Friday, December 27, 2013

STIGA table hockey custom scoreboard

Hi there ! First of all merry Christmas and happy new year. I am sorry that I wasn’t active for a long time, but things have changed lately. I had to overcome some things, I can’t tell you whether I’ll continue with this blog, but for right now I want to.

So, few weeks back my brother had called me, and he said that he would like to restore an old STIGA table hockey, that we used to play with, when we were younger. I thought it was a great idea, so he wanted me to create a scoreboard, since game itself had only mechanical one that was not very appealing. They also came up with new goals and nets for them and we’ve ordered original NHL teams. So when designing I went for the easier option, so I have found these I2C display modules, because multiplexing eight 7-segment displays with single atmega328 would be suicide. They came right before Christmas, and I brought home with me few tools to put it all together. It wasn’t as easy as though at the beginning since library provided by the seller wasn’t directly for the version of the displays we’ve ordered. That’s the reason why it took me some time to figure it all out. After that it was pretty straight forward. You can see the working scoreboard in the video, also Brandon Dubinsky scoring brilliant goal !


Saturday, June 1, 2013


Hi there ! Last week I had final exams at my secondary grammar school, so I want to apologize for inactivity, but there was no time for that. Good news is that I passed, and I've been accepted to the Brno University of Technology, so I'll be moving to Brno during summer. Thing is that I have almost 4 months of summer in front of me, so I will try to build as many cool things as possible, thanks for your support :).

Sunday, March 31, 2013

Portable Power Supply

Hi ! First of all happy Easter to everyone. If you haven’t seen it yet, go watch my reel, I hope you’ll like it.

Currently I’m working on a project that uses Raspberry Pi, but it requires Pi to be portable. This raises a question of power supply. Of course, I could just use 4 AA batteries or something temporary, but idea of portable power supply has been in my mind for some time. Once again I decided to use Nokia LiPo batteries, since they are great, and I have a lot of them. I used 3 x 1500 mAh ones so it gives me about 4.5 Ah to work with, which is not bad at all. At ebay I found these 3.7V to 5V booster converters, they’re great so I’ve already bought two of them. There was some problem with grounding, because circuit wasn’t working after resetting, so I had to connect battery and output ground with schottky diode, which solved the problem. I decided to put it all in an altoids tin. I still have lot of them from the times when I was building portable circuits. I have to say this thing is a beast, it has no problems with powering things like Arduino, Raspberry Pi or even charging my phone. Only problem is that circuit doesn’t have control of how much is being drawn from batteries, so when I’m charging my phone, circuit is giving out something like 1 ampere, and it gets really hot immediately. But that doesn’t matter since I will only be using it on my bench. Having handy 5V supply available every time is great.

Saturday, February 9, 2013

Observer Reboot [2.0]

Hi ! First of all I want to apologize for not being active for quiet some time. I was working on something big, but it was going slow so I had to make a break and I decided to reboot the observer !

Year ago I lost all of my data including code that was on observer, since that I'm storing all of my data on cloud, and a usb drive aswell. So when I was wondering what could I do with xbee modules, I thought that I could finally write some new code for observer, but at the same time I wanted to make some improvements. So I decided to use control glove, which has a lot of potential, even more now since I've added bend sensor to the index finger. So I've built small bracelet that has xbee inside and antenna. I etched new board for observer, which used a transistor to control whether servos are on or not, but that wasn't working quiet well because transistor wasn't able to provide enough current and to switch servos fast enough and it caused servos to jitter. Reason was that control glove sends data every 50 ms and observer refreshes itself every 45ms in order to make turning and speed control smooth enough. I am also using two power supplies now, because I like to separate logics from servos. It was quiet hard to synchronize data sending/receiving, and as you can see in the video it's far from being perfect.

This is the first time I've decided to make a proper narrated video, so please let me know what you think of it, because if it's bad I will return to the old way of doing short videos with music in background. So if you liked it please like it or let me now in the comments. As for my future plans, I'll get back to that big secret project and I hope, it won't take me lot of time to finish it.