Tag Archives: Raspberry Pi

CORATAM with the Raspberry Pi

The ubiquitous Single Board Computer, the Raspberry Pi, or the RBPi is a perfectly suitable candidate for CORATAM or Control of Aquatic Drones for Maritime Tasks. Sitting within each drone, an RBPi becomes a part of a swarm of robotic systems. Portugal is using this novel method for exploring and exploiting its maritime opportunities as the sea is one of the country’s main resources. Although land-based and air-based swarms of robots have been extensively used for studying the aquatic environment for the proposed expansion of Portugal’s continental shelf, swarms in aquatic environments are a different breed altogether.

Tasks in aquatic environment are usually expensive to conduct. This is because of all the special operational requirements of manned vehicles and support crews. Therefore, Portugal has thought of an alternative approach where they have used collectives of relatively simple and inexpensive aquatic robot swarms. As each robot is easily replaceable, these have a high potential of applicability for essential tasks such as prospecting sites for sea border patrolling, bridges inspection, sea life localization, environmental monitoring, aquaculture, and so on.

The collectives of robots work on a decentralized control based on the principles of self-organization. This gives them the capability of performing efficiently on tasks that require robustness to faults, scalability, and distributed sensing.

With the development of CORATAM, Portugal is hoping to achieve three main objectives. The first is to explore the novel approach of control synthesis in a set of maritime tasks, but in the real world. The second is to develop a swarm of aquatic robots with fault-tolerant ad-hoc network architecture, heterogeneous in nature and scalable. The third is to disclose all the hardware and software components developed under an open-source license, to enable others to build their own aquatic robots.

Each robot is about 60 cm in length, and inexpensive, as the designers have used all widely available, off-the-shelf hardware. Each robot uses a differential drive mono-hull boat, which can travel at a maximum speed of 1.7 m/s, in a straight line. The maximum angular speed the robots can achieve is 90°/s.

An RBPi-2 SBC supports the on-board control of each robot. They communicate via a wireless protocol (802.11g Wi-Fi) and each broadcasts its UDP datagram. The neighboring robots and the monitoring station receive the broadcast, forming a distributed network without any central coordination or a single point of failure. All robots are equipped with compass sensors and GPS, and each broadcasts its position to the neighboring robots every second.

All robots use prototype hardware, making it inexpensive when compared to the majority of the commercially available unmanned surface vehicles. Therefore, the robots serve as a platform suitable for research and development, and easily maintainable. Additionally, the open source nature of the platforms makes them suitable for different manufacturing processes, sensory payloads, design choices, and different actuators to be used.

An artificial neural network-based controller controls each robot. The normalized readings of the sensors form the inputs of the neural network, while the output of the network controls the actuators on the robots. Each sensor reading and actuation value is updated every 100 ms.

Oracle, Raspberry Pi and a Weather Station for Kids

Kids now have a wonderful opportunity of learning about their world while at the same time enhancing their programming skills. The Raspberry Pi Foundation is teaming up with Oracle to create an initiative – The Oracle Academy Raspberry Pi Weather Station. The initiative is inviting schools to teach their kids programming skills by applying for a weather station hardware kit that children can build and develop.

With the firm’s philanthropic arm, Oracle Giving, funding the first thousand kits, schools can get the kits without incurring any expenditure – until the stocks last. Students have the freedom to decide how to build their application. They will be using elements that SQL developed in collaboration with Oracle, while the data collected will be hosted on clouds belonging to Oracle.

The scheme is targeted at children between the ages of 11 and 16. Apart from honing their crafting skills for building the weather station, schoolchildren will also learn to write code for tracking wind speed, direction, humidity, pressure and temperature. In addition, students are also encouraged to build a website for displaying their local weather conditions. Children participating in the scheme can connect with other participants via a specially built website that doubles up to provide technical support.

According to Jane Richardson, director at the Oracle Academy EMEA, the scheme can lead to gratifying and effective careers for children as they learn computer science skills, database management and application programming. The goal of the project is twofold. Primarily, it shows children that computer science can help them in measuring, interrogating and understanding the world in a better way. Secondly, the project provides them with a hands-on opportunity to develop these skills.

The weather station is built with the Raspberry Pi or RBPi SBC as its control station. The complete set of sensor measurements the weather station handles includes Air quality, relative humidity, barometric pressure, soil temperature, ambient temperature, wind direction, wind gust speed, wind speed and rainfall. All this is measured and logged in real time with a real-time clock. Although this combination helps to keep the cost of the kit under control, users are free to augment the features further on their own.

