Introducing iZac, the Android Bartender
Posted by Nick Johnson | Filed under iZac, android, barbot, adk, arduino
In a previous post, I alluded to a larger project I was working on in the physical/electronics/maker world, and now after much development, I'm pleased to present iZac, the Android Bartender!
A while ago I was inspired by Drink Making Unit 2.0 by Evil Mad Scientist Labs, and decided I wanted to build my own barbot. In this post I'll go over the high level details of what I did and why I did it.
One problem with any drink-dispensing machine is the difficulty of sourcing parts for interacting with food liquids. Pumps are expensive or impractical, valves are likewise problematic and difficult to obtain. My original intention was to use syringe pumps - effectively a DC motor hooked up to a threaded rod that pushes a syringe plunger in and out - and that was the reason behind my making the motor driver shield I wrote about previously. Unfortunately, syringe pumps turned out to be too fiddly and unreliable to use for the barbot, so I had to look for an alternate solution.
I ended up using a similar approach to that used by the DMU2.0, employing a battery powered aquarium pump to pressurize the ...
Building a stackable motor driver shield for Arduino
Posted by Nick Johnson | Filed under busdriver-shield, i2c, avr, arduino
Hi, Hack a Day readers! If you're just looking for the source and schematics, they're here. Otherwise, read on!
Recently I've been working with embedded electronics a bit for a project I'm working on, using an Arduino. For the project, I need to control a number of low-power DC motors, and while there are plenty of solutions out there for driving one or two (or even three) like this, none of them let you drive as many motors as I need, and none of them are stackable, as they all require exclusive use of some IO lines. I could get several standalone driver boards like these, but I didn't much like the prospect of the ratsnest of wiring that would ensue. So, I decided to develop my own.
Before I go on, a brief aside about motor drivers. Motors can require a lot of power, so powering them directly from a microcontroller's IO pins is not practical. The obvious solution is to use a simple transistor, but in many cases, including mine, it's necessary to be able to drive the motor both forward and backwards, which isn't possible using a simple transistor ...
Using the SM130 RFID/NFC reader
Posted by Nick Johnson | Filed under python, sm130, rfid, nfc, arduino
Long time no blog, I know - and this post isn't even my usual. Don't worry, more posts are coming soon!
I've recently been playing around with Arduino, and with NFC tags and readers. Sparkfun (and their Aussie distributors, Little Bird Electronics sell a rather nifty NFC reader/writer, the SM130, by Sonmicro, along with a corresponding Arduino Shield for it. It has a fairly easy to use serial protocol, and supports both regular UART serial and I2C.
In order to use I2C, though, you need to flash the reader with a new firmware. Sonmicro will provide you the firmware for free, b ut the application to flash it to the device is Windows only, which puts a bit of a crimp in the plans of those of us who don't use that platform. I wanted to use the reader in I2C mode, so I decided to try and solve this not just for myself, but anyone else in the same situation.
First step was to obtain the firmware. Sonmicro promptly sent it to me when I asked, and even kindly agreed to allow me to redistribute it - so here it is, in a gist.
The first ...