I have been using the TMP36 for years, with Arduino, BeagleBone and now the Spark Core/Photon. It has often been reported in the Arduino forums that this chip is inaccurate and unreliable. Indeed a quick glance at the datasheet tells you accurate to 2 degrees C (which seems pretty poor).
I'm working on a Spark Core project for a book and tried out a TMP36. The results seemed totally mad, -25C when it should have been 17C. I checked the maths which was all fine. Then, thinking I had
CPC very kindly sent me a Raspberry Pi model B+ to try out.
As you can see, there are a few changes when you compare it to the Raspberry Pi Model B in the middle and the model A on the right. This board is a pretty serious upgrade to the Model B while still being very affordable at just £22.87 + VAT (about $40).
Raspberry Pi, models B+, B and A
The most obvious change is that there are now four USB ports rather than the two of the Model B. This i
The Raspberry Pi uses a pretty modest amount of electricity and it is perfectly possible to run in for short periods using batteries. In this post, I will look at some of the options for making your Pi run on batteries.
How Long Will the Battery Last
Whatever technology you use to battery power your Raspberry Pi, there is one key figure for the battery that you use that will determine how long you will get. This is the battery capacity in mAh (milliamp hours). So, if a
As a teenager, I had one of these calculators and I recently came across a non-functional one advertised on eBay and couldn't resist.
These calculators used a strange battery pack that had two NiCd AA cells, along with a buck-boost chip to raise the voltage to 9V. Of course 30+ years on and in most cases these batteries leak and destroy the buck-boost PCB.
Fortunately its pretty easy to replace the NiCd pack with a PP3 9V battery.
The latest product from MonkMakes is a robot kit that I have designed using the RaspiRobot Board v2 (RRB2). The kit is available from MonkMakes.
The kit comprises:
* a robot chassis, including two gearmotors and a 6 x AA battery holder.
* a RaspiRobot Board v2 (RRB2) that plugs onto the Raspberry Pi and controls the motors, as well as providing power to the Raspberry Pi itself. It uses a switch-mode power supply that can provide the Pi with up to 2A
When IkaLogic (www.ikalogic.com) offered to send me one of their Scana Plus logic analyzers, I was delighted. Not least because the software to support this USB Logic analyzer is available for Mac. So no more having to crank up a virtual machine running XP and wrestle USB drivers into submission!
The device costs €199 (at the time of writing) direct from the Ikalogic store.
An oscilloscope will often have just two channels and require a fair bit of
I decided to see what other kinds of project can be made from the MonkMakes Raspberry Pi Electronics Starter Kit, that I designed.
The kit comes with project cards and a link to download the accompanying Python scripts. And projects already include a light meter and email notifier, so I decided to combine these two projects into one and make something that will send an email whenever the fridge door is opened.
This is particularly timely as the MonkMakes team are trying to loos
Almost a year ago, I posted a blog entry on the Raspberry Leaf. A template to tell you which pins are which on the GPIO header. This was hugely popular and many people downloaded the PDF and printed their own leaves. Since then MonkMakes has been selling large numbers of ready-made and drilled leaves for the Pi.
I have just finished a book on the BeagleBone Black and of course suffered the same problem of working out which pin is which. Even worse on the BBB because it has so many G
Jack Christensen sent me one of his One Million Ohm's kits, so last weekend, my son and I decided to put it together. Well he made it and I got in the way and 'hovered' like a typical dad.
WARNING: When constructing this project, always remember that Ohm's Law dictates that V = IR, so if you can persuade just 100mA to flow through it, there will be 100,000 Volts generated!
Just kidding. The big resistor in the middle, serves no more purpose than being the butt of the joke. It is surr
I have been experimenting with some Bare Conductive Paint that I bought from CPC after seeing it being used in screen printing at Lancaster's Highwire Lab. The paint is made by Bare Conductive in the UK.
The thirst thing I wanted to know was just how conductive is this stuff. So I cut myself a stencil with tracks of 1mm (40 mils) and 3mm (120 mils) and daubed paint onto the paper below.
It leaked a bit. I am really no good at art. However, the final tracks are good
Recently, Jack Christensen, sent me a few goodies, including this really neat and low cost Real Time Clock (RTC) module. A RTC is useful, because it will keep track of the time even when the power is removed from your Arduino. It uses a long life lithium battery.
It comes assembled apart from the header pins which are included and just need soldering. You only really need to solder header pins to the I2C side of the board. Its a nice design, the pin headers holes just the right size
One of the most frequently asked questions of me is 'where can I buy the parts for X' where X is one of the project in my books.
In an attempt to remedy this situation, my partner Linda and I have started on little on-line store (monkmakes.com) to make and sell things related to by books. That will include the books themselves, signed by the author if you wish (this is very good for my ego) but also kits of parts.
