It's All About Cars
Well, it's about electronics and software too, but mainly about cars.
Firstly, there is news about the City-El, my electric bubblecar. I wrote earlier about getting it through the MOT test and running it on a temporary set of batteries. I have now, with a lot of help from aminorjourney, purchased three new Crown 12V 105Ah batteries and installed them. Since then, I've taken the car to the charging points at Cabot Circus (twice), to the Tesco's in Bradley Stoke and to UWE. None of these trips have been long ones, so I still haven't determined the overall range. I've been monitoring the pack voltage fairly carefully, although I have now removed the Tandy multimeter that was fixed to the dash with Velcro. It was reading 0.6V too high at around 40V, which is enough to make it useless for the purpose of monitoring charge. If I can get it recalibrated, I'll reinstall it in the rear of the car, next to the charger's ammeter. I have a good circuit for an expanded scale (analog) voltmeter that would read 30-45V, so I may fit that, if I can find a good mounting arrangement. I'd also like to fit a charging indicator light and some night-time illumination for the ammeter. The high-level brake light continues to annoy, mainly by falling off.
As part of the stuff I'm doing for Dorkbot Bristol, I have connected a MIDI keyboard to my Linux machine, and a MIDI synthesiser module. It's a Roland CM-32L, which I bought at a car boot sale a few years ago. It turns out to have a good selection of rhythm sounds, which will be useful for the Dorkbot project.
One of the City-El trips was to Bradley Stoke, to collect a FreeCycle item: a set of PC speakers and sub-woofer. Now, I was told that it was broken, but the fault went deeper than I expected. First of all, the volume control for the subwoofer was broken -- snapped off at the PCB level. I fixed that by soldering six short wires to it and resoldering it to the PCB. Then, I found that the main on/off switch (on the main volume pot) was broken, so I by-passed that (it didn't actually switch the mains off anyway). Then, the pots were so worn that they acted like carbon microphones. But the most odd thing was that the sub-woofer just didn't respond to low frequencies. It peaked at about 75Hz, when tested with the fine HP 3310 Function Generator. I traced the circuit of the crossover filter and changed a pair of 0.068uF capacitors to 0.47uF, and suddenly it worked down to below 5Hz. That actual speakers seemed to be OK. The power amplifier chip turned out to be a Philips car radio amplifier.
Monday was mainly about making videos of electric cars, namely the Mitsubishi Miev. Quite by chance, we discovered an ideal site for a secret lair, not far from Chippenham and apparently abandoned. The gatehouse had a very derelict but distinctly 1930s look to it. There were vast areas of concrete, derelict industrial buildings and hints that it may have once been something to do with the water supply system. Once safely back in Bristol with the precious footage, we discovered that my recent Linux upgrade (to Slackware 12.2) had rendered my FireWire interface useless. This led to general gnashing of teeth and recompiling of all sorts of obscure packages. It's fixed now, though, and I'm about to embark on some soldering, while simultaneously recording every eighth frame of the video onto a DV file on the Linux filesystem. The result will, I hope, be a speeded-up version of the build process -- inspired by Mythbusters.
At UWE, I was given a batch of Acorn RiscPC Model 700 machines, with StrongARM upgrade modules. But they were all fitted with strong brass padlocks to keep the covers closed. Well, they looked strong but actually succumbed to drilling out really rather easily. Inside, they all have leaky clock batteries, but are otherwise OK. I've only tested one so far, but that one worked fine. Running it was a glimpse of a lost civilization from 1996...
Finally, yesterday I contacted the new Suzuki main dealer in Bristol and arranged to have the Cappuccino picked up (on Tuesday). So, today I fitted the new battery (I got that at the same time as the City-El batteries), put some petrol in, and started it up. Started first time, too! Again with help from aminorjourney, we cleaned the car, removed the cobwebs, pumped up the tyres and generally made it ready for its repairs. Having checked the MOT failure note, it turns out that the Cappuccino has been in the garage for three years, not two years as I first thought.