Kids go through the scheme via three main phases of learning – collection, display and interpretation of weather parameters. In the collection phase, children learn about interfacing different sensors, understanding their methods of working and then writing code in Python for interacting with them. At the end of this phase, kids record their measurements in a MySQL database hosted on the RBPi. For this, students can deploy their weather station in an outdoor location on the grounds of their school.

In the display phase, kids learn to create an Apache, PHP 5 and JavaScript website for displaying the measurements they have collected from their weather station. They can upload their measurements to the Oracle cloud database, so that could be used by other schools as well.

In the interpretation of weather phase, children learn to discern patterns in weather data, analyze them and use that to predict future weather. For this, they can use both the local data they have collected and national weather from the online Oracle cloud database.

CHIP Competes With the Raspberry Pi

The extremely popular tiny, credit card sized, inexpensive, single board computer, the Raspberry Pi or the RBPi may soon have a rival. So far, the contender, known as the CHIP, is waiting for its crowdfunding project to complete. In the future, expect more of such similar devices jostling the market place.

Unlike the RBPi, CHIP is completely open source – for both its software and its hardware. Once in the market, the design and documentation will be available to people to download. Therefore, with the schematic available, people will be free to make their own version and add improvements or tweaks to the design.

CHIP’s operating system is based on Debian Gnu Linux, which means it will support several thousand apps right out of the box. On the hardware side, there are some improvements on the specifications of the RBPi. As against the 700MHz CPU of the RBPi, CHIP runs on a single core CPU at 1GHz. Users can do without the SD Card, as CHIP has storage memory of 4GB built into the card. The 512MB RAM is the same as that in the later models of the RBPi. While users have to add separate dongles for Wi-Fi and Bluetooth when using the RBPi, CHIP has both built on-board.

CHIP can connect to almost any type of screen. Its base unit offers composite video output, but there are adapters for both VGA and HDMI. An optional case for the CHIP enables it work with a touchscreen and a keyboard. The entire package is the size of an original Game Boy.

All this may not be surprising since there have been prior competitors with better specifications and more features than those of the original RBPi do. However, all the competitors so far were unable to beat the price factor – they were all more expensive than the RBPi. This is the first challenger bringing the price lower than that of an RBPi – the basic unit of the CHIP costs only $9. The Next Thing Co., the manufacturers, call this the “world’s first nine dollar computer,” and in their opinion, CHIP is “built for work, play and everything in between.”

Along with a lower price tag, CHIP has a smaller profile than the RBPi. As it has a more powerful processor and more memory, CHIP could easily replace RBPi as the primary choice for projects. The entire board is packed with several sockets and pins. Its hardware features include a UART, USB, SPI, TWI (I2C), MIPI-CSI, Eight digital GPIOs, parallel LCD output, one PWM pin, composite video out, mono audio in, stereo audio out and a touch panel input.

Users of CHIP will learn coding basics and play games on the tiny computer that may soon usurp the title of king of the budget microcomputers, so far being enjoyed by the RBPi. CHIP measures only 1.5×2.3 inches and is compatible with peripherals such as televisions and keyboards. It runs on Linux, works with any type of screen and comes with a host of pre-installed applications. Therefore, users can simply make it work out of the box, without having to download anything.

Raspberry Pi and a Simple Robot

Using a pair of DC motors and connecting them to two wheels can be the basics of a simple robot. Once you add a single board computer to this basis structure, you can do almost whatever your like with your robot. However, making a robot do more than simply run around requires many mechanical appendages that may prove difficult to get unless you have access to a workshop or you are proficient with 3D printing.

To simplify things for beginners, the robot chassis from Adafruit is a versatile kit. With this simple robot kit and a single board computer such as the Raspberry Pi or RBPi, you can start your first lessons in robotics.

As the kit is for beginners just starting with their first robot, there are no sensors. A Motor HAT (Hardware Attached on Top) controls two motors connected to two wheels on a chassis. The front of the chassis has a swivel castor, which makes it stable. The RBPi mounts on the chassis and a battery supplies the necessary power for the SBC and the motors.

Once you are familiar with generating a set of instructions in Python to make the robot move the way you want it to, you can start adding sensors to the kit. For example, simply adding a camera will allow the robot to see where it is going. Adding an ultrasonic range finder will allow the robot to avoid bumping into obstacles in its path.

