Monthly Archives: January 2020

New products: 24V 37D Metal Gearmotors

via Pololu Blog

We are excited to share that we have expanded our line of 37D Metal Gearmotors to include 24 V options. These brushed DC gearmotors are the largest and most powerful we carry, measuring 37 mm (1.46″) in diameter. They are available in gear ratios ranging from 6.3:1 to 150:1 and with or without integrated 64 CPR quadrature encoders on the motor shafts. The 12 V and 24 V motors offer approximately the same performance at their respective nominal voltages, with the 24 V motor drawing half the current of the 12 V motor. The table below summarizes all of the options we now have available. Please see our newest revision of the 37D metal gearmotor datasheet (2MB pdf) for the full specifications and performance graphs for all the options.

Rated
Voltage
Stall
Current
No-Load
Current
Gear Ratio No-Load Speed
(RPM)
Extrapolated
Stall Torque
Max Power
(W)


Without Encoder


With Encoder
(kg ⋅ cm) (oz ⋅ in)
12 V 5.5 A 0.2 A 1:1 (no gearbox) 10,000 0.5 7 item #4750
6.3:1 1600 3.0 42 12 item #4747 item #4757
10:1 1000 4.9 68 12 item #4748 item #4758
19:1 530 8.5 120 12 item #4741 item #4751
30:1 330 14 190 12 item #4742 item #4752
50:1 200 21 290 10 item #4743 item #4753
70:1 150 27 380 10* item #4744 item #4754
100:1 100 34 470 8* item #4745 item #4755
131:1 76 45 630 6* item #4746 item #4756
150:1 67 49 680 6* item #2829 item #2828
24 V 3 A 0.1 A 1:1 (no gearbox) 10,000 0.55 8 item #4690
6.3:1 1600 3.5 49 14 item #4688 item #4698
10:1 1000 5.5 76 14 item #4689 item #4699
19:1 530 9.5 130 13 item #4681 item #4691
30:1 330 15 210 13 item #4682 item #4692
50:1 200 23 320 12 item #4683 item #4693
70:1 140 31 430 10* item #4684 item #4694
100:1 100 39 540 8* item #4685 item #4695
131:1 79 47 650 6* item #4686 item #4696
150:1 68 56 780 6* item #4687 item #4697
* Output power for these units is constrained by gearbox load limits; spec provided is output power at max recommended load of 10 kg⋅cm.

Note: The listed stall torques and currents are theoretical extrapolations; units will typically stall well before these points as the motors heat up. Stalling or overloading gearmotors can greatly decrease their lifetimes and even result in immediate damage. The recommended upper limit for continuously applied loads is 10 kg-cm (150 oz-in), and the recommended upper limit for instantaneous torque is 25 kg-cm (350 oz-in). Stalls can also result in rapid (potentially on the order of seconds) thermal damage to the motor windings and brushes; a general recommendation for brushed DC motor operation is 25% or less of the stall current.

24-bit stereo audio DAC for Raspberry Pi

via Dangerous Prototypes

Dilshan Jayakody has published a new build:

This project is about 24-bit stereo DAC, which we build for Raspberry Pi boards. This R-2R ladder DAC is developing around Intel / Altera EPM240T100C5N CPLD.
We developed this module after review the PT8211 DAC, which we tested a few months ago. Compare with PT8211 DAC, this module is capable to provide high-quality audio output with Raspbian OS.

See project details on Jayakody’s blog. Project files are available on GitHub.

Simple VU-meter circuit

via Dangerous Prototypes

VU-meter circuit built on a breadboard using transistors, diodes, resistors, and LEDs @ Build Electronic Circuits:

It’s basically a simple display for showing a value. It’s originally for showing signal level in audio circuits, but there’s no reason you can’t use it to show temperature, rain intensity, light level, or whatever other value you are measuring.

Check out the video after the break.

Designing an extremely realistic animatronic heart with Arduino

via Arduino Blog

In his latest video, Will Cogley has created an animatronic heart so realistic that you might wonder if it’s the actual thing. 

The device is made out of molded silicon with fake blood poured on top to enhance the effect, and inside a trio of servo motors push the lower and upper sections of the prop out in a very lifelike pattern. 

Control is via an Arduino Micro along with an I2C servo controller, while power is provided by an external tether. A potentiometer on the back is used to vary heartbeat speed. 

He also made a simpler — and less potentially terrifying — version with a cloth exterior. This one is battery-operated and runs on a motor and linkage system, perhaps making it good for a nice portable joke!

Fake cases — make sure yours is the real deal

via Raspberry Pi

We’ve had some reports of people finding cases that pretend to be official Raspberry Pi products online — these are fakes, they’re violating our trademark, they’re not made very well, and they’re costing you and us money that would otherwise go to fund the Raspberry Pi Foundation’s charitable work. (Reminder, for those who are new to this stuff: we’re a not-for-profit, which means that every penny we makes goes to support our work in education, and that none of us gets to own a yacht.)

Making sure your accessories are legit

If you want to be certain that the Raspberry Pi accessories you buy are the real thing, make sure you’re purchasing from one of our Authorised Resellers: if you buy via our website, you’ll automatically be directed to the Authorised Resellers in your region. Lots of other vendors also sell the official case, so if you’re wondering whether yours is the real thing, we’ve found there are some easy ways to tell the difference.

A wellwisher sent us one of the fake cases (elegantly photographed by Fiacre above), which we passed around the office with a great deal of wincing, imagining what you guys might say if you got your hands on one and thought we’d made it. They’re really not very nice; the moulding’s awful, the fit’s bad, the colour’s off, and we’d be embarrassed if we had made something like this ourselves.