Firstly, there is news about the City-El, my electric bubblecar. I wrote earlier about getting it through the MOT test and running it on a temporary set of batteries. I have now, with a lot of help from aminorjourney, purchased three new Crown 12V 105Ah batteries and installed them. Since then, I've taken the car to the charging points at Cabot Circus (twice), to the Tesco's in Bradley Stoke and to UWE. None of these trips have been long ones, so I still haven't determined the overall range. I've been monitoring the pack voltage fairly carefully, although I have now removed the Tandy multimeter that was fixed to the dash with Velcro. It was reading 0.6V too high at around 40V, which is enough to make it useless for the purpose of monitoring charge. If I can get it recalibrated, I'll reinstall it in the rear of the car, next to the charger's ammeter. I have a good circuit for an expanded scale (analog) voltmeter that would read 30-45V, so I may fit that, if I can find a good mounting arrangement. I'd also like to fit a charging indicator light and some night-time illumination for the ammeter. The high-level brake light continues to annoy, mainly by falling off.
As part of the stuff I'm doing for Dorkbot Bristol, I have connected a MIDI keyboard to my Linux machine, and a MIDI synthesiser module. It's a Roland CM-32L, which I bought at a car boot sale a few years ago. It turns out to have a good selection of rhythm sounds, which will be useful for the Dorkbot project.
One of the City-El trips was to Bradley Stoke, to collect a FreeCycle item: a set of PC speakers and sub-woofer. Now, I was told that it was broken, but the fault went deeper than I expected. First of all, the volume control for the subwoofer was broken -- snapped off at the PCB level. I fixed that by soldering six short wires to it and resoldering it to the PCB. Then, I found that the main on/off switch (on the main volume pot) was broken, so I by-passed that (it didn't actually switch the mains off anyway). Then, the pots were so worn that they acted like carbon microphones. But the most odd thing was that the sub-woofer just didn't respond to low frequencies. It peaked at about 75Hz, when tested with the fine HP 3310 Function Generator. I traced the circuit of the crossover filter and changed a pair of 0.068uF capacitors to 0.47uF, and suddenly it worked down to below 5Hz. That actual speakers seemed to be OK. The power amplifier chip turned out to be a Philips car radio amplifier.
Monday was mainly about making videos of electric cars, namely the Mitsubishi Miev. Quite by chance, we discovered an ideal site for a secret lair, not far from Chippenham and apparently abandoned. The gatehouse had a very derelict but distinctly 1930s look to it. There were vast areas of concrete, derelict industrial buildings and hints that it may have once been something to do with the water supply system. Once safely back in Bristol with the precious footage, we discovered that my recent Linux upgrade (to Slackware 12.2) had rendered my FireWire interface useless. This led to general gnashing of teeth and recompiling of all sorts of obscure packages. It's fixed now, though, and I'm about to embark on some soldering, while simultaneously recording every eighth frame of the video onto a DV file on the Linux filesystem. The result will, I hope, be a speeded-up version of the build process -- inspired by Mythbusters.
At UWE, I was given a batch of Acorn RiscPC Model 700 machines, with StrongARM upgrade modules. But they were all fitted with strong brass padlocks to keep the covers closed. Well, they looked strong but actually succumbed to drilling out really rather easily. Inside, they all have leaky clock batteries, but are otherwise OK. I've only tested one so far, but that one worked fine. Running it was a glimpse of a lost civilization from 1996...
Finally, yesterday I contacted the new Suzuki main dealer in Bristol and arranged to have the Cappuccino picked up (on Tuesday). So, today I fitted the new battery (I got that at the same time as the City-El batteries), put some petrol in, and started it up. Started first time, too! Again with help from aminorjourney, we cleaned the car, removed the cobwebs, pumped up the tyres and generally made it ready for its repairs. Having checked the MOT failure note, it turns out that the Cappuccino has been in the garage for three years, not two years as I first thought.