The Mini Rover Robot Chassis Kit from Adafruit includes almost everything one needs to build a functional robot. It has an anodized aluminum chassis, two mini DC motors, two motor wheels, a front castor wheel, and a top plate with standoffs for mounting the electronics.

It is convenient to use the latest RBPi models such as the Model 2, B+, or A+, as these have suitable mounting holes that allow easy attachment to the robot chassis. Although it is also possible to use the RBPi Zero, its small size makes it unsuitable to mount the motor HAT securely.

The Motor HAT can drive DC and stepper motors from the RBPi and is suitable for small robot projects. The brass standoffs help to hold the Motor HAT securely to the RBPi. Power comes from two sources. One 4x AA battery pack supplies the motors. Another small USB battery pack powers the RBPi. The RBPi also requires a Wi-Fi dongle to keep it connected to the computer and to control the RBPi robot.

Your RBPi must be running the latest version of the Operating System – Raspbian Jessie. If you do not have this, allow the RBPi to access the Internet and download the necessary software.

The Motor HAT library examples included provide adequate software for this project to start. For example, you can use the example scripts provided to make the robot move forward, backward or to turn in different directions. Preferably, place the robot on level ground, where there are no obstacles. As the robot has no sensors, it can hit something or easily fall off the edge of a table.

Remote Controlled Car with a Raspberry Pi

A single board computer such as the Raspberry Pi or RBPi can work wonders on a remote controlled car. Running Python on the RBPi allows it to handle three tasks a remote controlled car needs most – self-driving on a track, detection of sign and traffic lights and avoiding front collisions. The RC car has three subsystems – input units consisting of a camera and ultrasonic sensors, a processing unit and a control unit.

The processing unit on the RC car communicates with the RBPi to handle several tasks. These include receiving data from the RBPi, training, and predicting the neural network, detecting objects, measuring distances, and sending instructions to the Arduino through the USB connection.

The computer also runs a multithread TCP server program for receiving streamed image frames and ultrasonic data from the RBPi. The computer converts the image frames into gray scale and decodes them into numpy arrays.

To make object recognition and steering simple and fast, the RC car uses a neural network. The advantage is once the network is trained, it can work with only the trained parameters, making predictions very fast. The output layer of the network has four nodes corresponding to the steering control instructions – forward, reverse, left, and right. The input layer has over 38,000 nodes and uses only the lower half of the input images for training and prediction.

Although the project uses the shape-based approach for object detection, it only focuses on detecting the stop sign and traffic lights. Detection and training was both using OpenCV using both positive and negative samples. Positive samples are images that contain the desired object while negative samples are random images without the desired object.

The controller on the RC car needs four low-going signals corresponding to the forward, reverse, left, and right actions. Four pins on the Arduino provide these signals simulating button-press actions that drive the RC car.

The ultrasonic sensor measures the distance of an obstacle in front of the RC car. This includes measuring proper sensing angle and other surface conditions. Other measurements from the Pi camera allow the RC car to stop at the correct distance from the object.

The monocular vision approach of the RC car makes it difficult to get accurate distance measurements. In turn, other factors also influence the distance measurement, which includes errors in the actual measurement, variations in detecting the bounding box of the object, and nonlinear relationship between distance and camera coordinates. The error increases when camera distances are great and the camera coordinates are changing rapidly.

The traffic light recognition process uses image processing for detecting red and green lights. First part of the training involves detecting the traffic light by decoding its bounding box. Next, Gaussian blur reduces the image noise to find the brightest point within the bounding box. Finally, red or green state determination within the brightest spot detects the actual state of the traffic light.

The project uses an RBPi Model B+, a Pi camera and an ultrasonic sensor, HC-SR04. The RBPi streams ultrasonic sensor and color video data via its local Wi-Fi connection. It scales the video down to QVGA resolution to achieve low latency.

A Microscope with the Raspberry Pi

If you require a microscope, you can make one as a proof-of-concept using the RBPi or Raspberry Pi. It is simpler if you have a bagful of LEGO parts to build the structure, but you can also go with Plexiglas construction. Apart from being a useful addition to a science laboratory, making a microscope with the RBPi is a good way of learning computer programming and making things with your hands.

