Day: November 16, 2019

Sow Your Seed Efficiently With This Multi-Way Drop Seeder

November 16, 2019 by 8 Comments

Anyone who has ever had to propagate small plants from seed will know that efficiently sowing seed can be a difficult process. Getting a consistent number of seed in each point while achieving any sort of speed is almost impossible, and as a result it becomes a tedious process. If only there were some means by which it could be automated, perhaps a way to do a whole tray at once!

Fortunately [Michael Ratcliffe] is at hand, with his tray-sized drop seeder. It consists of two sheets of acrylic each with a grid of holes, offset from each other by able to be brought into alignment with a lever. Seed is shaken over the upper surface until all the holes contain some, and then the lever is operated allowing it to drop through into the soil below. There is a matching dibber if required to push the required grid of holes in the soil.

It’s a simple yet ingenious gadget that genuinely will make the lives of horticulturalists a lot easier, even though it might not be perfect for all types of seed. He’s created a video which we’ve placed below the break, and should you wish to create the dibber we’ve already covered it.

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Speeding Up IOTA Proof Of Work Using FPGAs

November 16, 2019 by 5 Comments

Blockchain has existed as a concept since the early 1990s, but keeping a distributed ledger for IoT transactions wasn’t widely implemented until IOTA developed Tangle. The blockchain company was initially founded as a hardware startup and pivoted to work on transactional settlement for IoT. The Tangle, their distributed ledger architecture based on a directed acyclic graph (DAG) works as a “blockchain without the blocks and the chain”.

As its name implies, the Tangle is a web of transactions that references its past two transactions and a subsection of other transactions. Rather than miners and stakers being responsible for overall consensus, all active participants are involved in the approval of transactions. The transaction process requires the client to sign with their private keys, select two random unconfirmed transactions to be referenced, and perform proof-of-work.

The proof-of-work has an unfortunately high difficulty as you might expect. The process is similar to finding a nonce in Bitcoin mining, although the difficulty is set at a lower threshold due to the transactions running on lower-power nodes. Even so, since IOTA transactions commonly occur on small embedded platforms this can take several minutes to complete, a relatively long time considering these are mere transactions.

Since Curl-P81 hashes should be computed in parallel, they can’t be computed efficiently on general purpose CPUs. The PiDiver 1.3, [Thomas Pototschnig]’s port of the IOTA Reference Implementation (IRI) PearlDiver, performs searches for nonces. Because it runs on FPGAs, it is able to speed up the proof-of-work by a factor of more than 140 when compared to a Raspberry Pi. The FPGA is able to calculate one round of the hash in a single clock cycle, and a complete hash in 85 cycles (as well as testing for a valid nonce). Seven parallel hashes can be calculated at once, giving 15.8MHash/s at a frequency of 188MHz. The proof-of-work takes ~300ms on the FPGA when compared to 90s on a Raspberry Pi, so this is a significant improvement in speed.

Since the project is open source, the core can be used by IRI for creating a modified version of their PearlDiver.  The board can be used as a Raspberry Pi HAT, although it can also be connected via USB to work without the Pi.

While this doesn’t address the security concerns of using IOTA with personal IoT devices, it is certainly a significant improvement on the speed of their proof-of-work process, and the software speedup is incredibly satisfying to watch.

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This Is The Bike You Wanted Your Dad To Make You When You Were Eight Years Old!

November 16, 2019 by 22 Comments

The ever-resourceful [Turbo Conquering Mega Eagle] has an excellent excuse for starting on projects, he’s building them for his kids and making videos. We’re not so sure his little motorcycle wasn’t built because Dad also wants to have a go though, because it seems he had quite a lot of fun testing it.

The build starts with a Chinese petrol conversion kit for a bicycle. There’s a little twofour-stroke motor and a basic chain drive to a large sprocket intended to fit on the opposite side of a bicycle wheel to the pedal sprocket. He uses a pair of pneumatic wheelbarrow wheels for which he makes a new bush and to which he welds the sprocket. These go into a fairly simple hardtail frame for which he makes a padded motorcycle seat, and from then on he’s ready to go.

The result is a rather cool little non-road-legal motorcycle that we suspect most readers will have a hankering to own. We’re not so sure about its seeming lack of brakes though. Judge for yourself, the video is below the break.

This isn’t the first home made small bike we’ve brought you, though it’s a lot safer than the first one.

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