CheMaRy Web Page

Electronics, DIY, programming and more…

Category Archives: DIY

Programming Bus Pirate v4 without ChipKit

While on vacations I started a project where I needed to program a device (nRF52833) via SWD, as a programmer I wanted to use a Bus Pirate v4.0 I had on hand and OpenOCD.

After some hours of unsuccessful attempts I arrived to the conclusion that the firmware of my Bus Pirate has some bug on JTAG/SWD function. I downloaded newer firmware from and tried to burn it using pirate-loader but I was unable to communicate with the device even shorting PGC-PGD, tried lots of things until I remembered last time I programmed Bus Pirate was with my own compiled firmware and PICKit instead of using BP own bootloader, so probably I deleted accidentally the bootloader.

My only option was to program the Bus Pirate using directly the ICSP port, but my PICKit is at my home far away.

Read more of this post

Make you own wire wrap tool

2014-12-21_144743_447.avi_snapshot_00.52_[2014.12.31_00.50.41] copy

I was always intrigued about what is wire wrapping, I already have two wire wrap wire reels bought at eBay some time ago for 8 EUR (12 USD) each but I use it as connection wires for soldering.

Thanks to this great explanation of Bil Herd at hackaday I discovered what it is and how useful can it be for prototyping. I immediately went to buy a wire wrap tool online and I found it cost at least 20 USD, to expensive for the usage I will give to it.

Here I will explain how did a simple wire wrapping tool with results like a professional one. Read more of this post

DIY Power over ethernet (PoE)


At my home the ADSL router and my room are in the opposite sides of the house, the Wifi signal that arrives to my room is so low that I can barely use it on my phone or tablet. I have an Ethernet cable that goes from the router to my room so I decided to place a Wifi access point in the middle.

The problem is that there is no power outlet around, the solution is to send the power over the Ethernet cable (PoE) along with the signal. There are commercial products that do it, but is funny doing it yourself and I have an old WRT54GC wifi router that is perfect for that. Read more of this post

Emergency USB charger for mobile


Having to travel often for work and I suffered some times the nuisance of having the mobile battery almost drain and not being able to find an outlet to charge it. Emergency chargers are widely available but I prefered to build my own.

This is the bill of material I used:

  • LED flashlight for AAA or 18650 batteries (0,5€ eBay)
  • Solar Boost DC-DC 3V-5V Adjustable Power Supply Module (3€ eBay)
  • 8650 battery (3.7V 2600mA) and charger (less than 5€ eBay) Read more of this post

Remote shutter for Canon S95 from a wireless doorbell


Are you tired of explaining to your family that they have to remain still until the camera timer triggers? on every family celebration the same history. I always wanted a remote shutter so I don’t have to rely on the camera timer, and if I can construct one for few bucks, much better!

The software CHDK adds to Canon cameras functions that are not present by default, in my case I have a Canon S95 and CHDK lets trigger the shutter when a 5V signal is detected on the USB port. Read more of this post