The microscope uses an electronic camera for resolving images and its maximum resolution is about 5µm per pixel. That means you will be able to see and analyze dust, salt, hair and fruit flies – objects mainly in the range of a 20th of a millimeter to 5mm. Since at high resolutions only a small area will be in focus, you may confront distortion and color effects, commonly known as chromatic aberration. That precludes seeing cell culture or blood cells.

If you make the microscope construction from pre-produced parts and do not glue them together, it will allow for subsequent modifications, optimizations and adaptations for special applications, if necessary. You will need an RBPi2 with its SD card, a keyboard, mouse, a monitor or TV. You will also need an electronic camera similar to the WaveShare B, along with a 50 cm cable. For the pre-produced parts, you can refer here. The illumination comes from a 1.6W LED lamp working off a 9V block battery, operated through a small switch.

The construction of the microscope starts with a base plate and a sled tray for placing and holding objects or object glasses. Then there is a tower for holding the plate, which acts as the camera mount. You should be able to move the camera plate and the object sled orthogonal to each other for placing the camera precisely above the object.

There are two ways to focus the camera. You can adjust the length of the columns of the camera tower to get a coarse adjustment – this will adjust the distance between the object and the camera lens. For a better focus, you can then turn the camera objective manually. You may have a worm gear arrangement with a toothed rack (possibly from the LEGO collection) and you can use that to adjust the focus. The gear wheel with toothed rack could guide the object tray and the worm gear could be attached to the camera.

For processing images from the camera, there is a large choice of software to use. You can use very good GUIs available for raspivid (video capture) and raspistill (for still images). Alternatively, you can use raspistill along with Mathematica and its image analysis functions, for processing the images for subsequent analysis.

You can also use PiVision, which offers an option to preview the image to see if the camera is properly focused on the area of interest, before capturing the image as a still photo. During preview, PiVision allows changing the options setting for expanding the preview image to get more details and to re-focus, if necessary. Once you have captured the image, remove the unwanted areas by cropping it.

The Raspberry Pi Goes to Zero

If you thought the legendary Raspberry Pi or RBPi was the smallest single board computers could get, well, you need to think again. Not only has the famous SBC shrunk in size, it has become a lot cheaper as well. The charitable Raspberry Pi foundation that launched the best selling computer in the UK is now offering their next model, the RBPI-Zero and in the US, it costs just $5.

RBPi-Zero comes with a 512MB RAM and a core that boasts of being 40-percent faster than what the RBPI-1 came with. The miniaturized SBC sports a Mini-HDMI port and two Micro USB ports, one of them for power. While comparing the RBPI-Zero with the first RBPI, the Raspberry Pi Foundation says the RBPI-Zero is equally revolutionary. They explained it would be manufactured in Wales, run the full Raspbian, while including other applications such as Minecraft and Scratch.

Similar to the requirements for the RBPi, the RBPi-Zero requires the user to attach their own power supply, keyboard, mouse or any other input device and the display screen. The cost of the new board is low because several components from the RBPi board are no longer present or have been simplified for the RBPi-Zero. According to Uben Upton, the founder of Raspberry Pi, all components on the new board justify their existence.

However, cutting features was not the sole process of getting the RBPI-Zero down to the bare-bones pricing of $5. The major contribution comes from the grand success of its predecessor, the RBPi, being the most successful computer in the UK for decades. The massive sales have enabled the Foundation to cut costs to unimaginable levels. The sheer numbers in sales have given them the economies of scale.

One of the processes in reducing the cost of the RBPi-Zero was keeping all components on one side of the board instead of two – it simplified manufacturing by removing half the assembly costs. According to Upton, they have moved the physical product around and the cost of metal connections has made an impact.

By redesigning the RBPi-Zero, the engineering solution to the necessities of space and cost has resulted in an extraordinarily aesthetic board. The precision and beauty of Zero comes out in its compactness and its symmetry. Just like its predecessor, nothing is hidden and all its inner workings are exposed to anyone with an interest. As Upton says, it is nice when things look attractive because they are functional.

The small form factor of the RBPi-Zero makes it simple for the board to be used in many more projects, whether it is robotics or Internet-connected devices. The easy to use board massively increases creative possibilities. You can use the RBPI-Zero in places where the RBPi would be difficult to fit. Presently, the Zero, a full-featured computer, will provide raw power somewhere between the first generation of the RBPi and its second generation.

