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Raspberry Pi Accessories

3 Posts authored by: bitscope

This is the first in a series we'll post about using BitScope Blade and the obvious place to start is unboxing and assembling it. Blade is a robust industrial deployment solution for Raspberry Pi. How you assemble it and the ways you can power and mount it will depend on how you want to use it. We'll follow up with more information about the power and software options and cover some new projects you can build with it. Read on here to get started...

 

BitScope Blade is available in three editions; Blade UnoBlade Uno, Blade DuoBlade Duo and Blade QuattroBlade Quattro. Each of them powers and mounts one, two or four Raspberry Pi. They also support a range of peripherals such as Raspberry Pi HATRaspberry Pi HAT, CamerasCameras, DisplayDisplay, BitScopeBitScope and a lot more.

We publish software for Raspberry Pi to make it easy to use and build solutions ranging from single test and measurement or embedded computing systems to full sized compute clusters. Check out this recent post to learn what Blade can do and some typical Blade applications.

 

In the post you're reading now we describe the Blade package and how to assemble it to get started.

 

In the package is the Blade (Uno, Duo or Quattro), a Quick Start Guide, Product Compliance Statement, a Safety Guide and set of screws, spacers and mounting tabs, shown here for Blade Quattro.

BitScope Blade Quattro Package Contents.

There are also 1, 2 or 4 red power shunts, one for each Raspberry Pi. The Raspberry Pi and a power supply are sold separately. Any software that runs on a Raspberry Pi and optional HATs stand-alone may be used with Raspberry Pi and HATs mounted in Blade. Blades also support specialised expansion (HUB Cards) and/or custom hardware via I2C, SPI, UART and GPIO on the underside of each Raspberry Pi.

 

A wide range of power sources, from plug packs to batteries or solar panels and more may be used with Blade.

 

We'll cover this in a separate post.

Assembling BitScope Blade

In principle, using Blade is as simple is plugging in one or more Raspberry Pi and optionally HAT, CAP or HUB cards, inserting a programmed SD card and connecting the power. However, there are few preparation steps first.

Step #1 Install Nylon Spacers

After unpacking your BitScope Blade, the first thing to do is install the nylon spacers.

 

Installing Nylon Spacers to BitScope Blade Reloaded.

 

These are required to mount the Raspberry Pi in each BAY and a HAT (if using Blade Uno). Repeat for each corner in each Raspberry Pi and the HAT BAY.

 

Step #2 Install Adhesive Stand-Offs (Optional)

 

The stand-offs make it easy to sit the Blade on a flat surface. Install them like this.

 

Installing Stand-Offs to BitScope Blade Reloaded.

 

There are four stand-offs supplied, one for each corner of the Blade. The stand-offs have adhesive feet so you can peel off the labels and stick the Blade to your desktop or use them to mount the Blade on a wall. Once they have been stuck onto a surface they cannot be removed (without destroying the adhesive) so choose where you want the Blade carefully before removing the labels. However, the Blade can be removed from the stand-offs by carefully squeezing the post.

 

Step #3 Check Power Shunt

 

The red power shunt should be pre-installed but if not, connect it as shown here.

 

BitScope Blade Raspberry Pi Power Shunt.

 

The power shunt allows the Raspberry Pi to be powered on and off without disconnecting power to the Blade itself. Normally it's connected and left as is. In a Blade rack or other type of multi-Blade installation and with Blade Duo and Quattro, it allows each Raspberry Pi to be individually powered down (e.g. to replace an SD card).

 

Step #4 The Raspberry Pi

 

If you're using Raspberry Pi 3 and plan to mount the Blade in an enclosure or a confined space with limited ventilation, we recommend you apply a heatsink like this.

BitScope Blade Raspberry Pi 3 Heatsink.

If the Blade is mounted vertically (e.g. on a wall) or in a ventilated Blade Rack a heatsink may not be necessary but if you're planning on doing some compute intensive work, we'd still recommend it. If you're using using Raspberry Pi 2 or Model B+ or A+ a heatsink is unlikely to be necessary. Heatsinks are sold separately.

 

Step #5 Camera & Display

 

The Raspberry Pi Camera and a touchscreen Display is supported, one for each Raspberry Pi on the Blade.

BitScope Blade Raspberry Pi Camera Installation.

BitScope Blade mounts each Raspberry Pi "upside down" and there is a slot in the Blade to pass through the camera cable. If you plan to use a camera, you will need to thread this cable through the slot before connecting to the Raspberry Pi. Once the cable is plugged into the camera connector, the Raspberry Pi is mounted on the Blade (see below).

