Chemical compatibility of LEDs application note from OSRAM. Link here (PDF)
The performance and stability of light emitting diodes (LEDs) may be influenced by various chemical incompatibilities arising from chemicals and materials used, amongst other things, in luminaire construction, or by gases in the proximate environment of LEDs during field operation. Nevertheless, LEDs have to fulfill a wide range of customer needs and requirements in indoor and outdoor applications.
This application note provides information about the chemical compatibility of certain substances with LEDs, particularly with regard to some of their basic components. In this context, the main mechanisms of chemical incompatibility are illustrated using examples of blue and white LEDs.
After 2 years and 200 videos. Time for another competition! The prizes I have two prototype Super Duper Logger boards to give away along with one NanoPi Neo and a Nano Pi Neo Air. So a Super Duper board and NanoPi will go to a Patron and another Super Duper and NanoPi will go to regular subscribers. You can check Continue reading The 200th video competition. Woohoo!→
After having published my previous posts about the JQ6500 module, some readers wrote me about an error the MusicDownload.exe application shows when they click on the upload button to store the mp3 files in the flash memory.
The error is
flashdata error, have not define program mode in flashdata.ini!!
It seems that the application is not fully compatible with Windows 8 or 10.
To solve the problem, you only have to enable the Windows 7 compatibility mode:
With this setting, the upload process runs fine:
In the following video, you can see all the required steps:
This easy to make box uses no batteries but can still power a lot of stuff. It really is a very versatile little BoostPack based device. It would be the perfect thing to have on hand in times of emergency.
After seeing this giant mechanical keyboard at Adafruit, I decided I had to build my own. Adafruit made theirs out of wood and used one of their Python-compatible microcontroller boards. I wanted a sloped top on my keyboard. I also wanted to check out what was new with Microchip’s USB device stack. I decided to build my keyboard out of aluminum and use a PIC18 microcontroller.
In a previous post I presented the JQ6500 audio module. When you connect it to your computer, it’s detected as a CDROM drive.
I brought some modules from different webstores. A couple of them gave me the following error when I tried to browse the content of the CD:
Unable to access the disk. The disk may be damaged.
It seems that some manufacturers do not program the flash memory of the chip and therefore it doesn’t contain the MusicDownload.exe application.
Luckily, thanks to the work by Reinhard Max and Nikolai Radke, it’s now possible to recover those modules. From Nikolai’s Github repository it’s possible to download an ISO image with a minimal Linux distribution and the recovery toolkit:
After having downloaded the image, you can burn it to a CD (or use software like UNetbootin to transfer it to a bootable USB drive) and restart your PC with that image.
However, there is an alternative way: the use of VMware Workstation Player, a free virtualization software (for non-commercial use) by VMware. Using this application it’s possible to start a virtual machine on your PC that can run the recovery ISO image.
At the end of this post you can find a video that shows all the following steps…
Let’s see how to do it. After having installed the application, create a new virtual machine:
Choose I will install the OS later:
Select Linux as operating system:
Give the VM a name and select the folder where it will be saved:
You don’t really need an hard disk, so you can specify a small size for it (for example 1Gb):
Now you have to configure VMware Player to start the VM using the ISO image. Click on Customize Hardware:
Select the CD/DVD drive and connect it to the ISO image downloaded from Github:
Before starting the VM, verify that your module is not connected to the computer:
Wait for the boot process to complete. The toolkit (started automatically) will warn you that it wasn’t able to identify any modules:
Open the Removable Devices menu and note down all the listed devices:
Now connect the module to the USB port. If you open the menu again, you should be able to identify which device corresponds to your module:
Connect it to the virtual machine:
Perform a new scan typing the l command. If everything is ok, now the toolkit should be able to identify the module:
Depending on the size of the flash memory of your module, choose the correct menu item. Most modules are sold with a 16Mbit or 2Mbyte memory chip:
At the end of the recovery process, you can shut down the VM and verify that your computer is now able to display the disk content:
Nui is an IR controlled volume controller for analog audio. It sits between your audio source and speakers and can amplify or reduce the volume using IR commands (and eventually BLE).
Why do I need this?
It all started because I have my trusty Logitech Z-2300 speakers and subwoofer I purchased back around 2004/5. They still work great, but instead of being on my computer, they are used for my TV. Unfortunately, the TV’s line out doesn’t honor the TV’s volume and is always outputting at max volume. Sure, I can get up and change the volume on the speakers themselves, but wouldn’t it be more convenient to do it with the TV remote?!
That’s how the Nui project started. It sits between my TV and my speakers and now I don’t have to get up to change the volume :D
I like perfboard, especially the ones with plated trough holes. But I also like SMD components, and more and more fun IC’s are not available in DIP. So a while ago I designed some perfboard with 1.27mm pitch, making some SMD parts like SOIC stuff easy to prototype on it, and also mix THT and SMD stuff.
Looking for a nice little project to build on it, I came across a frequency counter made with 7400 logic, perhaps not the most efficient approach, but a fun one at that. I made a few changed to the design, partly because of some components I already had like the 74HC160 and 4543 (yes, not 7400 but still logic :P) and partly to improve on the design, for example by adding a 10Mhz oscillator instead of a NE555 as the clock source. The current end result looks like this, a case is ordered and a follow up post will be made when the project is nicely tucked away in a case.
For some time, on different chinese webstores (for example Banggood) there is a module called JQ6500 for sale:
it’s often described as a voice sound module or as an MP3 player sound module.
Actually JQ6500 is the name of the main chip hosted on the module:
The chip is manufactured by a Chinese company named JQ. A datasheetfor the chip is also available, unfortunately only in Chinese (but Google Translate can help to understand what it contains).
On the other side of the PCB, the module houses two additional integrated circuits:
a 16Mbit flash memory (25L1606E)
a 3W audio amplifier (HXJ 8002)
When you connect the module to your computer via USB, it is detected as a CDROM drive. If you browse the content of the CD, you can find the MusicDownload.exe application that allows to upload audio files in the flash memory:
The software is in Chinese but its use is very simple: by moving to the second tab you can select the MP3 files to be uploaded. If you now move back to the initial tab, you can start the upload process clicking on the only available button. In the video at the end of this post you can see how it works…
You can control the JQ6500 chip in different ways. The easiest one is using external buttons connected to pins K1-2-3-4-5:
When you press a button, the chip plays the corresponding audio file. For example if you press the button connected to pin K1, the chip plays the audio file named 001.mp3.
The onboard amplifier (HXJ 8002) is a mono IC and its output is connected to pin SPK+ and SPK-. You can therefore connect to those pins a small speaker. If you want a stereo audio, you can instead use pins ADL_L (left channel) and ADC_R (right channel) and connect them to an external amplifier.
This module is an excellent and inexpensive solution to add audio to your projects. The use of an internal flash memory has the advantage of not requiring SD cards or other media to store your audio files; in contrast its capacity (16Mbit = 2MByte) makes it more suitable to reproduce sound effects / guide voices than to make a music player.
In the next articles I will show you how to interface the module with Arduino … meanwhile here is a video showing my first tests: