, and I earned a certificate of participation. :)
After that, I have introduced my final year project to my fellow jammers. Then I have interviewed some of them about my project. That is helpful for me to improve my final year project. :)
Finally, it was the closing ceremony of the event. As I have expected, I got no award because I'm solo. Apparently the sponsors of our site is reluctant to give out awards to solo teams. :P
Anyway, I have completed the game during the 48 hours. I have proven that libdinbo is working and I have shown my final year project to others. It is a great success compared with the previous jam.
After the jam, I have talked about the event with people from other jam sites via the Internet. Someone who joined the site of Tokyo University of Technology shared an interesting photo of the site(photo used with permission by the copyright holder of the photo):
Apparently the jammers in Tokyo University of Technology site had more fun than we do. Instead of giving out awards to well-performing teams, they had a pizza party! And the award was the game itself that the jammers developed. It is a better match to the sprite of Game Jam.
I'm performing much better in this game jam than the last one. And this year is much more fun for me. Here is what went well:
Overall, The Jam of this year went pretty well. And it was a quite memorable experience. :)
The Game Jam of this year is very special for me. It has some strategical value. As you may have noticed in my previous blogpost, Dinbo Prototype B will be a successor of the existing telephone system, Dinbo Prototype A. Dinbo Prototype B will be used for the following purposes:
This game jam helps improving the code base for Dinbo Prototype B, particularly, the internationalization functionality of the code base was enhanced during the jam. In addition, it's also a good way to test whether the entire system works. If a game can be developed for this system, then it would definitely be possible for me to develop my final year project using the same system.
That says, my mission of Global Game Jam 2017 is accomplished. Now I got to work on my final year project as well as my phonesite. :D
Want to read more? A parallel jammer in Japan had made a blogpost of his game - Super Smash Tokyo
Hey guys! Finally I got time to blog about the technical details behind the whack-a-mole game.
Click here to view the previous part of this blog post, which is a release announcement of this game.
The game is powered by Dinbo Prototype A, which is a telephone system that I developed using SIM900A module with Raspberry Pi 3.
The schematics diagram of the system is shown below:
I knew. This system is stupid. Instead of connecting the mic and speaker of SIM900A with Raspberry Pi, GPIO is used for voice communication between them. To make the thing even funnier, an ATtiny13 is used as an ADC.
Anyway, this is just an early prototype. I just wanted to tinker around with the electronic parts that I have. And this design suits the purpose very well. More importantly, this system works. :P
Here is how does the SIM900A and ATtiny13 look like after everything is connected:
As shown above, the entire system is deployed on a breadboard.
Due to the high current requirement, multiple breadboard wires is required for the power supply of SIM900A. A capacitor is also connected between VCC and GND to smooth the voltage level over time(not shown on the outdated photo above).
Many programs were written for this system. They are ATtiny13 ADC program, serial multiplexer program, voice to socket program, and the whack-a-mole program. All of these programs are written in C.
The ATtiny13 ADC program, as its name suggests, is a program installed on the microcontoller for the purpose of converting the analog voice signal from SIM900A to time-based digital signal. When a "get sample" signal is received by PB1, it will read the analog input of PB3 send a digitized signal via PB4 to Raspberry Pi. This is the first non-Arduino embedded program I have ever developed. I had some fun on reading the specification of ATtiny13. The library avr-libc was used.
The voice to socket program is a program that converts the digitized audio signal received from the ATtiny, then send it to the whack-a-mole program using unix socket file. This is the first real time program I have developed in my life. To achieve real time execution of code, a CPU core is reserved solely for the linux process of this program.
The serial multiplexer allows multiple programs write to the serial interface of SIM900A. It redirects all of the data received from socket to the serial interface. It is adapted from this program found on Stack Overflow.
The Whack-a-mole program works by communicating with the serial multiplexer as well as the voice to socket program. It also detects DTMF tones by processing the audio signal received. Other than that, it is just like other C programs.
The source code of these programs are poorly organized. I still don't have time to package them. There are also some copyright issue on the serial multiplexer because majority of code is taken from the Stack Overflow answer with unspecified license. Therefore, I cannot release these programs too publicly. However, a copy of source code can be requested by email and they are considered on case-by-case basis.
For the final year project of my college, the development of Dinbo Prototype B is started, which will be a successor of the current system. Standard analog audio interface will be used(instead of doing the analog<->digital conversion hack using GPIOs). I also plan to solder it on a perfboard.
The library will be written in Python, which is much more flexible than C. It will be mainly designed for non-game telephone systems. However, it should be possible to make a game with it. After the completion of the library, I'll port this game to Dinbo Prototype B. I will update you guys about any news on it.
Sorry for not updating for a while guys.
Spent almost $100 on hardware and stuffs, worked for more than a month, Whack-a-mole over telephone is finally completed!
