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RS485 Bricklet

Today we released the new RS485 Bricklet. It is now available in our shop!

The Bricklet supports low-level RS485 as well as Modbus RTU master/slave with full- and half-duplex. The Modbus RTU implementation is fully compliant for reading and writing of coils and registers. Baudrate, parity, stop bits and word length are configurable and a 120 ohm termination can optinally be switched on with a DIP switch.

It is one of the new co-processor Bricklets with a connector for the 7p-10p Bricklet cable. The Bricklet uses some of the many new possibilites that co-processor Bricklets can offer. It has a 10kb send- und receive buffer (the buffer size of the old Bricklets was limited to 256 bytes at most). The Modbus RTU implementation is comprehensive, with the old system it would have only be possible to implement this with a Brick. Additionally the RS485 Bricklet uses the new Streaming-API (see below).

Streaming-API

Together with the new Bricklet we will release new featuers for our APIs. Until now an API function (e.g. getTemperature) did always generate exactly one packet, which was exchanged between your PC and a Brick/Bricklet. A TFP (Tinkerforge protocol) packet can have a maximum payload length of 64 bytes, so a function could always only transfer 64 byte at a time. Because of this, it was only possible to transfer big amounts of data piece-by-piece with many function calls.

With the new Streaming-API it is now possible for functions to transfer an arbitrary amount of data. A rs485.write() call can transfer 1000 byte (or more) at once. Internnaly the calls to the Streaming-API are again translated into 64-byte blocks that are send to the Bricks/Bricklets. The Streaming-API is, like the old API, generated for all of our supported langauges from a config file. We majorly misjudged the amount of time it takes to extend the generators by this new feature. Originally we planned to release the new Streaming-API and the RS485 Bricklet together with the GPS Bricklet 2.0 (over 2 month ago).

The new streaming functions are currently supported in all languages but Delphi, Shell and JavaScript. The three missing languages will be released in the next weeks. We had lots requests regarding the RS485 Bricklets and since we announced a much earlier release date, we decided to do this "partial release". If you need to use one of the three not-yet-supported languages, you can either be patient and wait for the release or use the low-level API that is the basis for the Streaming-API.

The GPS Bricklet 2.0 - a renewed version of the old GPS Bricklet - is now available!

It supports GPS as well as GLONASS. Support for Galileo can be added later on with a software update. It is now also possible to receive elevation, azimuth and SNR for each GPS/GLONASS satellite. It still has the battery for position data backup and all of the other features that the old GPS Bricklet had.

The GPS Bricklet 2.0 is the first Bricklet with a co-processor. This means you need one of the new 7 pole to 10 pole Bricklet cables to connect it to a Brick! Otherwise it will behave exactly like the old Bricklets and you won't notice a difference. Make sure to update the Brick firmwares, support for the new Bricklets is only available in the newly released versions.

We will write more about the new Bricklets with co-processor soon. They will also come with a more powerful API that that not only supports getters, setters and callbacks but also convenient data streaming. This will increase the usability for Bricklets with a high throughput of data significantly. The GPS Bricklet 2.0 does not yet have the new API, but we didn't want to wait any longer to release it! We made sure that we can add it later on.

The old GPS Bricklet had an internal antenna, which was convenient, but it had a small antenna gain. For the successor we decided to use a module without internal antenna and to permanently attach a proper 25x25mm patch antenna to the bottom of the Bricklet. 

Since the antenna is connected through a U.FL connector, you can still connect your own external antenna (for example one with a long cable). If you use our U.FL to SMA adapter, you can also use a standard SMA GPS antenna. The GPS Bricklet 2.0 case features a hole to mount it:

The GPS Bricklet 2.0 is available in our shop for 44.99€. Compared to the old Bricklet we unfortunately had to increase the price by 5€. The price difference comes mainly from the antenna.

After a long development phase we can finally release the new Silent Stepper Brick.

So far only the Stepper Brick was able to controller stepper motors. With the Silent Stepper Brick we offer an alternative to control these motors. Compared to the Stepper Brick, it has a mode to drive stepper motors completely noiseless and it can use a step-resolution as small as 1/256-step.

The Silent Stepper Brick has 3 modes.

• Stealth Mode: Completely noiseless
• Coolstep Mode: Energy optimized
• Classic Mode: Maximized torque

In Stealth Mode the stepper motor is driven nearly noiseless with as little vibrations as possible. The mode is usable for low to medium velocities. In Coolstep Mode the power consumption is automatically reduced during low load times. This ensures that as little heat as necessary is generated. If the maximum torque of a stepper motor is needed, you can switch to classic mode. Classic Mode is very similar to the way the Stepper Brick controls stepper motors.

For these three modes velocity thresholds can be defined. When one of these threshold is reached the Brick changes from one mode into another. Typically this is used to be noiseless in standstill or for low velocities (stealth mode) and to have the maximum torque for high velocity applications (classic mode).

Another feature is Stallguard. It can be used to measure current motor load and for stall detection. In Coolstep Mode this is used automatically to adjust the motor current to the load.

With a small step size like 1/256-step you can drive a stepper motor extremely smooth and precise. If you want to reach high speeds, like 10000 full-steps per second, a step-size of 1/256 would result in a velocity of 2,560,000 steps per second. It is not possible to precisely trigger steps with a frequency that high. We limit the steps to a maximum of 65535 steps per second. However, you can enable step-interpolation. With step-interpolation enabled, you can drive a motor with 10000 full-steps per second and the driver will internally drive every step with 1/256 sub steps, which is the equivalent to the full 2,560,000 1/256-steps.

The Silent Stepper Brick is now available in our shop for 59.99€ including VAT.

We also made a small noise comparison video:

tl;dr: Since mid March we are shipping the Mounting Kits with new plastic washers. They allow for an easier an sturdier mounting of stacks.

In the past it wasn't possible to mount a stack with tightly screwed spacers. The distance between Bricks is approximately 12.3-12.4mm, while the spacers have a length of 12mm. It would have been possible for us to order spaces with the exact length, but during testing we found out that the distance between Bricks can vary slightly (+-0.1mm). We think this is the case since that the board-to-board connector are never soldered on completely the same way. During soldering they may "float on the tin" with slightly different heights.

To remedy this problem, we got custom plastic washers made for us. They have the exact height that is needed for the average distance and they can be easily squished together by 0.05mm during the mounting. This way we can compensate for the tolerances (this was not possible with the metal washers). Additionally the new washers are non-conductive. 

We advice to put the new washers at the top side of the Bricks during mounting, see below.

Currently you can see the Tinkerforge building blocks at Didacta in Stuttgart at the booth of the Rink GmbH. They make trollies that are used by schools and universities to store class sets of notebooks or tablets. At the trade fair they are showing the new "IT experience box". This trolley has different hardware compenents and tools for projects in the IT area. The new trollies contain Raspberry Pis, mini displays and Tinkerforge building blocks. The content of the trolley can be used to do different experiments. Each experiment has a labled plastic plate with the necessary components, instructions and example source code. The trolly also comes with all of the necessary power supplies.

The booth is in Hall 4.F14 and can still be visited until Saturday.