I had to add a 12V controlled output for my raspberry Pi to connect a radio frequency system to my Pi. This system just need 12V to start transmitting but it needs 12V ! The raspberry can offer 5V or 3.3V. The solution is to use a currant elevator system. The one I built is based on a Texas Instrument component TPS6734, able to deliver 120mA / 12V with a 3.3V input.
Last year in December, I gave a talk on Internet of Things, here is the youtube video (in French) – The slide are also here : http://slid.es/disk91/internetofthings
RfRpi card is a RF433 emitter and receiver add-on of Raspberry Pi. This card is based on high quality receiver and transmitter I have selected after tests you can find here and here. This article describes how to get start with this shield.
To buy this shield the best way is to sent me a comment on this post, the price is 60€
The Shield is now working with Raspberry PI B+ and previous versions. The Shield is also working with Raspberry PI 2+. For these two last version you need to compile a kernel driver.
I had to control power on an external circuit using an Arduino. the objective was to delay the power-on of a device consuming about 3A. One of the solution is to use a relay but it is a quite expensive solution another one is to use a Mosfet. This is the solution I’ll describe here.
For one of my project, I needed to have a >3A power supply to put in my car, delivering stable 5V. For this I tried different power supply from ebay used for phone & tablets. One of them was not so bad if you connect it after engine start. The main issue with these power supply is the poor quality of the filtering and engine start spike cancellation. As my circuit is sensitive to this spike, I decided to build my own power supply.
Here is the summary of this experience … click next !
Since a couple of day at work I had to investigate on some network issues for an application, it seems that we have a strange ARP configuration that may be the main issue… by the way, I discovered another strange thing where icmp packets sent in burst mode (like a flood) are lost at variable rates. Here is the note on my investigations
For one of my projects, I want to have a really low power consumption device to be able to use a battery for many month. For this I implemented a low power solution as described here. I’ll try to simplify it a little bit and document it a little more …
RFduino connected to HC-05 bluetooth
I was looking for a system able to work with an iPhone (Bluetooth Low Emission – LBE) and a standard android (Standard bluetooth / rfcom). The RFDuino Arduino platform I have is perfect for BLE so, I decided to add a HC-05 module for the standard bluetooth.
Here is the description on how to make it !