 

If you want to use a Raspberry Pi Display as well, the connection is similar but located at the edge of the Blade. In this case you can connect it after the Raspberry Pi is mounted on the Blade. It's also possible to physically mount one Raspberry Pi Display on the Blade board itself. We'll devote a new post explaining how to do this. If you want to use an HDMI display, you can connect this to the Raspberry Pi in BAY 1.

 

Likewise you can connect an audio cable to the Raspberry in BAY 1 as well. In both cases, this can be done after the Blade is fully assembled.

 

Step #6 Install Raspberry Pi

 

Plug in a Raspberry Pi in each Pi BAY you plan to use on the Blade.

 

BitScope Blade Raspberry Pi Installation.

 

A reminder, if you're using a camera, you will need to connect the ribbon cable to the camera connector on the Raspberry Pi before installing the Raspberry on the Blade. And yes, the Raspberry Pi is meant to be installed "upside down" on the Blade! Ensure the Raspberry Pi is seated firmly before moving on.

 

Step #7 Install HUB Card (Optional)

 

If you're using one or more HUB Cards, connect them underneath each BAY as shown.

 

BitScope Blade HUB Card Installation.

 

It's probably best to install the card in BAY 1 before you connect the stand-offs. However, if the stand-offs are already installed they can be removed temporarily quite easily.

 

Step #8 Install HAT (Optional, Blade Uno Only)

 

If you're using Blade Uno, you can install almost any Raspberry Pi compatible HAT.

 

BitScope Blade Uno Raspberry Pi HAT Installation.

 

All the J8 connector signals from the Raspberry Pi are made available to the HAT BAY so regardless of whether the HAT uses GPIO, I2C, SPI or serial I/O, they will work with Blade. BitScope Blade also accepts BitScope "extended HATs" (which we call "CAPs"). These devices have the same form factor as Raspberry Pi and can be mounted on any Blade including Duo and Blade Quattro.

 

Step #9 Tighten Screws and Install SD Card

 

The last step before applying power is to tighten all the screws and install the SD cards.

 

BitScope Blade Tighten Screws and Install SD Card.

 

It's not strictly necessary to install the screws if you're planning to remove and reconnect the Raspberry Pi and/or HAT frequently as the friction of the connectors will hold both in place on a desktop. However, if you're using this in an installation we highly recommend all screws be used to ensure nothing comes loose.

 

When the SD card is plugged in, you're ready to connect power and use your Blade. Don't remove an SD card from a Raspberry Pi when power is applied to the Blade unless you have disconnected the BAY power from by removing the shunt. On Blade Duo and Quattro, it's also possible to signal or interrupt the Pi via this header.

 

Step #10 Connect Power via 2.1mm socket

 

Normally power is applied to the Blade via the 2.1mm power socket.

 

BitScope Blade Connect Power via 2.1mm Socket.

 

Any power source terminated with a 2.1mm (centre-positive) plug and rated between 9V and 48V of 20W or more (10W minimum for Blade Uno and Duo) may be used.

 

IMPORTANT: the original Blade boards used a 2.5mm socket. The new ones use 2.1mm. There are a number of reasons for this change which we'll explain an a forthcoming post. Adapters to convert between them are available.

 

Step #11 Connect Power via the tabs

 

There is an alternative way to power any Blade, via the mounting tabs.

BitScope Blade Connect Power via the mounting tabs.

Alligator leads are shown here to make polarity clear but normally this method of power is used in Blade Packs and Blade Racks to minimise power wiring like this:

BitScope Blade Cluster Pack Example - It's Alive!

It's not necessary to use the tabs, indeed they can be shorted together and power applied via the 2.1mm power sockets on each Blade (because Blades include a blocking diode). At this point you're ready to go. There are quite a few things we've mentioned but not yet explained such as BitScope CAPs, BitScope Blade Cluster Packs and Racks, power supply options, software choices and more. We'll publish full details in new posts soon.

 

Post reprinted with permission from the BitScope Blog.

Following our post about the Blade weather station in Nepal, this one describes an interactive exhibit created with BitScope Blade UnoBitScope Blade Uno, BitScope CAP and a Raspberry Pi 3Raspberry Pi 3. The BitScope Blade was used to conveniently power and mount the Raspberry Pi and BitScope to create a stand-alone oscilloscope and spectrum analyzer as part of the museum exhibit.

 

The MAAS PowerHouse Museum sought to create an interactive exhibit to demonstrate how a Theremin works. They originally thought they'd bundle up a bulky and expensive oscilloscope and associated electronics to display the Theremin output but after meeting us the Sydney Maker Faire they decided to try something smaller and easier to mount which operated without user intervention.

 

They ultimately built this impressive exhibit.

GF10A-theremin-exhibit.jpg

Why did they do this?

The Powerhouse Museum offers visitors a wide range of interactive exhibits.

Advocates of learning by doing and having fun while you do it, they sought to create an entertaining exhibit where visitors could play the theremin hear the results.

