Member postings for James Alford

Good evening.

I am getting muddled, so should appreciate any help, if possible.

If an engine and gearbox which is normally matched to an axle with a differential with a ratio of 3.23 and 10" wheels (tyre OD of 19.1" is fitted to an axle with a differential with a ratio of 5.25 and 17" wheels (tyre OD of 25.6", what is the likely result?

I cannot work out whether the larger wheels and 5.25 differential will result in the engine over-revving, under-revving or whether there is likely to be little difference.

Any suggestions?

Regards,

James.

My point entirely for buying the new unit. My previous machine is a twenty year old, ten litre SIP Tornado unit that can wake the dead.

I tested the Orazio today with my blow torch, for which I primarily bought the compressor. It lasted much longer than the older compressor before coming on (understandable), and refilled with the blow torch still running in much the same time as with the older unit. I have an in-line pressure regulator on the airline for the torch.

I also tried using a small LVLP spray gun with it, spraying water. Not surprisingly, the compressor cut in pretty quickly, although with no pressure regulation at the moment, that might be aggravating matters.

Throughout this, I could listen to music playing without problems, even with the compressor running.

James.

Edited By James Alford on 15/04/2018 18:08:05

Michael W,

I bought a collet chuck from Arc Euro and needed to make a back plate for my lathe. This thread covers it and might help. I had real trouble getting rid of run-out initially, but it was my technique and skill, not the collet chuck at fault. I did get run-out down to 0.0005", a mere flicker on the needle.

http://www.model-engineer.co.uk/forums/postings.asp?th=120081&p=2

James.

Having had enough of being deafened by my compressor, I splashed out and bought one of these from Amazon.They do a 9 litre version for about £90.00 and 24 litre version for £120.00 Whilst I have yet to hook it up to any tools, I have run it to test it for noise levels.

If anyone is after an affordable, quiet compressor, I can recommend it. You can hold a conversation at normal levels with the machine running next to you.

James.

Edited By James Alford on 14/04/2018 18:01:13

Dave,

I have also come to the conclusion that I am better off with a transformer and worrying about saving power at a later stage. I should have to reduce consumption dramatically to make much practical improvement, especially once the solenoids are in the circuit instead of LEDs.

I am already using an RTC to keep the time, the RTC module having its own battery. The Uno interrogates the RTC for timings, with the Uno controlling the functions at intervals determined by the RTC.

Neil,

I shall have a look at the Sparkfun article. I have used a few ideas from that site, but not on this aspect.

The circuit that I have built uses a LED display to show the time, with a couple of press buttons wired in to advance and retard the time. This will be used to set up the time whenever required, rather than plugging the final clock into a laptop and setting the time via the IDE. I shall arrange for the display to switch off when not required. Ultimately, I should like the finished device not to require a computer to be viable.

Again: thank you all for the help and suggestions.

Regards,

James.

Edited By James Alford on 13/04/2018 07:15:38

An update on battery life.

For what it is worth, using four alkaline 1.5v C cells to power the Uno, a LCD clock display and LEDs flashing each second, minute and hour, along with a flashing LED for quarterly and hourly chimes, the system became unstable after seven days. The chime LEDs are disabled automatically at night.

Whilst I know that this could be improved by following the suggestions given here, I think that I have concluded that I shall need to use a transformer for the final device, reserving a battery for back-up, should the mains go off.

Thank you for your advice.

James.

True, but it would not be the design that I hope to create.

I tested the current draw again today with an AVO with a large, clear dial. It showed 45ma, rising to 55ma when an LED flashed.

James.

Edited By James Alford on 06/04/2018 12:35:10

Good morning.

I have just come across this, having read another of Magpie's post and am really impressed by the quality of work and the overall design.

But......OK. I am happy to ask the question. How does it work?

Regards,

James

Edited By James Alford on 06/04/2018 07:39:10

John and Dave: Thank you for the advice on buck convertors. I shall look into this.

