Controlled shutdown duration test of Pi model A with 2 cell lipo

 Electronics, Input and Output, interfacing, python programming, raspberry pi, Raspberry Pi Hardware  126 Responses »
Mar 052013
 
Controlled shutdown duration test of Pi model A with 2 cell lipo

Lithium polymer batteries are light and powerful, but they can’t be run completely flat or they are ruined. I’ve been using them for several years to fly model planes, so I have plenty of them around. I’ve also been using them at Raspberry Jam meetings to power some of my Pi demos. I thought it would be fun to make a circuit so the Pi could monitor its own battery voltage. I used an analog to digital converter (mcp3002) and had the Pi check the battery voltage every minute and shut down when the battery […more…]

Using a Wii controller with your Raspberry Pi, Gertboard, Bluetooth and Python

 Electronics, Gertboard, Input and Output, interfacing, python programming, Raspberry Pi Hardware  37 Responses »
Feb 122013
 
Using a Wii controller with your Raspberry Pi, Gertboard, Bluetooth and Python

Matt Hawkins from Raspberry Pi Spy has done the leg-work enabling Pi users to use a Wii controller – along with a Bluetooth USB dongle to send inputs to the Raspberry Pi. It uses a Python library called “CWiid” (I imagine this is pronounced “seaweed”). This is awesome because the Wii controller has 11 different digital inputs. When you consider combinations of inputs, that gives you a lot of extra possible “input commands” to play with. Theoretically*, with 11 buttons, there are 55 different 2-button combinations (11C2). That should be enough for most uses. If […more…]

RasPi RepRap 3d printing on the Raspberry Pi

 Electronics, interfacing, Raspberry Pi Hardware  9 Responses »
Feb 012013
 

Alex Gibson, co-host of the Oxford Jam impressed us all with his RepRap 3d printer controlled by a Raspberry Pi. I hadn’t seen one of these up close and personal before. I’d really like one now, but I have a feeling it requires a large investment in time to build, calibrate and use. Check out the 4 minute video. Most impressive indeed! :) Background Alex told us he’d joined the Thames Valley build group, which is a bunch of people who get together to help each other make RepRaps. The reel of poly-lactic acid (PLA) […more…]

fantastic sounding raspberry pi solenoid sequencer

 Electronics, Input and Output, interfacing, python programming, Raspberry Pi Hardware  4 Responses »
Jan 302013
 
fantastic sounding raspberry pi solenoid sequencer

I went along to the Oxford Raspberry Jam last night at RS HQ. There were several impressive demos. But this one was definitely the best sounding of the lot. Peter Andrew has put together a solenoid sequencer (a bit like a drum machine) which is driven by a python script on a raspberry pi. He’s also written an android app to program the beat with his Nexus 7 tablet. Solenoids are pulsed to make them strike a tin can, a jar lid, a small glass jar and a saucepan lid. The saucepan lid sounds wonderful. […more…]

How to make a RasPi into a NoSPi

 Electronics, Input and Output, interfacing, Raspberry Pi Hardware  8 Responses »
Jan 282013
 
How to make a RasPi into a NoSPi

I’ve been doing some prototyping of a new Pi related hardware project I’m working on. I’m not ready to let on what it is yet, but it involves a potentiometer. The pot in question is one of those that you need a small screwdriver to turn. So here’s what happened. I left the screwdriver standing in the pot like this… …and it fell, shorting something out. Not sure exactly what, but it may have bounced on a pin carrying 12V for a motor. What I do know for sure is that an ic chip that […more…]

V2 Gertboard photos and initial impressions

 Gertboard, Input and Output, interfacing, python programming  12 Responses »
Jan 242013
 
V2 Gertboard photos and initial impressions

My V2 Gertboard showed up today. I promised some photos yesterday, so here they are, along with some first impressions… Main visible differences from V1 are: CE and FCC marks Different fuse holder Different motor controller chip – surface mount All ICs are soldered directly to the board apart from the ATMega, which is socketed leds are surface mount there are pull-up resistors on the buffers the buttons are surface mount the DAC chip is teeny weeny and surface mount the regulator is surface mount The jumpers with grippy extension are very practical But the […more…]

V2 Gertboard Officially Adopts my Python Test Suite

 Gertboard, Input and Output, interfacing, python programming  24 Responses »
Jan 232013
 

I’ve been sitting on this for a while, but I’m now delighted to announce that the manual for the new Rev 2, fully assembled Gertboard, which officially went on sale yesterday, includes full documentation of my Python Gertboard Test Suite. I wrote the Python-specific sections and Myra’s done a great job of weaving them into the fully updated manual. You can download the new manual here You can download the Python Gertboard software here. The Python software was fully tested by Myra before Christmas on the only Rev 2 Gertboard in existence at the time. […more…]

The Self-resetting Raspberry Pi

 Input and Output, interfacing, Linux usage, python programming, raspberry pi, Raspberry Pi Hardware  13 Responses »
Dec 212012
 
The Self-resetting Raspberry Pi

Recipe for auto-reset Pi. Take one Rev 2 Raspberry Pi, a few carefully selected slices of fresh Python, one GPIO port (’25 vintage, preferably), one relay (a twin pack is OK, but not AA), one Darlington array (leave the spikes on), a sprinkling of mixed wires and arrange it all carefully with a breadboard. It should end up looking something like this… I decided to take the P6 reset header one step sillier further. Just for fun. ;) The idea here is to use one of the Pi’s own GPIO ports to switch a relay […more…]

Using a Darlington Array as an inverter for reverse polarity RGB leds

 Electronics, Input and Output, interfacing, raspberry pi  2 Responses »
Dec 142012
 
Using a Darlington Array as an inverter for reverse polarity RGB leds

RGB LED RIP :( Last week, I was wiring up a demo with a three colour RGB LED, and accidentally wired the pin for the red component straight to 3V3 (plugged it into the wrong port). It went “crackle” and then turned black. Ooops. Now it’s a GB LED, the red’s a gonner. :( “Dammit. I wanted to shoot a video with the Quick2Wire Interface running the RGB LED. It’s 7pm and if I order some they won’t be here for two days.” “Oh I know. I’ve got an RGB LED in an old Christmas […more…]

Quick2Wire Pi Interface Board Beta Review

 Input and Output, interfacing, python programming, Raspberry Pi Hardware, Review  6 Responses »
Dec 072012
 
Quick2Wire Pi Interface Board Beta Review

Quick2Wire Pi Interface (Beta) review The Quick2Wire Pi Interface Board is a new interface board for the Raspberry Pi. It’s not yet released, but it is in Beta. I managed to get hold of one of the Beta kits for research and review. :) I also had a chat with Romilly Cocking, Director of Quick2Wire (more on that at the end).   So, What’s in the kit? 1 PCB 1 Ribbon cable (nice colours) 4 jumpers 11 assorted headers 2 FETs 1 tantalum capacitor 1 LED 1 push button 3V3 voltage regulator 1 diode array […more…]

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