各位! 好耐無打廣東話嘅blostpost. 耗資陸佰港元. 動工參拾陸夜. 小弟嘅電話扑傻瓜終於搞掂喇!
Behold the gameplay(Cantonese with English subtitle)!
The gameplay is simple. First, dial the number 5517 6408 in Hong Kong(does not accept international call, Cantonese only). Then, when you hear certain sound, you'll have to press certain key. The sounds and the keys are randomly generated. If you press the correct one, you get a score. When it reaches the threshold, the difficulty will be increased as shown below:
Level 1: Score requirement: 0; Three random animal sounds. Each requires the player to press a key.
Level 2: Score requirement: 10; Three additional random synth'd wave sounds. Each requires the player to press a key.
Level 3: Score requirement: 30; Three additional random voice of numbers. Each requires the player to press another key that is usually inconsistent with the number that the player have heard.
Level 4: Score requirement: 60; After this level, the player has to press certain key for every 5 sounds, regardless what is the sound that the player has heard.
Level 5: Score requirement: 100; Upon hearing any of 5 random sounds, the players has to press a key. Upon hearing another 5 random sounds, the players has to press another key. Upon hearing yet another 3 random sounds, the player has to press yet another key.
遊戲玩法好簡單. 首先打5517 6408(唔收國際電話, 唔收133電話), 跟住佢就會叫你聽到某D聲就要撳某D制. D聲同D制係隨機嘅. 撳啱加分. 夠分就LEVEL UP:
LEVEL 1: 所需分數: 0; 三個隨機動物聲. 每個聲要撳一粒制.
LEVEL 2: 所需分數: 10; 三個隨機電腦合成聲. 每個聲要撳一粒制.
LEVEL 3: 所需分數: 30; 三個隨機數字聲. 每個聲要撳一粒制, 而嗰粒制通常唔係你聽到嗰個數字嘅聲.
LEVEL 4: 所需分數: 60; 每聽到五個聲就要撳某一粒制.
LEVEL 5: 所需分數: 100; 聽到某五種聲要撳一粒制. 聽到另外某五種聲要撳另一粒制. 聽到另外某三種聲又要撳另一粒制.
If you press the wrong key, or if you're too slow, then you lose. If your score is the highest among everyone else, the score will be recorded.
如果你撳錯制或者撳得太慢就會輸. 如果你嘅分數係最高嘅話, 個分將會被記錄.
Alright! That's it for the first part of the blogpost. The second part will be about the technical details of this project. See you! :)
Better to be late than never announcing it. The Poland Event website is closed.
The hoster could not pay for the hosting fee. Therefore, the site is closed about a month after the begin of the event.
Considering that the hoster is relatively young, he is a genius of being capable for setting up a website for the event.
Give a big hand to Eruverio! Our hoster/organizer of the RPS tournament 2016!
We will definitely host another event next year! I'll probably find someone who is capable for keeping the site alive for at least a few years.
The system runs out of RAM
Kill RAM intensive processes, or use swap.
I have installed CUPS on my Raspberry Pi. It was connected to a USB printer and made it accessible via my LAN. It had been working very well until the recent. In these few weeks, somehow the printer does not print.
I entered the CUPS web interface of my Raspberry Pi and tried printing a test page. Funny enough. It claimed that the print job was completed, despite that the printer did nothing.
Then I dig up /var/log/cups/access_log. Here is what's inside.
localhost - - [10/May/2016:14:37:12 +0800] "POST /printers/Canon_MG2400_series HTTP/1.1" 200 422 Print-Job successful-ok
It claimed that the print is a success. Obviously that's not true!
Then I dig up /var/log/cups/error_log. Unfortunately, there was nothing inside.
Then I started trying stuffs like:
None worked! :(
Then I figured out that there is something called LogLevel in CUPS config. I modified it as follows:
And I restarted CUPS. Then I noticed the following messages appeared in /var/log/cups/error_log:
D [10/May/2016:14:37:20 +0800] [Job 136] Error: /undefined in --setpagedevice-- ... D [10/May/2016:14:37:20 +0800] [Job 136] Last OS error: Cannot allocate memory D [10/May/2016:14:37:20 +0800] [Job 136] GPL Ghostscript 9.05: Unrecoverable error, exit code 1 ... I [10/May/2016:14:37:22 +0800] [Job 136] Job completed.
What? Obviously something went wrong! How on the earth could the level of that message merely be a debug? I think that should be at least a warn! More importantly, how come it is called "Job completed"? I think that should be "Job Failed" instead! :<
After that, I increased the swap space. And remote printing starts working again. :D
Took me a few hours to figure that out. I couldn't find this solution in Google. That's why I blog about this. Hopefully someone somewhere would somehow find this blogpost helpful.
UPDATE: I've filed a bug report to the CUPS developers. Hopefully it will be fixed soon.