I’m filing this one under useful tricks. If you’ve got a password field the browser has saved and you can’t recall the text (and you’re too lazy to check the browser password save dialogue), fire up Firebug and press inspect. Target the password field and click. It will pull the HTML up into the screen. Click on type=”password” and change password to “text”. This should display the password in plaintext.
Passing the kid test
Sunday, August 10, 2008
I’ve had the Solenoid project working for about a week and a half now, but the rain and lack of sunlight was getting in the way of making a video of everything in action. It worked out well because it gave me the chance to demonstrate the project to a number of visitors today, all at once. And, as the photo above demonstrates, the project passes the kid test.
The project is still in need of refinement, but I’m thinking that’s where things would get expensive. I’ve sourced out some new solenoids that could be used in a multimedia environment, I’m just unsure of the cost. The solenoids I have used are $7 washing machine parts. Specialty valves are bound to be more expensive. Some of the valves leak, and I’m pretty sure it’s not occurring in the sections I’ve sealed, the valves may be defective, or they may have a scratch in the plastic I created when I was reconfiguring the orientation of the connectors.
The brace you can see in the photo on the left was constructed to correctly position the hoses in sequence. the centre photo demonstrates the digital radio, Arduino, and transistor controller. The green wires leading out of frame are wired to the Solenoids. On the right, the solenoids are hooked up to the hoses. (All the photos have notes visible in Flickr)
In the above video, I’ve got the device filled with water, and directed through flexible hoses. Valves 2, 4, 6, 7, and 1 turn on. They then cycle off, leaving valve 1 open. The camera then pans up to the controller where it zooms in on the LEDs which I’m using as indicators of which valves are turned on. We then go through a test of all the valves on and off to demonstrate the flow when everything is open. A couple of the valves don’t work, and I’ve traced that back to a point on the controller circuit that I think has not been soldered correctly.
I think it would be important to note the projects out there that are doing the same thing. The Jeep waterfall was unveiled at a Detroit autoshow in 2000. This waterfall was published on the Make blog just the other day. MIT’s building made of water is scheduled to open at the 2008 Expo, they’ve hired Lumiartecnia to produce the valves. Also check out this water keyboard for its innovative use of sensing electric resistance when you touch the water to control the solenoids — in this case controlling air flow in a liquid. All these examples show that the envelope can be pushed that much further, and that there’s a large degree of possible variatons.
Still lots more ideas to play with, but many of these will be with the code. I’ve got some really interesting image processing ideas coming up.
Controlling 3DS Max from Arduino
Tuesday, July 15, 2008
My brother, Neil has been playing with an Arduino too. Here’s his latest script for controlling 3DS Max via Arduino:
XBee Solenoid Controller
Sunday, July 13, 2008
This Solenoid controller has been filled with a ton of small successes. Today I’m chalking up one more success to the list. I’ve got the XBee portion of the controller working. I had been working on this for a long time now, and the more I work on it the more I see the potential in this platform.
XBee Solenoid Controller from Eightlines on Vimeo.
The issues I had getting the XBee to work appear to be common based on the message board threads I have seen:
- Upgrade your firmware. The listing on the website is not necessarily in order. I had assumed that since I had 1.0.8.4 I was one version off the most current. After reading the tech docs there were not that many features I appeared to be missing. The 1.0.A.n firmware appears to be a far more advanced stream, use it whenever possible. X-CTU appears to order this list in a more straightforward manner.
- If you don’t have a USB-TTL adapter you can run an Arduino headless (remove the ATMega168 chip) to communicate directly to the XBee. Remove the chip with an IC extractor so you don’t bend the pins. Even better, you can leave the IC in place and communicate directly with the XBee via the Software Serial library. I ended up doing all three methods.
- M. Yarza has an excellent sheild for the Diecimila. I’ve since switched over to the Arduino Nano, but I’m still using this one as a remote connection.
- Build out Tom Igoe’s XBee Terminal to communicate with the XBee. It correctly sends the “+++” Command mode initialization without a carriage return (“\r”). It also displays results on a new line making for reading the settings much easier. I had started by using the OS X Shell but this was much easier. In fact, buy the book Making Things Talk. It explains all this stuff in plain english.
- The RSSI Graphing was useful. You can see how this could be used to trangulate position of three+ Xbee’s.
- Check out the XBee API Library for Processing written by Dan Shiffman and Rob Faludi. This makes the connections to the XBee API mode simple.
- The XBee Analog Duplex script was somewhat confusing, but explains the methods used to communicate from peer to peer. Note, in all of the tutorials, I’d love to see more documentation stating which is the base XBee and which are the remotes. It gets confusing when you can’t figure out which is which.