Asking the experts

We thought we’d ask the good people at T-Zero, who did all the work on the tooling and injection moulding for the real case (which is a considerably harder job than we’d imagined at first — you can read about the very bumpy road we had before finding T-Zero, who are amazing partners, in this post from days of yore), why the fake cases look so hideous. Simon Oliver, Grand Poobah of Plastics, wrote back:

Basically, what you are witnessing is very cheaply and quickly made tooling. The flash is just poor toolmaking. The rounded edges are due to the toolmaking method of milling everything, which is quick and cheap, but you can’t get definition of sharp corners because you have to have a radius in places. I have tried to explain it below, and you have to think in reverse for the tool.

Milling artifacts

Can you imagine how many electrodes are needed for the logo? The leaves around the top have to be laser-cut into an electrode to get the definition. See screen grabs of the tool and moulding — look how many sharp corners there are!

CAD representations of logo and tool

Reverse-engineering by digitising existing components in a CAD will also loose definition, particularly in sharp corners, as the moulding process will form a small radius even if the tool is a sharp corner.

Plastic shrinks away from a 90 degree corner, leaving a smallish radius in any case. So your data from digitising will have a radius, and then [the producers] compound it by milling the lot.

Finally, the colour is off! It took ages to get your Raspberry Pi red correct. A lot of suppliers can’t repeat it; the current supplier had five attempts!

Thanks, Simon; and to everybody reading this, we hope it arms you with the confidence to make sure you’re buying a genuine product!

FYI

Before panic ensues, please note: we love third-party cases designed for Raspberry Pi. So much so that we sell a few of them in our store here in Cambridge.

The internet is full of innovative cases you can purchase, as well as wonderful 3D-printable alternatives you can make yourself, and as long as they aren’t breaking any trademark rules — using our logo, copying the work of others, pretending to be official when they’re not — that’s great!

If you’ve designed a case for any of the Raspberry Pi models, share it with us in the comments below, as we’d love to see your work. And if you see a case, or any other Raspberry Pi accessory, for sale that you think is breaking trademark rules or attempting to imitate our official products, please let us know.

The post Fake cases — make sure yours is the real deal appeared first on Raspberry Pi.

Friday Product Post: Drop Those pHAT Beats

via SparkFun: Commerce Blog

Hello and welcome, everyone! We have a few new products to show off this week, starting with our second version of the Qwiic pHAT for Raspberry Pi, which has been updated to be much more accommodating for robotics and high-power projects! Following that is a new version of the NVIDIA Jetson Nano, now with two MIPI-CSI camera connectors! Rounding out the week is an improved version of the SparkFun moto:bit Carrier Board for micro:bit, and a new Op-Amp IC.

New and improved Qwiic pHAT for your Raspberry Pi!

SparkFun Qwiic pHAT V2.0 for Raspberry Pi

SparkFun Qwiic pHAT V2.0 for Raspberry Pi

DEV-15945
$5.95

The SparkFun Qwiic pHAT V2.0 for Raspberry Pi is the quickest and easiest way to enter into SparkFun’s Qwiic ecosystem while still using that Raspberry Pi you’ve come to know and love. The Qwiic pHAT connects the I2C bus (GND, 3.3V, SDA, and SCL) on your Raspberry Pi to an array of Qwiic connectors on the HAT. Since the Qwiic system allows for daisy-chaining boards with different addresses, you can stack as many sensors as you’d like, to create a tower of sensing power!


NVIDIA Jetson Nano Developer Kit (V3)

NVIDIA Jetson Nano Developer Kit (V3)

DEV-16271
$99.00

The latest addition the Jetson family, the NVIDIA® Jetson Nano™ Developer Kit (V3) delivers the performance to run modern AI workloads in a small form factor, all while being both power-efficient (consuming as little as 5 Watts) and low cost. Developers, learners and makers can run AI frameworks and models for applications like image classification, object detection, segmentation and speech processing. The developer kit can be powered by micro-USB and comes with extensive I/Os, ranging from GPIO to CSI. This makes it simple for developers to connect a diverse set of new sensors to enable a variety of AI applications. This version of the Jetson Nano Developer Kit comes equipped with two MIPI-CSI camera connectors, which enables algorithms that perform stereo vision.


SparkFun moto:bit - micro:bit Carrier Board (Qwiic)

SparkFun moto:bit - micro:bit Carrier Board (Qwiic)

DEV-15713
$15.95

The SparkFun moto:bit is a fully loaded "carrier" board for the micro:bit that, when combined with the micro:bit, provides you with a fully functional robotics platform. The moto:bit offers a simple, beginner-friendly robotics controller capable of operating a basic robotics chassis. Onboard each moto:bit are multiple I/O pins, as well as a vertical Qwiic connector capable of hooking up servos, sensors and other circuits. At the flip of the switch you can get your micro:bit moving!


Op-Amp - AS358P (Through-Hole)

Op-Amp - AS358P (Through-Hole)

COM-15946
$0.95

The AS358P is a great, easy-to-use, dual-channel Op-amp. Op-amps have so many applications we figured we should probably carry at least one in a DIP package. AS358P applications include transducer amplifiers, DC gain blocks and all the conventional op-amp circuits.


That's it for this week! As always, we can't wait to see what you make! Shoot us a tweet @sparkfun, or let us know on Instagram or Facebook. We’d love to see what projects you’ve made!

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