That might as well be the name of my “Wastebin Project” category. I haven’t done a Wastebin Project in a while so I’m shaking off the dust on this blog category today. This category is for those small random projects that only last for a day. They usually happen without proper thoughtful prototyping. It’s just about getting the creative juices flowing, experimenting, and having fun thinking on the fly.

Anyways, today I wanted to try something I’ve been meaning to do for a while, and that is try to create the smallest mobile robot I can. I also wanted to challenge myself to see what I could come up with in an hour.

I’ve done a couple of mobile robots before. My first robot was “Frank” who won the hearts of many. My second robot, “Greg”, was what I liked to call the Mobile Billboard because it was a rectangular bot with an LCD strapped to it. With my PCB designs that I’ve been posting about for the past little while, I can get a mobile robot to get into an even smaller form. Spoiler: It doesn’t work out, but seeing what doesn’t work along the way was interesting to me.IMG_20140924_154601This was it at the end of the project. If things did work out, I’d swap out the jumper wires for shorter soldered wires to neaten things up. What really was the final nail in the coffin was a wire between the 9v battery holder and my AMS1117 Voltage Regulator Board broke. But that was just one nail, among a few others.

The big thing I learned was that the servo library doesn’t work with the Attiny85 microcontroller because the servo library relies on 16-bit timers while the Attiny85 has 8-bit timers. I’ll have to look into it, but upon some light research it looks like it’s possible. After I realized that, I swapped out my Attiny85 Breakout Board with my Atmega328p Breakout Board. I got the servos rolling, but there was no control or logic behind it.

I wanted to try using a photoresistor instead of the ultrasonic sensor to be the eyes of the bot. I didn’t test the photoresistor so I couldn’t calibrate it. I was just guessing values but none of them worked so I don’t even know if the photoresistor was working at all. I still have the circuit so I can play around with it.

IMG_20140924_155017I kept the chassis because I want to try this again. This is how I always make my chassis but it’s a lot smaller compared to my previous robots.
IMG_20140924_155031This is the photo resistor circuit, as well as the power supply outputs (the headers) for the servos. I’ll play around with the photoresistor and maybe this could be back again in round two.

Thanks for reading! I’m still working out plans for my next project. It should be a light show… Stay tuned!

Fun with hot glue

I was bored today (as I am everyday) so I decided to try something I saw on Instructables a long while ago. People were using hot glue to diffuse the light from LEDs and to make small shapes.

IMG_1411My focus of this experiment was to see how the light looks on different shapes made of hot glue, mainly strings. The light didn’t really get very far.
IMG_1412The glue is not clear when it is dry so it makes for a good diffuser for the clear lens LEDs. I couldn’t really get the shapes I was hoping for since the light didn’t go very far down the hot glue string.
IMG_1410I was hoping to make a project out of this if the result was better but I don’t think I will bother. Oh well, at least I tried. It’s also great that the hot glue snaps off of the LED with no residue or excess glue left behind so no LEDs were harmed in this experiment.

I’ve seen other people have better luck, so if you’ve tried this yourself, share your results in the comments!

Charlieplexed 4×4 Matrix w/Attiny85

Between the light show and EERef, I haven’t had any time to really think about how to use these Attiny85’s I recently bought. After some image searching for inspiration, I settled on a 4×4 matrix using the charlieplexing technique.

IMG_1164Since the final thing would be soldered, I really wanted to hammer out the details on paper to make sure I got things right the first time. I did some sketching to make sure the schematic makes sense… As an experiment project like this, I didn’t bother prototyping on a breadboard so my plans had to be right. I sketched out the perfboard layout on some grid paper (not pictured) which is always a massive help.
Soldering went perfectly fine. I’m really happy with it.IMG_1163I manually tested each LED by connecting a hot and ground wire to the appropriate pins on the socket, and it works as it should. I ordered some headers and terminal blocks last night so it should have a way to connect power by the end of the week. I did some simple tests with the Attiny85 (powered by poking wires at it) and that worked as well. Programming will continue on while I wait for the terminal block. A final update will be posted when it’s all done. Thanks for reading!