The launch plans for the Zero are massive, with tens of thousands ready to ship. Raspberry Pi magazines such as the Magpi will feature a freebie RBPi-Zero with its 10,000 issues. Upton is expecting five such launch partners.

3D Printer based on the Raspberry Pi

3D printers are becoming so very popular now and you can get them in many different sizes and configurations to suit your purpose. AON, a company providing 3D printer services in Montreal has built a prototype of a high-end dual extrusion 3D printer. A notable feature about this printer is the huge build volume of 129,600 cubic centimeters, which users can heat up to 70°C. However, most importantly, the device has an SBC that runs it – a Raspberry Pi or RBPi running the open source Linux Operating System and a 3D printer host software named OctoPrint.

AON was frustrated with the limitations of dual-extrusion printers available. They had to contend with limited build volumes, high failure rates and warped and cracked products. AON decided to address the above problems by building their own 3D printer. The result was an RBPi based high-end, 3D printer with a huge build area – 18x18x12 inches or 45x45x64 cm.

Estimated at an eventual retail price of US$4,000, the AON 3D printer (still a Kickstarter project) may not exactly be an impulse buy, since consumer 3D printers are available from $300 onwards. However, the discount price for this fascinating printer finds favor in a write-up in the 3Ders.org website.

The AON 3D printer makes use of FDM, or Fused Deposition Modeling. This is a thermoplastic extrusion technology and most other 3D printer manufacturers such as the MakerBot Replicators use it. However, the difference is AON offers dual extruder heads that operate independently.

Users printing a complex object can speed up the printing by using both extruders simultaneously. Alternatively, printing of two identical designs is possible using the same or different colors or filament materials. To prevent waste of plastic oozing from a temporarily inactive extruder, the user can park the extruder off to one side.

To heat the chamber up to 70°C, the AON 3D printer uses its 1800W heaters. AON claims this helps to reduce cracking and warping with use of high-end materials such as Polycarbonate, Nylon or ABS. The printer allows printing with PLA or other special high-temperature materials and eliminates heat creep with special devices. These include high-end E3D Volcano hot ends reinforced with a heat-resistant thermocouple and cooled with water. Another robust feature is the high-end XY gantry that can travel at 500mm/s on the XY axis.

The printer, with a size of 80x90x125cm, integrates an Azteeg X3 Pro controller board. This features SD8825 SureStepr motor drivers and the Wi-Fi enabled RBPi. According to AON, the price includes the preloaded OctaPrint and a license for a copy of the Simplify3D printer software.

As the RBPi is Wi-Fi enabled, users do not need to tether a laptop. They can use any web browser to link to OctaPrint, which runs on the RBPi or any other embedded Linux board, supporting a huge variety of 3D printers. All usual print control features are available with the web interface, and this includes uploading and previewing the gcode files. Users can also configure custom controls. Remote visual monitoring via a webcam is possible, including remote temperature monitoring.

An SSD Shield for the Raspberry Pi

CSB502SSD is a multifunction storage shield for the Raspberry Pi or RBPi 2, model B. A Rhode Island based startup, Pi2Design has designed the shield and makers of the embedded modules, Cogent Computer Systems have manufactured it. The designers have targeted the shield for a variety of industrial, medical, data storage and embedded applications.

Earlier, Pi2Design had offered the PiDrive SSD expansion card to users with a 128GB mSATA solid-state drive. The CSB502SSD plugs in directly into one of the USB ports of the RBPi and similar to the PiDrive, the CSB502SSD sips power from the RBPi. Therefore, it does not completely deplete the RBPi of power, leaving enough for other peripherals.

For both products, users do not need to buy a powered USB hub for plugging in the standalone SSD – that makes them more portable. The PiDrive is a simple storage-only device and powered via its USB connection to the RBPi. More fully featured and equipped with an onboard DC/DC converter, the CSB502SSD accepts inputs from 8 to 25VDC. The shield comes with a 2A, 12VDC wall-plugin power brick. Although the price does not include the SSD, the CSB502SSD supports up to 1TB models. You also get a microUSB-B to USB-A patch cable, a Wi-Fi antenna and mounting posts with the kit. For an extra amount, you can upgrade the power brick to one of 5A rating.

The CSB502SSD has many features. Its supply powers both itself and the RBPi, including additional features such as a temperature sensor, a real time clock or RTC, a Wi-Fi radio and much more. There is also a four-port USB hub, of which two hubs are free to use – one port is for connecting to SATA and the other for connecting to the Wi-Fi. Communication between the RBPi and the CSB502SSD is via GPIO and the I2C interfaces.

