Deftaudio is at it again! We recently covered their fidget spinner Eurorack module, and now they’ve turned the concept on its head! A powerful stepper motor inside this module has a shaft coupler attached to it, so you can get creative and use it to turn knobs automatically on any other module in your rack. Or you could use it as a display piece, and have it spin an LED board in response to the music you’re making.
The MotorPot can be controlled via MIDI through the standard Eurorack TRS-A/B cables or via USB as a MIDI class device. It’s also possible to rotate it with a control and gate voltage like traditional analog synthesizers typically use.
Using a rotating disc and shaft, the MotorPot controls a slide pot on the rack above
The example shown above is very over-the-top and we think it’s great! Controlling a linear potentiometer with a reciprocating drive is just ridiculous enough to be awesome. The particular stepper motor used has some power behind it, and Deftaudio recommends giving it a separate 2A supply if it’s going to be used in a way that draws a lot of power. Most Eurorack power supplies are not quite beefy enough to handle the load that this module creates, so double-check what your rack has before installation.
The module is available both as a DIY kit and as a fully assembled unit, ready to go. If building the DIY option, make sure to get a Teensy 4.0, either from Deftaudio pre-programmed or from another vendor and then program it yourself. Give your rack some personality with this quirky motorized module!
I love playing with robotics — what hacker doesn’t? Servos, stepper motors, linear actuators, pistons… there are so many ways to move things around. It’s uncommon to see a miniature precision stepper-based linear actuator, though! Actuators this small can be very handy for a number of different hobbies and projects.
This custom-built linear actuator board would be an excellent match for people who are into modelling — whether it’s model train kits or model cities, a little movement can bring any design like that to life! And it’s small enough to easily hide away, with enough range of motion and torque to accomplish quite a lot of movement. It’s also fully compatible with many open-source software libraries for control, like the Arduino Stepper library. This makes it quite simple to set up and program for your application.
Because it’s based on a stepper motor paired with a dedicated stepper driver chip and a fine-pitch threaded rod, you can get exact movements that are repeatable. This makes it a good candidate for making small X-Y tables or other fixtures that can be used for CNC machines. Another good application would be making interactive toys, or adding additional features to RC cars/robots!
The seller Questwise Ventures seems quite keen on making miniature boards for all sorts of things, so be sure to check out the rest of their shop. But first, check out the demonstration video below to get an idea of just how small and precise the mechanism is!
If you sell PCBs on Tindie, you’ve perhaps designed a board to be hand built, then eventually set it up as a PCBA for assembly elsewhere when the volume and maturity justifies it. I went through this process myself with one of my products. Admittedly, there was a part where I was applying solder paste for assembly which could have been done in a neater and less wasteful manner.
One solution is to use a solder stencil, which in my experience comes with its own set of challenges – including the need to actually design and make. The second solution is to use a dispensing setup that can help you more accurately dispense globs of solder paste than with a manual syringe. Such a device comes with its own set of challenges, often including the need for compressed air. The e.Dispenser from Dan M does things a little differently by precisely displacing solder paste with a servo-driven linear actuator.
I got my hands on one of these units to try out and I’ve been pretty impressed, but read on to see my thoughts on how the device works!
e.Dispenser Initial Impressions
The system sells for a list price of $149.00 USD, including enough accessories (sans actual solder paste) to get you going. There are also a number of additional options available, including a foot-pedal and on-dispenser device trigger.
The device is made in, and ships from, Mexico. As an American buyer, my first hesitation was that there might be some import duties and/or hassle, however, I’m happy to report that in my case getting it was no trouble whatsoever. It simply showed up at my house in Florida via UPS, 11 days after placing the order. The item was very well packaged in custom-cut foam, which could double as storage apparatus if you’re careful when opening it up.
The device itself was well-made, with a laser-cut housing, and an LCD character display that will be familiar to anyone who has browsed an Arduino projects site for even a few minutes. The reversible USB-C power input was a nice feature, and there’s a 3.5mm jack for accessory connection. Finally, the driving stepper motor is keyed in such a way that it can’t be reversed when plugging it into the controller.