Homing a motor with a photoresistor

I did some experimenting today with a photoresistor. A few days ago, I saw a project where someone used a photoresistor as a sensor when someone walked into a room or something like that, by pointing an LED at it and then waiting until the light was interrupted by someone in the way. I thought I could use that same concept with a servo motor.

The original plan was to build something like the Frog Hopper tower I built a while back. It would actually have “eyes” this time, as I would have mounted four sensors and four LEDs up the tower to track where the car is. After a couple of hours of not getting cardboard to cooperate with me, I gave up and quickly came up with a new plan to still play around with the concept.

If you know me, you know I’m a huge amusement park fan. Half of my fun at amusement parks are just watching the rides and picking out parts of them to figure out how it all works. IMG_20130604_114029If you know me really well, you’d know that my favorite ride is Sledge Hammer at Canada’s Wonderland. A lot of people knock it because it’s not very thrilling, but I’ve been so fascinated by it since it opened in 2003. In this picture, I’ve drawn a yellow circle pointing out a green proximity sensor, lined up with a thin piece of metal attached to the gondola, or the seats of the ride. As the ride cycle is ending, the gondolas slowly spin around trying to line up the piece of metal with the proximity sensor. I find it very interesting to watch, because most of the time it will pass by it and slowly reverse back to line up with it.
IMG_1057Anyways, this is what I set up. The button on the breadboard is used to tell the system to home the motor if the motor is running, or to restart the motor if the motor is stopped.IMG_1058 The continuous rotation servo motor has a piece of cardboard attached to it. The photoresistor sits on the servo motor and has the red LED shining on it whenever the cardboard rotates out of the way. Check out the video to see how it works:

Wastebin Project – Ghetto Mountain (PS. I Love Adafruit)

This is another Wastebin Project (electronics experiment). It’s a cardboard cutout of Wonder Mountain at Canada’s Wonderland, with some LEDs pointed at it. It’s inspired by their 3D projection mapping show, Starlight Spectacular.
IMG_1010The original plan was to have different layers of the mountain separated far enough to put LEDs in between the layers to light up each layer. It didn’t look very good so I ended up just gluing all of the layers together which still left me with a pretty nifty cardboard cutout of the mountain. I still wanted to try lighting it up so I just put some RGB LEDs on a breadboard and bent them to try and light up sections of the mountain. The clear lens RGB LEDs would have been perfect for that but each color doesn’t shine at the same position so that didn’t work. At least I got to try my new diffused RGB LEDs.

It was fun to have a go at this, actually funny that I posted that video about half an hour before discovering my light show projects were featured on the Adafruit blog for Arduino Day. It really means a lot to me. Thank you Adafruit!

PS. I really need to fix up the Featured Project pages. Some of them may be (and have been) transferred to their own separate site. It’s been done for EERef and the Arduino Temperature/Humidity Monitor.

Full-Wave Rectifier – A short revisit

A couple weeks back, I did a tutorial on full-wave rectifiers. I picked up a rectifier bridge IC just for fun. Let’s see how it worked out.

IMG_0958If you go back to the tutorial, we got the same output reading directly from the rectifier.
IMG_0959I was interested in picking one of these up because, if I ever needed a voltage up to 18v, the circuit is smaller so I would actually consider using it… Though that case would only be if I needed that high a voltage, and if I didn’t have another supply handy for it.IMG_0960The chip is labeled nicely so that you don’t need the datasheet for anything.

Thanks for reading!

Wastebin project from June 2013

Just to prove that the Wastebin Project I started off with wasn’t just a one off thing, I thought I’d make a post about a wastebin project I made just before I started this blog.

This creation came right after I first completed my PLC Trainer project. I wanted to do something involving motion in an Arduino project so I ended up with that arm thing. The only projects I had done up to that date were the light shows that didn’t involve servos yet. After playing around with the servos and cardboard, I ended up with this:

Once I was convinced servos could play a part in my light shows, I went on to create my first show set to music.

You can see the rest of the story through the LED Light Show posts. Check out the categories in the sidebar.

A few notes to wrap things up… I’ve put up a new Links page that list suppliers and tutorials I’ve used for my projects. I also have a package coming sometime this week from Dipmicro. I’m still working out the details of the next project but I’ll have some brainstorming notes up soon. Stay tuned!