Around about this time three years ago, I bought and installed five EasyN pan-and-tilt ip cameras to keep an eye on various viewpoints of our houses in the UK and Poland. I think they were about £45 each on Amazon. They’re not too hard to set up and they work tolerably well. The main downside is that their resolution is only 640 x 480 pixels, which is not enough to read a car numberplate from across the street. It’s fairly poor resolution, but you can see something. The colours are a bit washed out too […more…]
I’ve been using lithium polymer (lipo) batteries since 2006, when I nervously shelled out £30 for a 3 cell 1600 mAh 10C HiModel lipo to power my EasyStar RC plane. I also spent about the same on a charger and balancer for it. Thankfully, all these things have come down a lot in price since then. I don’t think I’d expect to pay much more than £10 for an equivalent battery now. Typical lipo batteries for large devices have multiple cells. A lipo cell has a no-load resting voltage of 4.2 V when fully charged […more…]
I’d never done graphing on the Pi or in Python before, but for my KickStarter tracker I wanted something that… was web based would work in Python had decent instructions I could get going with fairly quickly I’d seen Rachel Rayns tweet about using plot.ly for graphing the temperature output of her Chef’s HAT sous vide cooker. I know Rachel loves “human readable instructions”, as do I. So I thought there was a good chance the plotly documentation was good. I decided to give them a shot. Sign Up For An Account The first thing […more…]
In a recent post, I showed you how to hack the HDMIPi power switch so that you can turn the screen on and off from the Pi. But no sooner had I done that than my friend Peter Onion, wondering if there was a way to detect if the LCD is on or off in case it gets “out of sync”, tweeted this… @RasPiTV Is there a switched 3v3 supply to the LCD pannel ? Wire that to a GPIO input pin ? Or can you test monitor "on" via hdmi ? — Peter Onion […more…]
The HDMIPi driver board is a fairly complex design. I didn’t design it, although I did have some input into the feature list. I don’t fully understand how it works (something to do with the magic white smoke in the chips, I think), but I have messed around with it probably as much as anyone. Recently, several people have been asking if we can switch HDMIPi on and off programmatically from the Pi. Göran Roseen wants to be able to do it with this HDMIPi based clock… @Raspberry_Pi wall clock with go-to-school indicator that goes […more…]
From observation of the computer industry going back to 1987, when I did a pre-university year at IBM Scientific Centre in Winchester, it seems that the very brightest and best programmers (software creatives) are often not very good at or not very keen on documenting their work. I think the reason for this is often misunderstood. Poor documentation is a source of great consternation in the world of Linux. In fact it’s a large part of the raison d’être for RasPi.TV. We, the users, often feel that the geniuses who write awesome software can’t be […more…]
Today the CamJam Edukit 2 is being launched at the first Cambridge Raspberry Jam PiWars event. I’ll be judging the smallest robot and the best non-competing robot categories at PiWars, but today’s blog is about the kit. This is the second kit in the series, which adds some sensors (temperature, light and PIR) into the bundle. The full kit contents is shown and described below. What’s in the Kit? A 400 point bread board including dual power rails Immersable DS18B20 temperature sensor Light Dependent Resistor (LDR) Passive InfraRed (PIR) sensor Piezo buzzer 4 male-male blue […more…]
So this is part 2 of the KickStarter Tracker in Python. (If you’ve not seen part 1 yet, that’s here.) We got the basics working last time. Now we want to make it look nicer, add more campaigns and have it running continously. So first let’s see about how we can introduce some colour… Adding Colour To Console Output There may well be more elegant ways to get the job done here, but I found a way that uses what’s called “escape sequences”. These are basically codes which can be used to modify the characteristics […more…]
Ever since the HDMIPi KickStarter I’ve been very interested in watching the progress of other campaigns. I’m following four or five Pi-based campaigns at the moment. Are they going to make it? Are they not? It’s nice to keep an eye on things. But monitoring more than one or two wastes a lot of time. Wouldn’t it be nice if I could have a little computer and screen set up so that it checked these campaigns, say, once a minute, and reported on how they’re doing? I know there’s a decent Python library called urllib2. […more…]
A Raspberry Pi SmartWatch? You’re kidding me right? Errrm. Yes. I mean… Well… This has a lot of the functionality of a smartwatch, but it wasn’t built for that purpose. It’s a little big, for starters. Let me back up and explain. Last week, Apple released photos of their new smartwatch. Twitter, Google+ and every social network was awash with photos, comparison photos, criticism, analysis and good old-fashioned Apple-hating. By Thursday I was rather bored of it all, so I decided to make a joke tweet. I had this rather large Vacuum Fluorescent Display (VFD) […more…]