Electronics Blog

I have taken delivery of a 2nd solar cell. By coupling this with the other in series, the voltage will be doubled. This will be used to charge either 1 ot 2 AA/AAA batteries.

I think there are 2 problems with the Solar Powered Battery Charger. 1, it would only charge the batteries when the output voltage exceeds the joint voltage rating of the batteries, and 2, the output current is not limited. To solve 1, I plan on only charging 1 battery at a time so the output voltage only needs to be above 1.2 V. To solve 2, I will develop a current limiting circuit.

The circuit has been successfully implmented on the breadboard. Auch! The stripboard plan was implemented upside, so it didn't work!

As a step in finding the fault with the Electronic Dice I have decided to make a 555 Tester so the it can be eliminated as the source of the fault. All the 555 Testers I located on the internet seemed to be based on this design. I have breadboarded the tester.

I am not sure if the Solar Powered Battery Charger is working properly as batteries do not appear to be charged, and need to investigate and verify this.

I have assembled the circuit on the breadboard but (as usual) it doesn't work. I will need to do a thorough inspection and make sure there are no 'shorts' etc.

What this has done has prompted me to do some more in depth investigation of the 555.

The parts for the Solar Powered Battery Charger arrived with the parts for the Electronic Dice project.

The parts for the Electronic Dice project have arrived from Rapid.

I sourced some (10m) red 1/0.6 wire from Maplin.

I have decided to undertake the Electronic Dice project and I have also ordered the parts for this project from Rapid.

The revised order for the projects is:

I have found the Electronics Club very useful.

I have also breadboarded the CDU project and it is ready for testing. I need to get some 1/0.6 red wire for the lead from the PSU, the switches and solenoids.

My suspicions about the capacitor were partly right. One of the solder joints at its leads was shorting and making the circuit fail. A little resoldering eliminated the short and the project WORKS!

I think I have traced the fault to the capacitor or the switch. The LEDs are wired correctly. If I short the CK to R1 (87K) bypassing the capacitor, I can get a debounced switch which flips the LEDs in an unstable way.

Yay, I have finished the soldering for my 1st project, including the repair. Checked the circuit as best I could with the multimeter. Hooked it up to a battery, and lo ... it didn't work. One LED lights up but the push-button doesn't switch the circuit to the other LED. Now starts the troubleshooting.

Well, the Fume Extractor is very good at sucking the solder fumes away. On its 1st outing it certainly did the job.

The Solder Remover wick took a little while to get used to, but it does the job very well.

I soldered 3 of the 4 resistors denoted in the circuit diagram into place. The 4th will go in next time.

I dug out the multimeter and did some continuity testing. I found one joint that is setting up a ciruit with an adjacent joint on the next track. I will need to repair this.

The Fume Extractor has arrived, along with the Solder Remover wick and a tube of Heatsink Compound (for a PC that I am rebuidling). I won't be able to test the Fume Extractor until the weekend.

I have ordered a Solder Fume Extractor and a reel of Solder Remover wick from Rapid. Hopefully this will enable me to complete the first project!

I took a picture of the solderless breadboard with the FlipFlop project in place. Tthe start of adding the pull-ups and pull-downs for the unused pins on the 74hc14 are visible.

I am not sure how it ended up so out of focus as I used a tripod and timer delay to take the picture, so no human hand interferred with it. I will need to check the lens and make sure it is clean and free of finger smudges.

I use a lot of AA and AAA batteries. I switched many years ago to using rechargeable batteries, but now I am investigating charging the batteries 'for free' with a Solar Powered Battery Charger. I believe the +ve lead from the solar panel goes to the -ve terminal of the battery and vice versa. A progression of this might be to implement a solar powered PDA charger. The parts I need are available from Rapid but they will have to wait until I have a big enough order.

Getting the capacitor pack was probably not such a good idea as the capacitances are so low.

Of course I produced the mirror image of what I need with the new piece of strip board. Arrghh!. Easily done with stripboard.

I managed to clean the solder swamp up, so I am using the original stripboard! There is a 'dry joint' that I need to attend to, but apart from that the connecting wires are in place. Test for shorts and adding the resistors next.

Getting the hang of the soldering, and I have still to experiment with the 1mm bit.

The stripboard cutter is a superb little tool.

I decided to start again with another piece of stripboard.

Moved the collars down the bits, but I needed to use a lot of force and 2 pairs of pliers. As a result, the shaft of the 2.3mm bit is a bit mangled.

I have also tried get the bit nice and shiny, but it keeps gunking up. I will get some bit cleaner.

I also managed to swamp the striboard with solder! Arghh! I will need to get some desoldering equipment.

For the FlipFlop project, I swapped the 74hc04 for a 74hc14, used a 87K resistor, and swapped the capacitor for a 1uF electrolytic capacitor, and the FlipFlop project works on the breadboard! It wasn't cleanly switching before. I am checking tieing off the unused pins and transferring it all to a stripboard.

I have used the new 2.3mm soldering iron bit. They acquire deposits quickly! I have manged to keep the blade of the bit nice any shiny, but the tip has acquired some deposit, which I will try to clean off using flux and shock. I also learned that the collar is very important to stop the bit falling off the iron, so I will be trying to manipulate this with pliers and improve bit grip.

The 2.3mm bit seems too big for stripboard soldering, so I will try the 1mm bit.

The second consignment of parts has arrived, so in theory I have all the parts to work on the FlipFlop, the CDU, the +5V Regulated Power Supply, and the Logic Probe. The first opportunity to look at any of this will be Sunday. Boxes and cases for all these parts (apart from the CDU) have not been considered yet either. I have been considering another project, which is the Dice project usig a 555 timer.

The order of projects is:

I wonder what the market is for a very basic components internet vendor, that sells like 5 resistors or 1 transistor. Obviously, the cost of postage is the underlying factor. And it certainly isn't a "make loadsa money" idea.

The bits from Maplin fit the iron, are smaller than the existing bit, but i reckon that is because the existing bit is a 3mm bit. I'll try them out soon.

I have been playing with the FlipFlop circuit on the breadboard, and I am now awaiting delivery of a meatier capacitor for the debounce circuit.

I have ordered the parts from Rapid to make the +5V Regulated Power and the Logic Probe, and the transistor needed for the CDU!

The existing bit has cleaned up a little, but I am still opting for the replacement bits from Maplin.

Maplin Electronics have replacement bits for the Antex C soldering iron locally. Spending £7 for the bits instead of £15 for a new soldering iron makes some sense.

The parts have arrived today from Rapid.

The 2mm plugs are too small, and the 4mm plugs are too large. The soldering iron bit is too large, the old one is so caked with residues that it does not pass heat properly anymore and is not tinnable. I was gambling that an Antex CS bit would fit an Antex C iron. I was wrong. And to top it all off, I forgot to order the transistor used in the CDU. Doh!

I will have another go at cleaning the existing bit, and if that fails I will get a CS soldering iron. It is a bit more powerful being an 18W iron instead of the existing 15W iron.

I am also trying to generate a jpeg image of the schematic for the FlipFlop project. I have all the parts to progress this project now.

The parts to entertain and educate the children have all arrived.

I have ordered the parts necessary to build the CDU and restart the FlipFlop project from Rapid Electronics.


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Last updated - 16th December 2007
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