Dispensing Solder Paste
The unit is easy enough to plug in and turn on, and features a menu system driven by two encoders. The left encoder selects the menu option, while the right actually modifies it. When you press the trigger button, settings are saved to the profile you’re working with. When either is pushed in (at any time) the left pushes the piston forward, while the right pulls it back.
To insert solder paste, a coupler is included that lets you push it out of your old tube into the new tube quite elegantly. From there, the machine’s piston can push it out blob-by-blob. This is where things got a little hairy, due to:
I had no idea of the scale needed to push out a component’s worth of paste
My roughly year-old paste, stored in a hot garage wasn’t doing me any favors.
Quite a bit of excess initially dripped out after dispensing, and didn’t get the right amount on my pads to begin with. I contacted Dan M. about my predicament.
Long story short: I was dispensing way too much paste, and, according to Dan, depending on the type of paste you’re using, tiny air bubbles can cause a sort of internal spring effect. He gave me a few suggestions on things to try, and after a bit of tinkering, it worked much better. Also, it might seem obvious to many readers, but pressing down on the board before triggering the paste seems to work better than triggering it mid-air and attempting to dip paste onto the pads.
Dan’s support was prompt and excellent, offering me input and settings to try. That being said, I should have perused the documentation on his website more carefully, especially the page about dot dispensing to get a better sense of scale. I eventually made several prototype boards using the dispenser, which turned out much better than my syringe-only attempts.
After a bit of adjustment, oozing improved significantly
In my testing, I still get some paste extrusion after finishing a job using the dot dispensing mode. If/when I continue to tweak things (and/or buy new solder paste) I suspect this will improve. This adjustability is an excellent feature of this device, and up to 5 setups can be saved to allow you to work with different paste setups and/or scenarios.
External Trigger
As mentioned earlier, there’s a 3.5mm jack into which you can plug a foot pedal, or a trigger that slips over the dispenser tube. Both worked as designed, and I primarily tested the pedal. It’s also easy enough to start the device via the button on the main controller, though using the foot pedal felt natural and helpful once I started using it.
Vacuum Pickup
In addition to outputting solder paste, this device is also capable of picking up components and small ICs using vacuum. As there’s no air compressor involved, the way it does this is by pushing the piston into position, then pulling back to create a vacuum when triggered. I tested this with a few addressable LEDs, and even the Ooberlights circuit board seen above, and it works well.
The fact that it doesn’t need an air compressor is probably the #1 feature that will draw people to this device. The tradeoff here is that the driving stepper motor is on top of the dispensing syringe, which means that the center of mass is well offset from its geometric center. This wasn’t a problem for the limited assembly work that I’ve done with it so far, and I am thrilled to have this as a part of my workbench for prototyping. At the same time, this would likely be problematic if put into constant use over a full production shift.
A fascinating possibility for this device is that it seems to be just begging for people to use it in an automated manner per its external trigger capability. Dan has a guide to setting it up on a 3D printer here, but who knows what other people will (and have) come up with? Notably, the device can dispense other types of paste, opening up possibilities further.
The Verdict
This dispenser is well built and well supported, and it fills the niche between “what am I doing with this squeezy syringe thing” and full offshore production. There’s also the exciting possibility of repurposing a 3D-printer or other robotics assembly to work with this device. If you fall in the category of avid SMD prototyper, then in my humble opinion, it’s absolutely worthy of consideration!
Disclosure
Dan M provided the product at a discounted rate to me for this review. I’ve tried to be fair, open and honest in my appraisal of it, but if you’d like a second opinion (or forty-second opinions), you can check out the device’s customer reviews.
September is in full swing. New York Maker Faire is happening this weekend and the Hackaday Superconference is right around the corner. It also means that it’s time to poke around on the Tindie Flea Market and see what’s going on!
BatteryDuino Battery Shield for Arduino Uno
If you ask how to power an Arduino, there are many correct answers. However, if you want an easy way to do so, this battery shield looks perfect. Simply plug it into the pin on your Uno, insert 3 AAA batteries, and you’re good to go!
DRV8825 Stepper Driver Modules (2 Pack)
Steppers, while more controllable than DC motors, take a bit more finesse to get working. If you’re in need of a stepper driver board, these DRV8825 modules can drive 2.5A per coil, and feature better performance than more common A4988 drivers.