The web store is based in the UK, but we have no problems with shippin
The Raspberry Pi does not have any analog inputs, but that does not mean that you can't use some types of analog sensors. Using a couple of resistors and a capacitor, you can use a "step response" method to measure resistance. Which is just great if you are using a pot, photoresistor or thermistor.
The Recipe that follows is taken from my new book "The Raspberry Pi Cookbook". This way of using sensors was inspired by this work from Adafruit.
To make this recipe, y
The Raspberry Pi has some competition, in the shape of the BeagleBone Black. I thought it might be useful to compare these two boards and highlight their relative advantages.
Both boards are Linux-based single board computers about the size of a credit card. You can attach monitors, networks, keyboards and mice to both of them and both of them have GPIO connectors that allow you to attach and control external electronics. This makes them suitable for all sorts of DIY projects, from
This is a review of the Quick2Wire Port Expander Combo kit and the Quick2Wire Analog Board. Both kits can be bought from a variety of sources, including CPC and SKPang in the UK.
The picture above shows the main interface board complete with ribbon cable for attaching it to a Raspberry Pi's GPIO header. On the right is the Analog board. The port expander board (included in the 'conbo' kit with the huge interface board, is a similar size and all the boards have 6 pin hea
The Leostick is an Arduino Leonardo compatible board from Freetronics.
There are a number of things that make this board a great deal more than a clone:Its smaller than the Uno / Loenardo sized Arduinos. In fact about the size of a USB flash drive.It has a USB plug built onto the PCB, so you can plug it straight into the side of your computer to program it. Or use an USB extension lead.It has a built-in RGB LED.Being a Leonardo type board means that you can have it emulate a keyboard and m
I thought I would share this little helper I have made to simplify using the Pi with jumper wires.
If you are using your Raspberry Pi with Breadboard, and you have lots of connections to make, then the Pi Cobbler from Adafruit is pretty neat. However, sometimes you only need to make a couple of connections and the Cobbler is overkill and a few Male to Female jumper leads will do just fine.
The drawback with using Male to Female jumpers direct onto the GPIO is that you then have to co
I have just finished a project with my son Matthew. We started it as something to do in the Christmas holidays. We decided to write a book on the Minecraft mod ComputerCraft. This extension to Minecraft allows you to do all sorts of really cool things with Computer Blocks within your Mincreaft world. These computer blocks can be programmed in the Lua language and can control things that move or lightup in the Minecraft world.
You can have computers, external monitors and you can eve
What a great combination! Raspberry Pi, Chronos watch, Servos and a Laser.
This is a real mash-up from two projects. One that displays accelerometer data from a Chronos watch, over its wireless link. The other project being the Adafruit tutorial on using their I2C servo controller.
I combined them to make a two-axis servo mounted laser that mirrors the movement of my arm wearing the watch.
The .NET Gadgeteer system has spawned a wide range of low cost and useful modules form places like GHI Electronics and Seedstudio.
I have a load of Gadgeteer modules, sitting in a cupboard, so I thought it would be good to see how hard it would be to use them with an Arduino. I decided to start with a nice easy one, this relay module from Seedstudio. It has four relays, each with an indicator LED.
The Gadgeteer modules are all connected by 10 way ribbon cable connectors
If you are an Arduino user, you may well have used a 16x2 LCD display. These displays require a pot to set the contrast. The Adafruit 16x2 OLED display does away with the need for this pot.
In all other ways it works just like an LCD 16x2 display and uses the standard LiquidCrystal library.
Its not that obvious from the photo above, but this display is lovely! The background is jet black under most lighting and the LED emissive display much clearer than the LCD equivalents.
Thanks once again to FabLabMcr I have used the laser cutter to make a 'Recording' light for my son's studio.
It was really easy to make. Its basically a red / clear acrylic sandwich with paper in the middle as the filling. The letters are in a stencil font that is cut from the red layer.
This is then screwed to the front of a wooden frame, that contains a main lamp holder with a 15W compact fluorescent in it. Holes are drilled into the top to let the heat escape.
I finally got chance to have a really good play with a Leonardo a few weeks ago. I was checking that the Arduino-based sections of 'Hacking Electronics' worked with the Leonardo as well as the 'standard' Uno.
The new book will contain about 25 sketches - well Arduino is just too useful not to include in the book. So, it was with some trepidation that I uploaded the first sketch. Some 24 sketches later, and I was a convert. In the end, everything worked, and with the appl
We were all planning what we could do to hack some electronics with our Raspberry Pi's even before they arrived, and a little help in accessing and using those pins on the GPIO connector makes life a bit easier.
In this review, I look at the relative merits of three prototyping boards for the Rasspberry Pi. I use the term 'Prototyping' to distinguish them from expansion boards like the Gertboard and Pi Face that have buffers, level converters LEDs and other electronics attached to them. Wh