jQuery Plugin that formats JSON strings

in how-to by DP | 1 comment



Matthew Heironimus writes:

This jQuery plugin is based on a nice little JavaScript routine written by Vladimir Bodurov that can be viewed at www.bodurov.com/JsonFormatter.
To use this plugin include jsonFormatter.min.css and jsonFormatter.min.js in your html file. See the jsonFormatterExample.html file for an example on how to do this. If you wish to use the darkTheme, include the jsonFormatter-darkTheme.min.css file.

Available on github.

Posted in how-to | Tagged , , | 1 Comment

PCB Checklist – What to check before you submit

in how-to, PCBs by DP | 0 comments


Baldengineer’s checklist for submitting a PCB to a fab house:

Recently I’ve been expanding my retro game collection to include game cartridges imported from Japan. The problem is that I don’t have Japanese game systems (yet). So I’m creating an open source adapter to convert Famicom carts to the NES. Before I submit the PCB to OSH Park, I’m going to run through this PCB Checklist to make sure I don’t forget something silly.

Posted in how-to, PCBs | Tagged , | Leave a comment

Free PCBs massive fail, now shipping

in Free PCBs, PCBs by Ian | 6 comments


Late last year I spun off the Dirty____ source code into a free PCB fulfillment system (Filthy Hole). The system is modeled after Amazon.com – print packing lists and prepaid shipping/address/customs form on 10x15cm labels. It is way easier for the back office to pick and pack, and follows the same workflow as Dirty PCBs.

Some time around October the system got stuck though and very few packing lists were delivered to the shippers. Today I fixed the bug and we shipped more than 100 free PCB orders.

I’m really sorry for the bug, and disappointed that I didn’t catch and fix it before now. Free PCBs will now ship weekly, and we’ll have a ton new boards available when the dev site launches shortly.

Posted in Free PCBs, PCBs | Tagged | 6 Comments

TwinTeeth: The PCB mini-factory

in hacks, open source by DP | 2 comments


Diyouware TwinTeeth, an open-source PCB mini-factory :

It includes the following functions:

  • UV Laser photoengraving on sensitive film or presensitized boards using an ultraviolet laser.
  • Drilling vias and holes using any mini-rotary tool like Dremel® or Proxxon®
  • Dispensing solder paste with precision on SMD PCB pads
  • Plotting circuits with a permanent pen-maker (if you prefer this method)
  • 3D printing knobs, casings, front-panels, even print circuits with conductive filament, or make circuits supports
  • Milling/Carving soft materials or etching PCB copper with a v-bit (if you prefer this etching method)
  • And much more… because it is extendable and you can use any other tool you can fix on it

Via Hacked Gadgets.

Check out the video after the break. Continue reading →

Posted in hacks, open source | Tagged , , | 2 Comments

3D BRD viewer, a free tool to visualize CadSoft EAGLE PCB designs in 3D

in Eagle, tools by DP | 0 comments


Peter of Cytec BG writes, “My idea was for pcb designers to be able to quickly, whithout too much hassle, check their board for correct footprints (especially for connectors) and collisions between components. Currently one can change soldermask colors, silkscreen layers, move and rotate components around, change component models and import step files.”

For more details visit Cytec.bg website.

Posted in Eagle, tools | Tagged , , | Leave a comment

Piccolo, a tiny CNC bot

in Arduino, open source by DP | 0 comments


Luca Dentella blogged about his Piccolo build:

Piccolo is an opensource project, by Diatom Studio, that consists of a small CNC bot (working area about 5x5cm); the official site is www.piccolo.cc.
I built one unit; the required components are:

  • the frame, laser cut by Vectorealism
  • 3 micro servos, brought from HobbyKing
  • screws, nuts…
  • the PCB (manufactured by SeeedStudio) and one Arduino Pro Micro from SparkFun


Two transistor superheterodyne shortwave receiver

in hacks by DP | 6 comments


Dilshan Jayakody writes:

This is two transistor and two IF transformer based superheterodyne receiver which is designed to receive 13m to 41m bands. With quiet good external antenna this receiver performs similar to commercially available shortwave receiver and its audio quality is in very satisfactory level.
This receiver can be constructing on PCB, breadboard or commonly available veroboard or stripboard. For tuning use Polyvaricon or air variable capacitor. For precision tuning, connect small trimmer capacitor with parallel to variable capacitor’s gangs or use mechanical wheel assembly with the variable capacitor.
This receiver is design to work with 9V regulated power supply and it requires external AF amplifier to drive the headphone or speaker. In our testing we use TDA2050 audio power amplifier with this receiver.

