So now I will start a weekly post of things I've found interesting during the week. Most, but not all, of these items should be tech related. Will try and get one of these posts up every Sunday night/Monday morning.
#1 - Electronic goldmine - I ordered a big box of various surplus parts from the electronic goldmine last week. They have really great prices on a lot of their items, and they were a great way for me to get a large variety of parts for not a lot of money. My "electronics lab" is starting from ground zero, so I don't have a lot of the little odds and ends you need component wise.
The Electronic Goldmine shipped the big box o' parts out to me, and it did not disappoint. I was very happy with the entire order.I even did an Unboxing video of the parts. Most of it is pretty boring, admittedly. In one scene, you can see me take a component out that is surrounded by two pieces of cardboard . I didn't think about what might be in it, and was a little rough trying to separate the two pieces of cardboard from eachother.
I broke the first solar panel, then was much more careful with the second one. It broke too. I was a little clumsy for sure, but the packaging on these things was terrible. After two emails, Ben at the Electronic Goldmine agreed to ship two more solar panels. They arrived quickly and I managed to extract the super-fragile panels safely by cutting the tape open with an exacto knife.
+1 for Electronic Goldmine's customer service. I admitted to having some responsibility in breaking the cells, but they were good enough to replace them anyway. Definitely a company I'll recommend to others and do business with again.
2. Built my first robot this past week using an Arduino Uno, a Tamiya twin-motor gearbox, Tamiya truck tires, a Pololu motor driver, a Pololu round robot chassis and some assorted Meccano parts. The build went relatively well, although it was frustrating at times. I'm not the most mechanical guy in the world, so I ended up doing things the hard way and had to tear the robot apart to put the next piece on several times.
I certainly learned the importance of thinking ahead, and maybe doing a quick sketch of the robot next time before building, I ended up with a terribly ugly contraption, which I just had to name 'ClusterBot'. ClusterBot does function, however so it was an overall success.
I think I will be building my next few robots with a wooden base. Wood is easy to cut and work with and I can drill holes with ease and wherever I want. Plus wood is cheap. The Pololu base was useless for my purposes. The Tamiya twin motor gearbox works surprisingly good for the price-point - $9 as of this post. The motor driver and wheels are great too. Great learning experience.
3. I mounted a HC-SR04 Ultrasonic sensor to the cluster bot and got it working. ClusterBot would go forward until he 'saw' something that was closer than the distance threshold I set. Once that threshold hit, ClusterBot was instructed to keep rotating left until there was no longer an obstacle. After a few hours of typos, using the wrong set of pins on the Arduino mini-breadboard, and making more than my usual fair share of logical errors - ClusterBot was working almost perfectly.
Clusterbot had mounds of jumper wire looped all over his head, however and a few other issues. My daughter ran ClusterBot under a bed, where there were a few tumbleweeds of cat fur hiding out. After ClusterBot plowed into a couple of these, one of the motors almost stopped spinning. I opened it up and removed the cat fur. Put it back together and the gearbox started working perfectly again. I decided right there to go ahead and dismatntle ClusterBox and start over.
I got another robot built, on the same general lines, but much much cleaner. I'll be sharing the new bot with you sometime this week. I got rid of the Pololu round robot frame, and decided to just mount the robot on a Meccano frame instead. This robot is much neater now, and I notice how much taking the weight off and having the robot in balance affects the performance.
4. Ordered several parts from eBay mid-last week. I've already gotten all of them in the mail, even though they had to come all the way from China. I was somewhat leary of ordering from the Chinese sellers on eBay, but I've used several now with good results and super-cheap prices. Compare the HC-SR04 ultrasonic sensor to the Parallax Ping sensor. The Ping sensor supposedly has a little more range than the Chinese knock-offs, but I've found the Chinese Ultrasonic sensors to be very accurate and they have plenty of range for my purpose. The biggest difference is the price - Ebay HC-SR04 is around $4 shipped, while the Parallax Ping sensor is $30 and doesn't include shipping. 8 Chinese Ultrasonics are >>>> than 1 Parallax Ping. I'll have more on the HC-SR04 this week on YouTube and the blog.
5. Found a Robotics website I didn't know about before - Let's Make Robots. A really good site with helpful people in chat and the forums. You can make a collection of other people's postings, robots, pictures, etc. As you browse the site, it's an easy way to hang on to ideas you like for reviewing later. This is probably my favorite bot site I've found so far.
6. On a very sad note, we had to put our 18 year old manx cat, Blackjack, to sleep. My nine-year old daughter is quite the artist in Paint, and made a memorial Speed Paint of our friend. Check it out if you'd like to see her using what I consider to be some very advanced techniques to get the absolute most she can out of Paint.