Among the specifications for the CSB502SSD is a single-wire Dallas/Maxim DS18B20 temperature sensor. With this, you can monitor the health of the SSD using the I2C interface and a unique ID of 64-bits for managing assets. The DS1339 RTC from Dallas/Maxim has a programmable alarm powered by a coin cell battery backup – this ensures proper time keeping even when the network access is lacking. The 802.11b/g/n Wi-Fi module from Ogemray, the GWF-3M08, has a Soft-AP Mode support, providing 150Mbps and an on-module IPEX connector for antenna placement.

The mSATA socket can handle up to 1TB SSD storage and because of the Prolific PL2571 SATA II bridge controller, offers great Linux support for USB to SATA. The two USB 2.0 ports can provide up to 1.5A power per port and the 40-pin mating connector can let you plug the shield directly on the RBPi 2.

Onboard the CSB502SSD is a 5V, 10A supply to power all peripherals in addition to the RBPi, which can take up to 2.5A. With the multi-function CSB502SSD shield, users can create a low cost, high-performance networked storage device for embedded systems. With the powerful combination of the RBPi 2 and the CSB502SSD, users can take advantage of the ever-expanding RBPi 2 ecosystem and applications.

The Raspberry Pi Zero Has It Simplified

The release of the new Raspberry Pi Zero or RBPi-Zero has taken the technical world by a storm. This tiny SBC has a 1GHz ARM11 System on Chip, 40 GPIO pins, micro-USB ports, a mini-HDMI port, a micro SD card slot and works with 512MB RAM. The 65×30 mm card has gone on sale with a price tag of a mere $5.00.

The Broadcom BCM2836, clocked to 1GHz, runs Raspbian Linux. Not only is the RBPi-Zero 40 percent faster than the original RBPi Model B, it is also 40 smaller than the B+ model of the RBPi. Although almost identical in size to the RBPi Compute Module, the RBPi-Zero has the real-world ports that the former lacks. However, like the A+ Model, the Zero lacks the Ethernet port.

People looking for the Broadcom chip on the RBPi-Zero will be disappointed at not finding it on either the top or the bottom side of the board. The Raspberry Pi Foundation has adopted the Package-on-Package or PoP manufacturing technology for RBPi-Zero. Therefore, although the Broadcom chip is present on board, the Elpida 512MB RAM chip sits piggyback on top of the Broadcom chip, hiding it from view.

The RBPi-Zero lacks the USB ports, DSI and CSI ports and the audio jack. That is because it is intended for IoT- and embedded-focused hackers. The manufacturers have kept the same 40-pin expansion header other modern RBPi boards possess. Therefore, users can attach available HATs or other expansion boards and adapters. Moreover, the Zero can run any application meant to run on the Model B+.

To use the RBPi-Zero, users will need additional cables. Although most users will have these lying around, others may need to buy them and some more. The best way to start is to go with the Adafruit kit, which is selling two versions in the US market – the Budget Pack and the more expensive Starter Kit. Other vendors offer different combos for accessories.

The Budget Pack of Adafruit comes with a RBPi-Zero board along with a 5V, 1A power supply, USB-A to USB-micro B cable, an 8GB Class 10 SD Card for the OS, a Micro-USB to USB OTG cable, 2×20 Male header strips and a Mini-HDMI to HDMI adapter.

The Starter Kit from Adafruit includes the above and adds more 2×20 male and female headers, USB Console cable and a Wi-Fi dongle. With the USB Console cable, you can put up an alternative display in place of the HDMI.

The Essential Kit from PiHut offers all the items of the Budget Pack of Adafruit (except the SD Card) and includes four rubber feet, one single row of 20-pin GPIO header, one dual row of 40-pin GPIO header, one dual row 40-pin female GPIO header and one dual row 40-pin right-angled GPIO header.

Pimroni offers similar kits to the two above, but offers useful zero-sized PiHATs. These include the Explorer pHAT, the Scroll pHAT and the pHAT DAC. The Explorer HAT is suitable for building a tiny robot as it can drive a motor over an H-bridge, has buffered digital IOs and four analog inputs for low-cost sensors. With the Scroll HAT, you can drive 11×5 LED matrix and the pHAT DAC adds a digital to analog converter to your RBPi-Zero.