Details on Dilshan Jayakody’s blog page.

Posted in hacks | Tagged , , , | 6 Comments

#FreePCB via Twitter to 2 random RTs

in Free PCBs by DP | 1 comment

KHOS-2-3-4-5-6P Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week:

  • Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Check out how we mail PCBs worldwide video.
  • We’ll contact you via Twitter with a coupon code for the PCB drawer.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

Posted in Free PCBs | Tagged | 1 Comment

WiFi thermostat with weekly scheduler

in hacks, wireless by DP | 0 comments


WiFi thermostat with weekly scheduler project by Martin Harizanov:

As additional feature, I’ve added thermostat function based on Trystan Lea’s Open Thermostat Scheduler, only my code runs entirely off the ESP8266 SoC. The UI is touch-friendly and works great on mobile devices
I’ve also added broadcasting functionality, allowing the board to send its state to third party services like emoncms.org and thingspeak.com. The benefit of this is that the board can now fetch historical readings from the services and render some fancy charts for further business intelligence


Drive a stepper motor with acceleration and deceleration using an Allegro driver on ATmega8

in AVR, hacks, library by DP | 0 comments


Davide Gironi writes:

This library drive a stepper motor using the Allegro A3967 (EasyDriver) on ATmega8. It will also work on the Allegro a4988, and other type of motor driver controlled by the number of pulse received.
It features:

  • direction changing
  • speed changing
  • acceleration and deceleration
  • multiple motor driving
  • stop spinning after number of step, or continuos spinning mode

It would be easly portable on other microprocessor.

Check out the video after the break.

More information on Davide Gironi’s blog page.

Continue reading →

Gophert CPS-3205C calibration

in DIY by DP | 0 comments

Florin of YourITronics writes:

In this video I am calibrating the Gophert CPS-3205C power supply using my Keithley 175 4.5 digit multimeter and my adjustable dummy load.
The calibration procedure is:
1. Set the V/A selector switch to A position,
2. Push the adjust knob then power on the power supply,the meter will display PUSH OFF,
3. Press the ON/OFF button one time then press the LOCK button two times, the unit will go into voltage calibration (please note calibrate the voltage with no load), the voltmeter displays 01.00 and amp meter displays 001.
4. please adjust the adjust knob to set the output voltage to 1.005V,( you can push the adjust knob to select the range of adjusting) then press the ON/OFF button to calibrate the output voltage to 10.00V and 30.00V, after 30V voltage has been calibrated, please press the ON/OFF button to go into current calibration, connect your electronic load to the output terminal of the power supply, the unit must operate in C.C mode,the amp meter displays 1.00 and the voltmeter displays 0001, please adjust the adjust knob to set the output constant current to 1.000A, then press the ON/OFF button to calibrate the output constant current 5.000A,after 5.0A has been calibrated then press the ON/OFF button to finish the calibration.

3.7V Li-Ion battery charger circuit

in power supply by DP | 4 comments


From the comments on our earlier standalone Linear Li-Ion battery charger with thermal regulation in ThinSOT app note post, Jan writes:

Nice chip, indeed. Unfortunately not easy to find stocked – here I can get it only from Farnell (5 euro + VAT a pop) or Digikey ($3/pc + VAT + import duties).
I would rather use something like MCP73831 – costs about 50 cents, same sort of package, but only 500mA max charging current. Which isn’t too big deal in most cases – USB can only deliver 500mA max by default …

More details on ElectroSchematics.

