I am trying to make multiple 8x8 bi color LED matrix to work with Intel Edison. I am using I2C ports present on the Edison Arduino kit and it seem to be I2C 6 bus being enabled. I run into problem when i connect multiple LED backpacks (Each with unique address, as i am using Bi color LED backpack with 3 bit addressing i.e. 8 addresses from 0x70 to 0x77), i was able to make only 5 to work at the same time, the moment i attach the 6th one, the display hangs on all of them even if i try to re upload the code but it doesn't work unless i remove the 6th LED backpack. At first i speculated that it might be a power problem, and may be there isn't enough drive current to make more than 5 LED to light up but this doesn't seem to be the case and it is I2C bus that is crashing because i can see I2C register dumping in Putty's Linux Terminal using serial port of Edison. The moment i attach the 6th backpack the I2C crashes.    I was able to make some progress by playing around with pull ups and pull down resistors, adding external resistors and also changing internal port resistance of Edison which gives me option for 2k, 20k, 50k and 910 ohms. 

By default it is set top 50k. I added external 2k pull downs (surprisingly pull ups didn't work) on SDA and SCL lines going to LED backpacks and set the internal port resistance of Edison to 2k. With that configuration i was able to light up 8-10 LED backpacks (few with repetitive addresses as there are only 8 unique addresses) however, the problem still persists when i try to add more and I2C crashes again. And i am not able to lower the value of the external pull down any lower i.e. 1k because then nothing works at all.  I would really appreciate if someone can point out what is going on the background and how to upscale properly and fix these crashes.    Re: Intel Edison I2C Crashing With Multiple Adafruit Bi Color LED Backpack This message was posted by Intel Corporation on behalf of Hello ahsan211, This in fact could be a power issue as the output current of the I2C output is limited and if this limit is surpassed, it could make the bus crash. So, the first thing I would try to use an external power supply to power the I2C devices.

I believe the reason why the pull-down resistors seemed to improve the bus' behavior is because you were decreasing the charge exposed to Edison's output. timberland backpack 23lHowever, when you started to add additional LED backpacks you increased the charge again and you might have reached the current limit again. marmot kosmo backpack reviewTry using an external power supply for the LED backpacks and let me know if the issues persists, I'd be glad to help if that was the case. gewa backpack straps cello Thanks Peter for your elaborate response i appreciate that. owl backpack asda

Yes, i am powering my I2C devices from an external power source which can provide enough current to all I2C devices simultaneously, and current limitation doesn't seem to be the problem as devices are not showing any sign of dimming as well. stihl br550 backpack blower parts list I understand, in that case, it would be interesting to see the I2C signal the Edison is outputting. mavrik backpackDo you have access to an oscilloscope or to a logic analyzer? Comparing both the output before the I2C bus crashes to what happens when it crashes. Have you tried verifying these signals?-Peter. Hi ahsan211,Do you have any updates on this? Can you check the signals with an oscilloscope or a logic analyzer?-Peter.Adafruit 1.2" 8x8 LED-Matrix mit I2C-Backpack, rot19 % USt zzgl. Sofort versandfähig, ausreichende Stückzahl

Adafruit 1.2" 8x8 LED-Matrix mit I2C-Backpack, rot Der Adafruit LED-Matrix Bausatz beinhaltet ein vollständig getestetes und aufgebautes I2C-Backpack, eine 8x8 LED-Matrix in rot und passende Stiftleisten. Die 64 LEDs werden über den LED Treiber HT16K33 angesteuert, welcher wiederum mit nur zwei Pins über I2C angesteuert wird. Adafruit bietet hierfür entsprechende Bibliotheken. Die I2C-Adresse des Backpacks kann mithilfe von drei Jumperverbindungen geändert werden, wodurch die Ansteuerung von bis zu acht I2C-Backpacks an einer I2C-Schnittstelle ermöglicht wird. Zum Aufbau des Bausatzen werden Lötkenntnisse benötigt. Weitere Informationen und Tutorials finden sich auf Adafruit!There is a lot of great kit available for the Raspberry Pi to experiment and learn from, and they don’t have to cost a lot of money.  Here are 3 great examples! This little I2C module neatly connects to the Raspberry Pi with 4 pins (3V3, Gnd, I2C Data and Clock), and potentially can be connected in multiples.