- Mark the radios themselves with indicators. I’ve added permanent marker dots to designate which XBee I’m looking at. Write down the corresponding configuration settings somewhere you can see them. It will save you polling the chip every time you need it.
A Simple redesign
Wednesday, July 2, 2008
If you can’t explain it simply, you don’t understand it.
— Albert Einstein
The big issue I was having with the Solenoids was too much pressure. So while on a trip to Sudbury my Stepfather and I redesigned it. Well, I just told him what I was thinking of doing, and he came up with a much simpler way of doing it.
It’s a good thing too, because I’ve easily broke the budget on this project! So this design uses a cap from a sewage pipe, and some garden hose adaptors. No soldering required. The pressure in the system is regulated by the height of the pipe and how much water is pumped in. When the solenoids are open and the water is draining a plunger falls, triggering an aquarium pump to refill the container. It stops when the plunger rises past a certain point.
Yes, this thing is now an electronically controlled toilet.
Off to buy some more parts, wire up the XBee controller, and waterproof the remote breadboard.
Listo Destructo
Tuesday, June 24, 2008
So the guys at the electronics stores are loving me lately. I’m pretty good at destroying things. While electronics is a reasonably affordable hobby, I’ve managed to turn it into something a little more extreme. So without further adieu, here’s my “listo destructo”:
- ATMega168 IC — I was using a headless Arduino as a Serial connection. Removing the ATMega IC each time I had to reprogram the XBee chip. Missing one vital component, an IC extractor. The extractor is cheap, at least cheaper than a replacement IC. If you bend the pins once removing the IC by hand, don’t do it again… and again… and again. In the end I bought a new ATMega168, IC extractor, and USB-TTL module so I wouldn’t have to extract it again. (But at this moment the Arduino is sitting on my desk headless)
- HM55B Digital Compass — Red wire, Black wire. Its not that difficult is it? I thought it would save time to just use my existing precut Green wire to wire up the Digital Compass. Wasn’t getting the response I wanted. Turns out I had the positive and negative reversed. Whiff of the burning silicone smell. Definitely not getting the results I want anymore.
- Battery Holder & Two AA’s — Smelled that awful burning smell again last night. Ripped out the power going to the XBee’s, Arduino, USB-TTL. Now I see wisps of smoke coming through the air but nothing’s plugged in. Start throwing papers off my desk to find the culprit. Where there’s smoke there’s two AA’s shorting out. Unplug the AA’s with my IC extractor and promise myself to wire up a two pin plug and clean the desk. (It’s still messy)
- Countless plumbing prototypes — I’ve resoldered the Solenoid structure about ten times now. Still don’t have a final result I’m pleased with. Still have another design up my sleeve but I haven’t spawned the courage to start building it.
- DVD Player — This one’s a good one, I’ve identified hundreds of components scavenged from a DVD Player that didn’t work anymore. IR Emitter and receiver, momentary switches, capacitors, RGB Jacks, connectors, motors, and a frickin’ laser beam. To think this DVD player cost $30. Easily aved me that cost of buying all these little parts at Radio Shack.
- Inkjet printer — Again, tons of little components. Varistors, servos, gears, USB jack, power supply, zener diodes, etc. I’m thinking someone should make a website documenting all the components we can dig out of discarded things. Made a mental note to get rid of the plastic casing before my basement fills up with junk.
- Nintendo Powerglove — I think I just heard hearts shatter. This one was destroyed about two years ago, but it counts in this list because I’m using the parts for one of my project. Recovered Ultrasound emittors and receivers, flex sensors, etc.
One of the guys at work said I probably shouldn’t put a price list on this. I have to agree, it would hurt too much. Oh and this is by no means a complete list, I intend to update as I keep making stupid mistakes.
Arthur Ganson - Sculpter
Tuesday, May 27, 2008
TED is always an excellent source of inspiration. Arthur Ganson has one of the more magical demonstrations I have ever seen. What a fabulous body of work!
Treasure Hunting at the Surplus Store
Saturday, May 24, 2008
Sometimes its worth venturing out to a disorganized surplus store to see what you can find. This is my latest little toy.
Its a fragment of a pixelboard. Alternate the currents from one pin to the other and you can make the yellow dots flip to black. The cool thing is even powerless it keeps its state. If you manually flip the pixel to the other side it returns based on the magnetic pull.
The guys at the store obtained it from a signage company that was dumping their old stock for TV screens. The destroyed all of the control boards because it was proprietary technology (just a couple relays I’m thinking). The larger versions of these pixelboards also come with LEDs to illuminate the structure.
In the photo above I’ve hooked the pixelboard up to an IR Rangefinder so it could light up based on distance of an object infront of the sensor.