John: have removed two batteries, running it now with six volts. This has reduced the current draw to between 35ma and 75ma. I shall check again at the weekend, though. My everyday multimeter has a small dial and is hard to read at the best of times. It is most useful for estimating than measuring. I have a large AVO tucked away and shall check with that.

Dave: I have a number of LEDs fitted, only one flashing at a time. One is triggered through a transistor, the rest straight from the pins. They all have resistors fitted, but I think only 100 ohm. Perhaps I should be increasing this, at least whilst using LEDs to test the circuits.

Magpie: I had a quick look at your LED clock thread. It looks really impressive and I shall read it in detail. Thank you.

Regards,

James.

Edited By James Alford on 06/04/2018 07:10:50

Good morning.

Last night, I set up my Uno and clock circuitry to run on six alkaline C cells. I measured the current draw: 60 milliamps when only the LCD was running, rising to 150 milliamps when a LED triggered. Disconnecting the LCD, which is only used to set the time, reduced the draw by a couple of milliamps.

By my estimation, this will give me a running time of about five and a half days at the outside for just the resting circuit. Add in the additional drain for all of the LEDs (currently one per second, minute, hour, am or pm indicator, day of the weeks indicator and two for the quarter and hourly strikes and chimes), and I shall be lucky to see a few days before the batteries go flat. I used the LEDs, which will be replaced in time with the solenoids, to test my progamming, Oh, well, time will tell.

Somehow, I think that I shall need to use an external power supply after all, reserving a small nine volt battery as a back up, should the mains become disconnected.

Regards,

James.

Edited By James Alford on 05/04/2018 07:25:05

Thank you, again, for the ideas and suggestions. I shall have a look at the Nano, as suggested. I have the Uno simply because it was a present, rather than by active choice.

I am going to try a practical test to get some idea of likely battery life span. I have the Uno wired up to a LCD clock display and LEDs flashing instead of solenoids operating: as an interim I plan to buy some small three volt relays to replace the LEDs as I hope that these will approximate more to the current draw of a small, three volt solenoid. I shall then run it from six C cells and see how long it lasts. I can also use my multi-meter to measure current usage.

I have plenty of time to test it as I am still working on the actual clock mechanism's design.

Regards,

James.

Thank you for all of your replies, which I need to digest properly yet. A couple of quick replies, though.

Bazyle.

Someone else made this observation as well. I have considered a low-RPM motor like the one below. It claims to draw 30ma at 1.5v giving 25rpm. With a cam and microswitch, it would only need 1 revolution per operation.

Not yet, Dave. I was thinking of making my own, following the details in this clock (page 12), which is what set me off in this general direction in the first place. **LINK**

Kind regards,

James.

Good afternoon.

I am slowly designing a clock that will be controlled by an Arduino Uno and operated by a series of solenoids. To avoid trailing cables, I plan to power it with batteries. I have no idea yet what current it will draw, so plan to incorporate as much "power" as reasonable into the space for the batteries.

Assuming the same circuit and operating conditions, and aiming for a 9v supply, which of the following configurations is likely to last the longest, at least in theory? I know that different cell types discharge differently, but do not know how this affects things in practice.

6 alkaline D batteries (1.5v 12,000mha) in series to give 9v

6 alkaline C batteries (1.5v 8,000mha) in series to give 9v

6 lithium AA batteries (1.5v 1,200mha) in series to give 9v

6 alkaline PP3 batteries (9v 600mha) in parallel to give 9v

6 lithium PP3 batteries (9v 1,200mha) in parallel to give 9v

Any guidance would be appreciated.

James.

Thank you, Geoff. I have just replied.

Regards,

James.

Good morning.

A friend runs a firm that services the Austin 7 fraternity. Three of his products are an alloy engine pulley, modified manifold nuts and a strange, half-round bar with holes drilled in it. His current supplier is, I believe, retiring and he is looking for someone else to take on the work.

If anyone is interested in some small batch work, requiring just milling and turning, please let me know. I can send you the drawings and details of the products, and his contact details for you to discuss it directly with him.

Kind regards,

James.