However, it was not enough just to be able to hear the instrument play, they wanted to be able to visualise the sounds it produced to help explain how the instrument works.

They sought a cost effective solution that could be built into the exhibit itself. It needed to be reliable, start without operator intervention and continue to work 24x7 when powered on.

Built with BitScope, Blade Uno and Raspberry Pi

MAAS used BitScope Blade UnoBitScope Blade Uno together with a Raspberry Pi, BitScope and LCD monitor to build the exibit.

GF10A-theremin-museum-exhibit-bill-of-materials.jpg

Together with the off-the-shelf accessories shown here they had everything needed to build the installation.

The Raspberry Pi, powered and mounted on the BitScope Blade Uno, provided the compute platform to drive the display (via HDMI) and it ran the BitScope application.

The BitScope itself, also mounted on the Blade, was connected (via USB) to the Raspberry Pi and powered by the Blade.

The Theremin output was connected via splitters (so they could also be connected to a sound amplifier) and BNC terminated coaxial cables to the analog inputs via a BitScope probe adapter.

The entire assembly was mounted on the exhibit via the Blade's M3 mounting tabs, and the power, HDMI and audio cables routed through the back and is powered by a single 12V adapter.

BitScope Pi on Display

The team at MAAS decided this assembly should be part of the exhibit itself, so they housed it in a transparent case.

GF10A-theremin-exhibit-electronics-mounted.jpg

Mounted on the exhibit next to the display and above the Theremin it resulted in a visually appealing exhibit for visitors to interact with, hear the sounds produced and watch the waveforms as they played.

We enjoyed working with the MAAS team to put this together and we're impressed with the museum exhibit they built.

BitScope Pi Industrial

This exhibit proved to be a great example of what a Raspberry Pi, BitScope and a BitScope Blade Uno can do but it's not limited to just exhibit installations.

With the launch of the new BitScope Blade range with our friends at element14 last week, we'll publish more examples like this explaining how BitScope, Blade and Raspberry Pi can be deployed.

For example, shown here is a Blade Uno with a Raspberry Pi, a PiFace Digital 2PiFace Digital 2 and a pair of BitScopes (underneath).

GF10A-industrial-blade-example.jpg

An assembly like this offers the ability to capture, analyse and display four high speed analog channels and 16 digital via the BitScopes while also controlling up to ten digital outputs (two via relays).

All sorts of industrial modules like this can be built with Raspberry Pi, BitScope and the full range of Raspberry Pi HATs from third parties using BitScope Blade Uno.

If you have specific application requests or examples of your own, contact us!

About the Theremin

An test instrument like BitScope MicroBitScope Micro is the perfect tool to display and analyze what the Theremin can do and we're big fans of all sorts of electronic musical instruments, so we thought we'd post some information about the Theremin itself.

Leon Theremin plays his instrument.

The Theremin is the world's first electronic musical instrument.

Invented in 1920 by Lev Termen, also known as Leon Theremin, it was a by-product of research into proximity sensors in Russia around that time.

It's played without touching it.

The Theremin consists of a box-like body with two antennas: one is a straight vertical rod which controls the pitch (usually on the right for right-handed players), the other is a horizontal loop (usually on the left) shaped somewhat like a cane handle which controls the volume. The pitch and volume of the note are controlled by the distance of the hands from the antennas.

The block diagram below outlines the basic circuit.

The Theremin employs heterodyning, an electronic technique that mixes two oscillators operating at different frequencies to produce a new lower frequency equal to the difference between them.

In the case of the Theremin, it's the pitch you hear.

GF10A-theremin-block-diagram-CC-BY-SA-3.0.jpg

The pitch oscillator operates at a very high (RF) frequency making it very senstive to any changes in the capacitance in resonsant circuit from which it's built. Moving your hand around the pitch antenna changes the capacitance which changes the frequency of this oscillator and therefore the heterodyne pitch that is produced.The volume control also works via proximity of the performer's hand to the other antenna.

In this case it changes the "efficiency" of the a separate RF oscillator. The closer your hand is to the antenna the lower the amplitude of the oscillator. This amplitude is turned into a volume signal using an envelope detector (a diode rectifier) and applied to the output changing the volume heard at the output.

In the case of the MAAS exhibit, the Theremin output is displayed as a waveform and (optionally) as a spectrum. As visitors play the Theremin they can see the waveform pitch (visible as a changing number of waveform cycles on the display) and the volume (visible as the vertical size of the waveform).

While they did not do this, it would be possible to use the BitScope to display the operation of the pitch and volume oscillators inside the Theremin and analyse how its electronic circuits work but we'll leave that for another day!

Post reprinted with permission from the BitScope Blog.