XBee Configuration
Saturday, May 24, 2008
One of the devices I’m most excited about lately is the MaxStream XBee. The problem with this seemingly innocuous little device is that it wouldn’t behave the way any other tutorial I found said it would. I’ve been working through three different sources of information on the XBee. The first was the source was the always helpful Arduino Forum. Then there’s the excellent article on the Arduino Playground by M. Yarza — though this would have been more helpful initially had I spotted the next page links at the bottom of each page. The third resource is this fantastic book put out by O’Reilly called Making Things Talk. (I’d hazard to think that most people getting involved with the Arduino and XBee will be coming into it from this book and Make magazine)
The first issue I had was working out how to configure the XBee module. The Arduino serial interface doesn’t appear to like to send characters as they’re typed, and requires a line break before it executes. This proves to be an issue with the Command Mode in the XBee. The workaround is to move into a terminal application that does support direct TTY. On a Windows machine PuTTY should do the trick, or Screen on the Mac OS. I’m using a Mac, but the PC should be a matter of pointing the terminal at the COM port associated with the USB-Serial adaptor that you’re using. On a Mac you’d point this at /dev/tty.usbserial[identifier].
The Arduino can act as a USB-Serial adapter if you like. Just remove the ATMega168 chip and communicate directly through the TX/RX ports.
To execute Screen type:
screen /dev/tty.usbserial-A4001uBD 9600
Replace the usbserial name with the one that is present on your system. The name should only appear when the USB device is plugged in, otherwise you won’t see anything. The connection speed of 9600 baud is the default connection speed of the XBee radio. If you’ve altered this, call your new baud rate here.
Once you’re in type in:
+++
This enters command mode. Here you can get or set the XBee parameters:
ATID returns 1111.
ATID1234 sets the ID for the XBee to 1234. It should return nothing.
ATID will now return 1234.
ATWR writes these values to the XBee.
ATCN exits command mode if it hasn’t automatically done so by timeout (~10s).
The configuration options go on from there, and they get increasingly complex.
Hopefully that helps others in a simillar situation I found myself in. Soon I’ll post a follow up detailing my setup.
Xbee Thoughts and Ideas
Monday, May 19, 2008
Playing around with the Xbee has led to a number of really interesting thoughts and ideas. Part of me is thinking that some of these ideas are far more interesting than the Solenoid project I’m currently working on. I have to keep reminding myself that I should really finish one thing before starting the next.
I’m still wrapping my head around the Xbee and what it does, and I can tell you what it doesn’t. Its not a bluetooth adapter (you might be looking for a BlueSMiRF radio instead). It operates on the 802.15.4 Zigbee protocol. Essentially it sets up a mesh network.
The node points for the Xbee OEM modules are 30m in radio frequency (RF) or 100m line of sight. The Xbee Pro’s go to 100m RF, and 300m line of sight. Where it gets interesting is the Xbee Pro-XSC at a range of 24 km in RF.
The modules are capable of being configured as a peer to peer, one-to-many, or many-to-many. They can hibernate, just broadcast or receive, and more. The spec sheet is quite impressive. If you send a message from one node, it could repeat till it finds its destination in the network. Imagine this on a scale of ~20 km node points.
Lets say we build a telemetry device and outfit it on a vehicle. That device could consist of a couple sensors, say a Hall Effect sensor typical in bicycle computers and ABMs on cars, and a compass module (I’ll explain my reasoning behind this over a GPS later). Other possibilities could include a heart rate monitor, air quality sensors, battery power. I’d love to integrate my heart rate monitor into the mix. A USB stick could connect to the Arduino (I’m loving the new Nano form factor) and act as a data-logger. Finally a localized Xbee controller would sit dormant on the device. As the vehicle moves an onboard timer records the data to a timestamped string:
20080519 20:55:59,4.5204,30
These fields would translate back to “Date/Time, Radians, RPM”. Over specified intervals new data would be recorded and stored locally. When the device comes within range of a broadcast node it would awake out of hibernation and deliver the data into the mesh network. A receiver station collects the data from the mesh and sends a confirmation signal. The broadcaster deletes the store of data and starts over, sending the local Xbee into hibernation mode again.
The data is then processed by the receiving station, plotted onto a mapping API, cross-referenced against other broadcasting modules, etc.
I’m going to play devil’s advocate on myself here:
Why a compass module over a GPS? Would that not deliver more accurate data? From what I’ve read, a compass module should provide a far lower drain on the power supply. It would also operate in situations where no sky visibility is provided. The form factor is much smaller, and no antenna would be required. The disadvantage is you need to know the precise starting point (found via GPS no less), and mounting considerations would apply.
The interesting thing is that I have all of the components working in isolation. Its just the small matter of getting everything to play as a team. Then moving it out into the field for some real world tests. Right now these are just some thoughts, but I can’t explain how exciting this little device is.