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.

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.

PF 2013 !

I want to wish you all a great year full of joy and happiness !

From my perspective year 2012 was really good, I feel like I moved to a next level with my skills and everything. I build my best project yet - Bracerbot, which is still not finished, but I am really happy that I was able to bring my ideas to real world. Good news is that for Christmas I got tablet with the pen ! At first I thought I wouldn't be able to fully use it since I'm not an artist, but then I sketched some things and here you can see some things that come out. So I will maybe create new category called concepts for things that I have in mind, but I can't really realize them.

So what's next in 2013 ? Well I hope a lot more projects that you will like (I will probably start with that Biped on picture).

Merry Christmas

I want to wish you all Merry Christmas !

XBees have arrived !

Hi there ! Reason I was inactive for some time is that I was still setting up at a new flat.

 

I am also waiting for some things I've ordered from e-bay. But big news, Christmas have come earlier this year, as I've ordered 2 xbee modules from local store and I already have them ! I spent some time with setting them up, but eventually I was able to send data between them. I'm quiet happy that I've acquired them, and I'm looking forward to use them in some future projects. There is one problem though, I bought ones without antennas (not even surface mount ones), they have only u.fl connectors, so I need to buy some, because range now is only about half meter. I hope I'll be able to finish my next project before Christmas, but it all depends on whether things I've orders arrive soon enough.

First steps with Raspberry Pi

Hi there ! I've been inactive for few weeks because we have moved to a new flat. It's in the same city, but my PC was disassembled for few days and I'm still putting together my workplace.

In spite of that, I've been playing with Raspberry Pi and this awesome Bluetooth keyboard, that has already arrived, and a I have to tell that it's amazing ! No problem with pairing, charges really fast, can be connected to virtually anything, has amazing function keys, USB Bluetooth dongle can be stored in it and it has laser pointer and back-lighted keys ! I have to say it's one of the most useful things I ever bought. Raspberry Pi itself is amazing as-well, I wasn't expecting it to be fast, actually I've expected it to be slow as hell. At first I used Occidentalis from Adafruit as OS, but it turned out that there are some issues with the kernel and the new model of Pi that has 512 MB RAM, so I downloaded newest Wheezy, which is basically debian. I myself prefer Ubuntu, but on a piece of hardware like that, you don't wan't to waste any of your processing power. First thing I did was that I've overclocked ARM 11 processor from 700 MHZ to 950 MHZ and with 450 (usable) MB or RAM this device has quicker response than I've imagined, of course if you're installing something via terminal, it takes a lot of time. Second thing I did was that I've used a small script to automatically bind that Bluetooth keyboard to Raspberry, because it's not wireless, but bluetooth keyboard so you have to connect it manually. This script allows me to work with this keyboard immediately, with no need of wired keyboard or mouse. After that was done, I wanted to play with some GPIOs, but there was a problem, ribbon cable. I only had 40 pin one, and Pi uses 26 pin. So long story short, I've 'adjusted' cable with some pliers for metal and hot glue.

After that I downloaded Geany, which is really lightweight IDE for various languages. Then you need to download RPi.GPIO library via terminal and you're good to go. This was first time when I saw python, I have to say I like this language, it's easy, simple, portable yet have lot of possibilities. So if you're considering buying Raspberry Pi, I recommend you to, because for that amount of money it's an amazing piece of hardware and it's really fun to play with and you can definitely expect some projects that will use it.

Raspberry Pi

Hi ! First of all I would like to thank all of you, because I've recently hit 50,000 views on youtube ! It makes me proud and motivates me to do more and better stuff.

Next important thing is that my Raspberry Pi has finally arrived ! (it took 75 days) Original one that I've ordered got lost, so they had to send new one, on the other hand it's probably even better, because they've send me new model B with 512 MB RAM. I've already bought HDMI cable, Acrylic case and SD card. I want to make my raspberry fully portable, so expect some mods in near future, for that reason I've ordered this mini bluetooth keyboard with mouse pad from ebay. It's small, portable, wireless and uses only one USB port.