We launched the new BitScope Blade product range exclusively with element14 last week. To help explain how BitScope Blade works and what you can use it for, we'll be publishing a series of posts, of which this is the first, describing some example applications that can benefit from using Blade to power and mount Raspberry Pi, sometimes in quite challenging circumstances.

 

In this case, a team lead by Prabesh Sapkota and Binod Kandel from the Robotics Association of Nepal↗ built a battery backed solar powered weather station at very low cost using BitScope Blade UnoBitScope Blade Uno, Raspberry Pi and Arduino. The result of a series of STEM workshops created and lead by Australian educator Michelle Jensen↗ in 2016 and run with the help of Nepalese enthusiasts, this amazing project showed how BitScope Blade can be used to power electronics and computers in remote areas without access to reliable power.

 

Why did they do this?

GF10B-prabesh-sapkota-bitscope-blade-uno-nepal.jpg

Weather forecasting in Nepal is difficult because there is no national weather service and the high mountains produce highly variable conditions within just a few kilometres. A reliable and inexpensive weather station is therefore a vital tool for farmers and those living in remote villages. The weather station design had to be very low cost, reliable, easy to maintain, operate on solar power and use readily available motorcycle batteries for when the sun does not shine.

 

Raspberry Pi, BitScope Blade and Arduino

Clearly Raspberry Pi and Arduino are ideal as the basis for building a system like this. The problem for both platforms is how to get a reliable source of uninterrupted 5V power to run them.

GF10B-raspberry-pi-bitscope-arduino-nepal.jpg

BitScope Blade Uno offered the perfect solution, powering the Raspberry Pi directly and the Arduino via one of its auxiliary power ports. Shown here are the core components put together initially as a prototype with a breadboard just to prove it all worked when powered from a 12V source. It did, so Prabesh and Binod pulled together all other materials required:

  1. Arduino UNO
  2. Raspberry Pi 3
  3. Raspberry Pi 7" Touch Screen Display
  4. GPS Module (NEO-6M-0-001)
  5. Pressure sensor (BMP180)
  6. Humidity sensor (DHT11)
  7. 12V Lead Acid Battery
  8. 20 Watt Solar Panel
  9. Hall Effect Sensor (anemometer)
  10. Reed Switch (8 pcs) (wind direction)
  11. PVC pipes, wood, bearings
  12. PCB (Printed Circuit Board)

The Weather Station has sensors for temperature, barometric pressure, humidity, wind direction and speed as well GPS coordinates. All the sensors are connected to the Arduino to record data which is then sent to the Raspberry Pi for capture and display on a dashboard. Prabesh and his team wrote the weather station software and created the display dashboard all running in Raspbian Jessie for the Raspberry Pi.

 

Building the Prototype

GF10B-binod-kandel-bitscope-blade-uno-nepal.jpg

Binod built the prototype assembling all the electronics using the breadboard before the PCB was ready.

 

Key to the project was BitScope Blade Uno because without it, it would not have been possible to power the system. When deployed, power is provided by a 12V lead acid motorcycle battery. A 20 Watt solar panel charges the battery and can also provide direct power.

 

As the sunlight varies during the day and as the battery charges and discharges, the supply voltage in a simple system like this can vary considerably. The system works well because BitScope Blade has an efficient built-in voltage regulator to manage the variable supply accepting any input voltage from 9V to 48V and producing a reliable 5V at up to 4A output for the Raspberry Pi, Arduino and all the sensor electronics. As Prabesh said, "The Weather Station would not be possible without the Blade. It made the whole project for us."

 

Weather Station One

With all the components assembled and testing the first weather station was installed.

GF10B-weather-station-one-bitscope-blade.jpg

The assembly was mounted on the roof.

The electronics was housed in a simple waterproof plastic container and the 12V battery positioned beside it under the adjoining roof.

The solar panel was mounted beside the electronics and the anemometer for wind speed and the wind vane for wind direction mounted on wooden panels next to it.

It was a fascinating and highly educational experience for the people involved.

Having proven reliable in operation since September 2016, the team are now planning to run a series of regional workshops on basic electronics with the assistance of their Australian sponsors and install more weather stations in rural schools and remote areas. Arduino made connecting and using the sensors easy. Raspberry Pi was at the heart of the monitoring and display system and BitScope Blade Uno provided the platform required to mount the Raspberry Pi and power the Pi, Arduino and all sensors. All that was required was a 20W solar panel and a standard 12V lead acid motorcycle battery (as the uninterruptible power supply battery) to run the station 24x7.

Raspberry Pi is increasingly popular in developing countries but reliable power is often not available. Blade offers a low cost solution enabling the use of Raspberry Pi and other electronics when grid or other power sources are unreliable.

Post reprinted with permission from the BitScope Blog↗.