Tech Toys – Mark Foster's Blog

TreeBot

For Christmas 2011 Pictometry had a holiday “Throwdown” challenge. Each department was given box of miscellaneous items that had to be incorporated into some sort of creation. The box was handed off from one engineer to the next. Everyone was too busy. Finally, with two days left before the judging, it was time to take action. With much help from my fellow engineers I built TreeBot, a remote control Christmas Tree with all the trimmings and wireless video for remote operation.

It consists of my old Duratrax Evader RC car with a Christmas Tree mounted to it, Christmas lights on a power inverter, an iPod Shuffle playing Christmas tunes on an amplified speaker and a 2.4 Ghz video transmitter for remote operation. It is decorated with various items we had to use in our creation. We came in second place behind Finance who did a Christmas Carol play using the items as props but I feel it was a good entry representative of engineering given the time constraints.

I took some pictures of TreeBot as I took it apart in case we decide to build something similar next year:

TreeBot

We used a cheap amplified speaker and an iPod Shuffle loaded with Christmas music to give TreeBot a voice.

A 2.4 Ghz video transmitter was used to transmit TreeBot’s perspective to a receiver wired to an old analog video monitor another engineer donated to the cause.

If I were to do it again I would use a wider angle lens for the video camera. Navigating around corners was particularly difficult because of the narrow field of view.

We made the face out of materials provided. The eyes are made from little sticky foam beads shaped into balls and the mouth is a strand of foam peanuts.

TreeBot was lit up using a standard strand of incandescent Christmas lights (provided) using a cheap power inverter on a 3000mAh 3S LiPo Battery pack.

Presents were secured to the tree using zip ties. Nylon zip ties were used extensively throughout TreeBot.

A piece of wood was placed into each of suspension points to keep the car from sitting on the ground under the weight of the Christmas Tree.

The skirt of TreeBot consisted of two pieces of cardboard from the box we were given cut into two half circles and then stapled together to form a semi-cone. It was covered with wrapping paper and garland was zip tied around the edge. The skirt was then zip tied to the Christmas Tree stand.

The stand that came with the Christmas Tree was zip tied to the car’s frame.

Bolt’s were used as a standoff to level the Christmas Tree stand on the car. Zip ties were again employed to secure the Christmas Tree stand to the bolt heads.

It was not terribly shocking to find that the cheap power inverter wasn’t putting out the advertised voltage even though our input voltage met specifications. Regardless, it was enough to power a strand of Christmas lights.

This is the car frame after everything was removed.

The car has been returned to its former self.

April 1, 2012

Review: Herbie the Mousebot Kit by Solarbotics

I wanted a quick, easy to build robot kit to get back into electronics and robotics. I ask for a Herbie the Mouse Bot for Christmas and sure enough I got one. It was a fun kit to build and went together in a little over an hour.

You start off with a PC board…

… and a handful of components…

You break apart the PC board which serves as a PC board and a body for the mouse which, is pretty cool.

The PC boards join together via several solder joints. Tape is used to keep everything together until you are done soldering. A smaller board that holds the 9 volt battery connector helps keep the three main sides together. By the time you are done soldering all the joints it is a pretty sturdy little robot.

The whiskers and tail activate a relay when bumped so the mouse will backup to avoid getting stuck. I taped the relay down while I soldered it in.

Herbie with the photo diode “eyes” installed….

Herbie just about finished…

Herbie is an interesting robot because it uses a simple analog IC, the LM386, to do something you might think requires a much more complicated digital circuit or micro-controller/processor:

http://downloads.solarbotics.net/PDF/Solarbotics_Herbie_the_Mousebot_Instruction.pdf

We don’t have much open bare floor in the house and it moves quite fast so it was a bit of a challenge to keep it under control without hitting too much:

The Herbie Kit is well engineered and fun to assemble. I give it five stars and recommend it as a good first robot kit.

March 19, 2009

Review: RC Wall Climber/Clamber Remote Control Mini Car (Updated)

RC Wall Climber/Clamber Remote Control Mini Car

Update: Warning

I have received at least one report of a non-working car and the manufacturer has does not seem to have a web site that I can find to get a replacement. I have downgraded my rating to 2 stars accordingly. If you buy one of these make sure you get it from some place you can return it if it doesn’t work.

