Got my Monoprice Select Mini 3D Printer Today

There are lots of great reviews of this one on you to youtube. I’ve been dying to get into 3D printing for quite some time and I decided to take the plunge with this one. The most appealing thing to me was the price 🙂

Is it possible to get a reasonably good printer for $200?!

Well, I was foaming at the mouth in excitement to get this — two months later I’ve barely touched it. I’ve actually found a couple of better solutions than the parts I was going to print, and I’ve been keeping busy with other things. I hope I’ll use it more soon…

 

Buying resistors

If you’re going to purchase resistors, don’t get these blue ones. The color bands that show the values don’t show up well enough against the blue background. They’re fine if you only use one value for instance, but if you regularly need to read different values, at least for me, I got a refund because they were so hard to read.

Get the ‘normal’ ones (used to be standard until, like too many things, manufacturers got cheap and started to use lesser quality) with a brown background

And watch out for the ones that have extremely thin leads. All of them that I’ve purchased from China have had very thin leads that are difficult to handle and bend way too easily.

I found resistors from a US supplier that have the brown background and the ‘normal’ fatter leads at a very good price. Here is their ebay  store: http://stores.ebay.com/E-Projects-Electronics

Off course you can get them from other sources, too. I found them for sure at www.newark.com and www.microcenter.com

All about the L298N H-bridge motor controller module

Oh boy, was I confused about this module at first! I found a fair amount of bits and pieces about it, but could not find the complete info that I was looking for. So I decided to create this tutorial for others who want to understand it better. I’m not an expert, but I have figured it out well enough to make what I think is a very clear and complete basic ‘primer’ on this device. Whether it’s right for your project is up to you to determine, but here’s info about the module itself, and especially about the mysterious jumpers (at least they were the biggest mystery to me).

What is it?

This module is a very inexpensive and convenient package based on the L298 dual full-bridge rectifier chip made by ST Microelectronics. It can be used to drive speed and direction for one servo or two standard DC motors, and drive other inductive loads like relays and solenoids. It can be controlled by microcontrollers like the Arduino.

Here is the description of the chip (not the module) from ST: The L298 is an integrated monolithic circuit in a 15-lead Multiwatt and PowerSO20 packages. It is a high voltage, high current dual full-bridge driver designed to accept standard TTL logic levels and drive inductive loads such as relays, solenoids, DC and stepping motors.

You can see the data sheet on their website here: http://www.st.com/en/motor-drivers/l298.html .

You could just purchase the chip and component parts and wire up your own parts, but this complete module is probably cheaper than the combined parts, and it’s certainly more convenient. As of January, 2017, the modules are selling on ebay for under $2.00! At this price they’re from China of course, but you can purchase them at higher prices in the United States if you can’t wait for the long shipping times from China.

I’ve read in forums that the L298 chip is about 15 or 20 years old, so there are better(?) chips available now. People seem to like the Pololu A4988 https://www.pololu.com/product/1182 .  Stepper motor current limiting is apparently one of the big improvements, but none of the current-limiting chips come in this neat module format that I’m aware of. So this L298N module is fun and handy, certainly great for testing and little projects, but be careful if you need current-limiting features when driving stepper motors.

The module components

Here’s where I was the most confused. If you look at the auctions on Ebay you get the typical Chinese-translated-to-English descriptions that are neither complete nor understandable. And searching for other resources on the internet or YouTube results in some great information, I was not able to find any one source that was all-inclusive like I’m hoping this one is (for a basic primer anyway).

…More coming soon…

My new CD is available now!

cd-art-tear-downs

cauldron                    junction box

Learn About Halloween
Animatronics!

And other animated gadgets and props!

Get 17 videos and close-up photos!

CD mailed to you — or download right now!

Click here to see the complete ‘Witch’s Legs in Cauldron’ video on youtube

Click Here to Learn More and Order!

 

Ways to Lift Lids (as in opening coffin lids for Halloween props)

I thought I would offer some ideas on different ways to open box lids. My main motivation has been finding a good way for lifting the lid of small Halloween coffin props, but the techniques can be used for many other applications as well.

I love to play around making these things as a hobby, but I need to make smaller versions of these because I don’t have enough room for full-sized ones. Here’s an example of a nice full-sized one by MrTmartindale on YouTube.

Seeing as I was recently playing around with pulleys I thought I would start with probably the most basic way to lift a lid — with a string!

open2a            open3a

There are a lot of potential problems with this arrangement:

It’s visible.

You need to reverse the polarity on the motor for up and down directions.

It takes up a lot of space.

It needs a lot of parts: string, string pulley, pulley support, motor, motor pulley, motor mount, and some way to reverse the motor direction.

More ideas and videos coming soon…