RTC Breakout
Dev boards like the Arduino Uno work well for many purposes, if you want to keep accurate time over more than a few hours, you’ll want to add a separate real-time clock (RTC) module. This device breaks out a DS1307 RTC chip, and includes a coin-cell battery holder and crystal.
5.4 Amp Stepper Motors
So do you need a few steppers to go with the driver listed above? If so, then these three… might not be appropriate given their 5.4 amp rating. Still, at 20 bucks for the lot, they could be a good find for the right project!
Perhaps you’ve never considered making your own huge dot matrix printer, buy you have to admit it looks pretty fun after watching the video below.
For a great head start on building your own, start with the Dotter Arduino Dot Matrix Printer PCB from Nikodem. While this listing is for the PCB alone, the entire assembly uses easily sourced parts. An Arduino Uno drives 3 cheap stepper motors and a servo to pull paper through it and stamp dots with a normal marker. Impressively, it can print paper up to 55cm wide, and a theoretically infinite length.
To build your own, along with populating the PCB, you’ll need to buy the components outlined here, and 3D print quite a few items to form the gantry base. In operation, a Processing sketch sends the controller picture information, allowing it to draw huge prints to your heart’s content!
For another innovative printing solution—and one that also pulls the printing medium into it, albeit on a much smaller scale—be sure to also check out this Pen/Laser Bot controller by Bart Dring that we featured last year!
Motors01CJC by C_J_Cowie via Wikimedia Commons CCA-SA 3.0
If you like to make things—and you’re reading Tindie’s blog so that seems like a fair assumption—at some point you’ll want to make one of your creations move, likely with a motor of some sort. We can help you decide which kind of motor best fits your application. Read on!
DC Motors
DC motors are the simplest rotary motion devices on this list, as movement is started when sufficient voltage is applied between the positive and negative poles. Speed can be controlled by varying this applied voltage, and direction is changed by reversing input polarity. By default, there is no feedback to tell you how fast this type of motor is going. If needed, an encoder can be added to sense speed, and gear reduction can be used to increase output torque at the expense of rotational speed.
While easy to control, they need more current than an Arduino or similar dev board can generally provide. For an easy way to integrate a motor with this type of control, just do a search for Arduino “motor shield” for lots of options, many of which will also work with the other motor types discussed here.
Stepper Motors
Sometimes confused with servo motors, stepper motors operate by energizing certain coils to make a shaft turn one step at a time. This requires more thoughtful control than a simple DC motor, but also gives it the ability to move in a precisely controlled fashion. While there are many uses for this type of device, one notable use is in CNC equipment. For a great illustration of how one of these work, check out the video above of YouTuber Proto G’s 3D-Printed Stepper Motor.
For CNC control options, if you’re interested in driving one in a laser or plotter project, this board looks interesting. It’s meant for use with the Grbl software package, which has become the de facto CNC control standard for Arduino boards. Alternatively, this shield gives a more general Arduino/Grbl implementation, including a connection point for your Z-axis.
Servomotor
Servomotors, or just servos, come in all shapes and sizes, but feature a feedback loop. This means that if there is an error in the motor’s position, the controller knows about it and can take the proper corrective action. Steppers, while generally extremely accurate, don’t have this ability, and if your system somehow misses a step, all further actions from there on out will be inaccurate until it’s re-homed. For many Tindarians, “servo” is synonymous with the hobby servos that are seen in model airplanes and the like. While these work well in many applications, other models are available that can cost thousands of dollars, many of which can rotate continuously with feedback.
Incidentally, you’ve likely heard that you can modify a servo for continuous rotation. After doing this myself, calling these modified motors “servos” is a bit of a misnomer, as there’s no longer any positional feedback. They are simply DC motors in a convenient format with a modicum of speed control. That being said, if you do need positional feedback, then you can add a Mocoder encoder to one of these modded devices, restoring a sense of control to your system!
Of course there are other electro-mechanical options, such as AC motors, solenoids, and variations of the motors listed here. Hopefully this gives you a good place to start if you’re considering building a new robot or other moving device!
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