Open source laser cutter

in Arduino, open source by DP | 1 comment


Martin Raynsford has written an article detailing his open source laser cutter project:

Now that I have an easy way to switch controllers into my laser it’s time to try out some of the different softwares. I’m quite comfortable with Arduino and I’ve got a fair few of them kicking round my house so that’s a good place to start so GRBL is the first controller that sprang to mind. It’s a simple G-Code interpreter and there are a myriad of programs that send G-Code out via a serial port.

See part 1 here.

Posted in Arduino, open source | Tagged | 1 Comment

Hacker in residence March, 2015


The slow lazy days of Chinese Spring Festival are behind us. Markets are open and BBQ place is back, but our hacker supply is at the lowest level in recent memory. Jelmer is back in the Netherlands raising money to manufacture his project, and Charles of PAX Instruments is in the US on a posh lecture tour. We need a new BBQ crowd and that could be you!

There’s at least one open desk at our ‘shared storage space’ near Huaqiangbei, the world’s largest electronics market. Make use of our soldering equipment, laser cutter, crap collection, BBQ and bar. If you’re in a position to uproot yourself and hang out in China doing open hardware for the next month please contact me ASAP! You could be our next hacker in residence!

App note: Measure capacitance of Class-II and Class-III ceramic capacitors

in app notes by DP | 0 comments


KEMET’s app note(PDF) on the methods used on measuring capacitance of different classes of ceramic capacitors.

This application note addresses proper capacitance measurement techniques of Class-II (X7R/X5R) and Class-III (Y5V/Z5U) ceramic capacitors and identifies common errors that are made upon incoming inspection or after board assembly. Errors are highlighted and provides instruction for better electrical measurements and results.

Free PCB Sunday: Pick your PCB

in Free PCBs by DP | 69 comments


We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

Continue reading →

Posted in Free PCBs | Tagged | 69 Comments

App note: Bodo’s Power Systems: Capacitors for critical applications get better by design

in app notes by DP | 0 comments


Great read(PDF) from KEMET on the design features and screening methods applied to electrolytic and tantalum capacitors to prevent long-term deterioration or sudden unexpected failures.

Wherever electronic equipment is used such as in the home, at work, in-car, or in defense equipment users typically expect perfect reliability while the technology itself should ideally be invisible or transparent. Numerous aspects of today’s components are evolving to realize this goal, from leading-edge nanometre semiconductor process nodes and chipscale packages to improvements in devices such as capacitors.

App note: Standalone Linear Li-Ion battery charger with thermal regulation in ThinSOT

in app notes by DP | 2 comments


Standalone Linear Li-Ion battery charger with thermal regulation in ThinSOT application note (PDF!) from Linear:

The LTC4054 is a single cell lithium-ion battery charger using a constant-current/constant voltage algorithm. It can deliver up to 800mA of charge current (using a good thermal PCB layout) with a final float voltage accuracy of ±1%. The LTC4054 includes an internal P-channel power MOSFET and thermal regulation circuitry. No blocking diode or external current sense resistor is required; thus, the basic charger circuit requires only two external components. Furthermore, the LTC4054 is capable of operating from a USB power source.

ProtoQube – PQ60 PocketQube Breakout board

in Prototypes by DP | 0 comments


ProtoQube, a PocketQube PQ60 breakout and prototyping board by Ozqube:

The ProtoQube board is a full breakout of the PQ60 PocketQube standard connector, combined with a small .1″(2.54mm) pitch prototyping area. The 20 breakout contacts on each side are .05″ (1.27mm) pitch. The board itself is 42x42mm. This board doesn’t just have to be used for a satellite. The PQ60 form factor is small enough to be used in a variety of projects, such as High Altitude Ballooning (HAB) or Sensor networks. Another benefit of using this breakout board is that you don’t have to use the expensive backplane connector specified in the standard in order to make something the size of a PocketQube. You can stack multiple boards together using 20 pin through hole headers.

More information on Ozqube’s blog page.

Free PCB coupon via Facebook to 2 random commenters

in Free PCBs by DP | 0 comments

buspiratev383 Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters.  The coupon code usually go to Facebook ‘Other’ Messages Folder .  More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

Continue reading →