Tag Archives: DIY

E-ink Display Driven DIY

via hardware – Hackaday

E-ink displays are awesome. Humans spent centuries reading non-backlit devices, and frankly it’s a lot easier on the eyes. But have you looked into driving one of these critters yourself? It’s a nightmare. So chapeau! to [Julien] for his FPGA-based implementation that not only uses our favorite open-source FPGA toolchain, and serves as an open reference implementation for anyone else who’s interested.

Getting just black and white on an E-ink display is relatively easy — just hit the ink pixels with the same signal over and over until they give up. Greyscale is made by applying much more nuanced voltages because the pixels are somewhat state-dependent. If the desired endpoint is a 50% grey, for instance, you’d hit it with a different pulse train if the pixel were now white versus if it were now black. (Ever notice that your e-book screen periodically does a white-black flash? It’s resetting all the pixels to a known state.) And that’s not even taking into account the hassles with the various crazy voltages that E-ink displays require, which [Julien] wisely handed off to a dedicated chip.

In the end, the device has to make 20-50 passes through the screen for one user-visible refresh. [Julien] found that the usual microcontrollers just weren’t capable of the speed that he wanted, hence the FPGA and custom waveform tables. We’ve seen E-ink hacks before, and [Julien] is standing on the shoulders of giants, most notably those of [Petteri Aimonen] and [Sprite_tm]. [Julien]’s hack has the fastest updates we’ve ever seen.

We still can’t wait for the day that there is a general-purpose E-ink driver chip out there for pennies, because nearly every project we make with a backlit display would look better, and chew through the batteries slower, with E-ink. In the meantime, [Julien]’s FPGA implementation is pretty close, and it’s fully open.


Filed under: FPGA, hardware

DIY thermal vision shoots 360 panoramas

via Dangerous Prototypes

pics-result_fixed_big-600

Saulius Lukse has posted his DIY 360 panoramas:

It might seem simple task but it involves some tricks to control motors and read sensor data from two separate controllers.
One of the challenges I faced is meshing position and temperature data. Feedback received from each controllers is timestamped. After scan is complete timings are being analyzed and each temperature value is assigned interpolated coordinate from motor feedback. If done incorrectly (brute forced) this procedure can take hours. Luckily there are tricks to speed this up to few seconds. Hint: Python numpy searchsorted.
Another annoying (but luckily easy to fix) task is correctly and evenly visualizing data. Unless you oversample few times there will be black dots on complete picture. In photography they are called dead pixels. In our situation it is pretty easy to spot these pixels and filling is done by averaging neighboring ones.

Project info at Kurokesu blog.

MPPT solar charger rev c

via Dangerous Prototypes

pics-20170331_SolarCharger_008-8-600

Lukas Fässler from Soldernerd has been working on revised version of his MPPT Solar charger project:

Over the last few weeks I have been quite busy with my MPPT Solar Charger project. I’ve built up a first board and started writing firmware for it. Since the last version was not too different in terms of hardware I was able to re-use most of that code. But I hadn’t even touched on the whole USB stuff back then so there was still a lot of work to do. While the project is still far from being complete I am happy to say that I’ve made quite some progress. Most importantly, the new design seems to work well and so far I haven’t found any mistakes in the board layout. But let’s go through this step by step.

More details at Soldernerd homepage.

MPPT solar charger rev c

via Dangerous Prototypes

pics-20170331_SolarCharger_008-8-600

Lukas Fässler from Soldernerd has been working on revised version of his MPPT Solar charger project:

Over the last few weeks I have been quite busy with my MPPT Solar Charger project. I’ve built up a first board and started writing firmware for it. Since the last version was not too different in terms of hardware I was able to re-use most of that code. But I hadn’t even touched on the whole USB stuff back then so there was still a lot of work to do. While the project is still far from being complete I am happy to say that I’ve made quite some progress. Most importantly, the new design seems to work well and so far I haven’t found any mistakes in the board layout. But let’s go through this step by step.

More details at Soldernerd homepage.

Homebrew PiHPSDR

via Dangerous Prototypes

pihpsdr_rp

g4fre built his own PIHPSDR, that is available at github:

Having seen the Apache-labs version of the PIHPSDR I wanted to customise it to fill my needs, so I needed to build my own
All the needed information , with the software, is at John Melton’s github site github.com/g0orx/pihpsdr The hardware shopping list includes. RaspberryPi 3, 7″ Official Raspberry Pi LCD, 8 push buttons, 4 rotary encoders, case and power supply.
All the items were mounted in a 12x7x2″ aluminium case obtained from Mouser, The display was held in place with plastic channel finishing strips from B&Q.

More details at g4fre radio blog.

5V Regulator Cap for 9V battery

via Dangerous Prototypes

Test-leads-supplied-power-by-loops-or-interconnect-wires

David Cook built a 5V regulator to sit atop a 9V battery:

For quick portable projects and temporary hacks, it is often faster to reuse a simple 5V regulator circuit than to integrate a power supply into the device design. My toolbox has an LED tester and magnifier light, so why not add a convenient 5V regulator cap to the collection? There are nicer ones on the market that have surface mount components, but half the fun of an electronics hobby is creating something basic in your own style. This double-decker board with flashing LED power indicator allowed me to experiment with flush battery snaps and board interconnects.

More details at David Cook’s Robot Room project page.