For a bit of fun it is excellent, particularly for creative kids (or 8bit junkies from BBC/Z80 Spectrum days) to design tiny cute icons. Keep an eye out for my follow up to this, as I’ve been experimenting with it with great results. The kit comes in three parts, the pin header (I’ve used my own to add a socket on top), the PCB and the 8×8 module, which are easy to solder together. For I2C, the following pins are used. 3V3 (VCC) – P1 Pin1 Gnd (GND) – P1 Pin6 I2C Data (SDA) – P1 Pin3 I2C Clock (SCL) – P1 Pin5 The Adafruit tutorial contains links and details of the python libraries used for controlling the backpack.  With several useful commands to set individual pixels, or Rows in various colours. Note: The Bi-Colour module allows for 3 different colours, using Red and Green combined to make Yellow. I came across Adafruit’s guide on using the PWM pin of the Raspberry Pi to control a servo and saw it was relatively easy to do.  

So I ordered a ultra-cheap Servo (from Hong-Kong) and waited a few weeks for it to arrive (I had other projects to play with, so I didn’t mind waiting). When the servo arrived and I immediately hooked it up.  You’ll note that the guides below recommend using a separate power supply for the Servo, and I do too (I have used it directly from the RPi 5V supply, but you can expect a reset if you connect it while it is running, and don’t be surprised if it causes lock-ups and resets when it needs to move, depending on your power supply). I’ll spare you all the fine details of how to wire it up and the software side, since the two guides below cover it extremely well indeed. /products/815) which was featured in Issue 6 of the MagPi in the PiGauge article (see article on Issuu). 1. Connect the Gnd (usually black or brown) of the servo to your GND/negative terminal of the power supply (4xAA batteries or similar) and also to the GND pin of the Raspberry Pi (Pin 6 of P1)

2. Connect the +V (usually red wire) of the servo to your power supply positive terminal. 3. Connect the Servo signal wire (usually white, yellow or orange) of the servo to GPIO#18 (Pin12 of P1) 1. Use a spare SD-card (or backup your current one) and install Occientalis 0.2. Note:  You can install the kernel on your current set-up, but I didn’t find it easy to undo, and Occientalis 0.2 lacks a lot of the tweaks from the recent Raspbian images which makes the Raspberry stable and faster (so I would recommend only using it for experimenting with).  No doubt, the Raspbian build will be updated to include the PWM support later on (or even software PWMs) and Occientalis may get updated. 2. See the guides for example Python code, which writes to the PWM pin and controls the position of the Servo. Note: You may wish to remove anything connected to the analogue audio, since there is a certain amount of interference generated. As you can see, I placed my servo into my Little R2D2 (my desk tidy for spare resistors and wires) with the help of some tape.  

He can sit on my desk shaking his head at me all day long. Introducing the PCF8591P – catchy name isn’t it! ~£4 (GBP) for Chip from RS/Farnell Now this little chip is rather useful since not only does it provide us with some well needed analogue inputs (4 channel 8-Bit ADC (Analogue-to-Digital-Converter) – provides input values 0 to 255), but also throws in an analogue output too (8-Bit DAC (Digital-to-Analogue-Converter)). I was looking into this chip in order to create a new kit, so I was testing it out using one of my breadboards. However, following some investigations I came across this useful blog by John Newbigin: He does an excellent job at providing some simple commands to quickly test out the operation of the chip (what I was looking for), but he also points you in the direction of another of my favourite sites, Deal Extreme.  I’ve often brought kit from Deal Extreme so it was great to see they stock the following item: Not only does the module include the surface mount version of the chip I was testing with, but it also includes a light sensor, temperature sensor and a variable resistor (so you have inputs right there to test with immediately or they can even be used in your project).  

I shall confirm when I get mine, if they are connected to the jumpers to select between them and the input pins (I expect this is the case). All for $4.50 delivered – Hence why there isn’t much point me attempting to create a kit! The good news is that this module can easily add analogue inputs and outputs to your Raspberry Pi and being I2C based, it is easy to control and multiple modules can be put on the same I2C bus. Again, for I2C the following pins are used. Since my first test was using the bare chip, it wasn’t too pretty but it worked! As I was simply testing out the chip, I only made use of the i2cget() and i2cset() commands to make up a quick script to poll and read the channels. For my testing I connected up a variable resistor to act as a potential divider, and later on some IR proximity sensors and they all seemed to work nicely. I manually tested the analogue output using similar commands separately, using a multimeter to monitor the output (i2cset -y 1 0x48 0x41 0x88) – where 0x88 is the output value 0x00 (LOW) to 0xFF (HIGH).