NeweggMall.com recently sent me an e-mail pushing a wall climbing RC car called the Clamber!!! Master-Hand. It is actually listed under RC Wall Climber Remote Control Mini Car but the name on the box is “Clamber!!! Master-Hand” by Top Race R/C Series. Although similar, this is not the same as the Spinmaster Air Hogs Zero Gravity Micro Cars, which are a bit more expensive. It was cheap and cool enough looking that I naturally felt compelled to give it a try.

How it works

If you are not familiar with these, they have a vacuum inside that holds them to the wall. The four outer visible wheels are actually fake and just look nice. There are two inner wheels that are not visible (unless you flip it over) that sit against the wall and propel the car.

The switch on the back has three different modes: off, on without vacuum, and on with the vacuum. This way if you just want to run it on the floor you don’t have to turn on the vacuum and waste your charge.

The underside has two strips of fabric that sit against the wall to help maintain the vacuum. There are two intake holes on the bottom and 4 slits in the windows on top for the air output.

The car itself looks pretty cool although the fake tires are a little less than authentic. It comes in three colors: Red, Black, and Blue.

Performance

The car does not go too fast but fast enough. It drives similar to a tank because it is actually only using two wheels. To steer, it changes the speed of the wheel on the appropriate side. While you are driving the turn radius is not precise and tends to be a bit large. When you are stopped it will turn on a dime.

As power starts to run down, the vacuum does not hold the car as tightly to the wall as a full charge so sometimes the drives wheels will start to slip and you have to turn around and go in a different direction to get moving again.

Run time on the wall is about 7 minutes although performance slopes off and the car will start loosing its traction around 4 minutes. Even after 7 minutes the vacuum was still strong enough to keep the car on the wall. I didn’t time it but I am guessing run time on the floor without the vacuum on would be quite a bit longer. When you get close to 8 minutes the power will cut off before the battery is drained too far. It uses a built in Lithium-Polymer battery which is probably why a charge last as long as it does for something so light. Charge time is about 10 minutes.

Here are some pros and cons:

Pros

Pretty good amount of drive time per charge (about 7 minutes)
Only a 10 minute charge
Can rotate on a dime while stopped
Fun!

Cons

It will get stuck on even flat, clean surfaces occasionally after the battery has run down a bit.
The turn radius between running and when it is stopped is quite different. When it is stop it turns on a dime. When it is running it has a very wide turn radius in some cases.
IR controller does not perform well under strong light.

Conclusion

Overall I rate the wall climber 3 out of 5 stars. I would give it more stars if the steering were a bit more consistent and it didn’t get “stuck” as often. Overall it was pretty fun but I would say the Microfly is a bit more entertaining just because for about the same price or less, it flies around and that is hard to beat in my opinion.

Images

RC Wall Climber Clamber Remote Control Mini Car

RC Wall Climber/Clamber Remote Control Mini Car

RC Wall Climber/Clamber Remote Control Mini Car Charging

Video

January 24, 2009

Review: Senario NRG MicroFly RC Hovering UFO

In a previous post I talked about the Senario Alien Microfly a bit and in this post I will provide a full review. I gave a few units to some of my family for Christmas so I have flight reports from them as well.

The Senario Alien Microfly kit comes with a transmitter and the Microfly itself. The transmitter takes 6 “AA” batteries and also serves as the charger for the Microfly. It is pretty small (see the pictures below) and a lot of fun to fly around the house or office.

I put in many, many flights. Each flight is about 5 minutes with a 15-20 charge time. The cats gave it a few taste tests but mostly they like to just stalk it as it flies around the living room. 😉 I bought 5 of these for myself and my family for Christmas and all of them worked out of the box. Here is a list of pros/cons:

Pros

It is simple to fly. There is only one control to make it go up or down so you don’t need a lot of experience.
Cheap. You will probably find it for $25 or less.
Durable. You can’t sit or step on it (it is mostly just foam board) but mine has been through many crashes and even survived a few taste tests by the cats.
The flight time is about 5 minutes which I think is pretty good for something so small.