Bob WB4APR (yes, that Bob) has very helpfully provided the pinout of the RJ45 (okay, 8P8C) connector on the TM-D710 display head. It shows that pin 6 is ground and pin 7 is +10V. This is a handy place to leech a few tens of milliwatts for the GPS receiver.

I decided that the easiest way to get access to the +10V pin is by repurposing a RJ45 Y adaptor. Apparently these splitters are sometimes used in ISDN installations. I bought mine from Maplin for £5.99.

The Y adaptor is very simple but the fact it’s already wired makes things easier.

The male end of the adaptor isn’t ideal for soldering but a little bit of work with a craft knife exposes the contacts enough to solder wires into them. Because the result is a bit fragile, I decided to cover the solder joints with epoxy. There are better adaptors that would be easier to tap into.

The GPS requires a 5V power supply. I wanted to make sure the system draws as little power as possible, so I used a Recom R78 series switching DC-DC converter from Rapid. The R78 is a small self-contained device that’s pin compatible with the 78xx linear regulators so it’s trivially easy to use. I decided to add an optional input capacitor and blocking diode for extra protection. The whole assembly was then secured onto the Y adaptor with epoxy to minimise mechanical stress.

All internals of the GPS receiver. The 2.5mm stereo jack is wired according to Kenwood’s instructions (page APRS-2).

I happened to have a suitable plastic box for the parts. The rectangular cutout is made with a craft knife. All parts are installed in the box with double-sided foam tape.

I made two short (~10cm) cables to connect the GPS to the display head, a 2.5mm stereo and a RJ45. Both are wired straight through. I’m planning to replace the jack lead with one with 90 degrees angled jacks for neatness. The box is attached to the back of the display head with velcro. The fact that the receiver antenna sits vertically does not seem to matter.

The GPS sits neatly behind the display head.

The +10V is supplied even when the radio is off. In the off state the rig seems to draw about 40 mA of current from the battery. Some of this is for the standby state of radio and some, probably most, is for the GPS. Overall that’s a negligible amount so I can just leave the GPS on all the time. This is good as the module seems to default to 19200 baud if left unpowered for a long time. The Kenwood only supports baud rates up to 9600, so I had to change the baud rate using the serial terminal on my computer and a suitable interface cable.

I won’t comment on the bogosity of Valkee’s claims. I did, however, decide to see how cheaply I could build something similar to their £185 device.

My headset isn’t the same as Valkee’s. Theirs seems to use fiber optic, presumably to keep the size and temperature down. Mine uses ultra-bright LEDs. Their’s has a fancy timer. Mine doesn’t. Theirs has a rechargeable battery. Mine draws its power from a USB socket.

On with the show!


The LED dimmer uses a headphone volume control (from Maplin, although cheaper elsewhere) as it provides a handy stereo dimmer in a neat case, and with a suitable 3.5mm socket already included! I replaced the 3.5mm jack with a USB A plug so the dimmer can draw power from any USB port.

The insides of the dimmer are simple. A couple of simple modifications will be needed to make them drive the LEDs.

This is the underside of the dimmer circuit. I had to cut a couple of traces to turn it from a headphone volume controller into a LED controller.

The LEDs run off 3 volts (I think). A couple of resistors in series with the dimmer limit the maximum current through the LEDs.

The 3.5mm jack is replaced by a USB A plug. This provides an easy 5V supply. If I’m not near a PC, I also have a selection of batteries and power supplies with a USB socket.

This is the dimmer put back together. Small and neat, no?

The earphones cost a couple of pounds on eBay. They’re made of metal and are surprisingly well put together. I tried to choose a model which looked like it could be taken apart easily. This took a bit of prying and twisting (which scratched the cases a bit) but eventually they came apart just fine. I’m sure the sound quality is pretty poor but we’re taking the speakers out so it doesn’t matter.

I ripped the speaker elements out and fitted ultrabright white LEDs in their place. The LEDs are glued into place with epoxy. Because the phones are made of metal, I insulated the LED leads with some heatshrink.

The earphone leads are soldered into the LEDs.

The earphones are glued back together with epoxy. The rubber tips are still out in this picture.

The phones fully assembled and working. The rubber tips fit around the LEDs, with the lights protruding a little. They are fairly comfortable in the ears. The dimmer gives a good range of brightnesses. In this picture they are quite dim. At their brightest, they really are quite bright.

This is the bath. I use two plastic boxes from Wilkinsons, one inside the other, to give a degree of insulation. The immersion heaters and the Pt100 thermometer probe are clamped between two pieces of plexiglass. I keep the lid on when the heater is on. This is a temporary arrangement until I get better heater elements. I will probably attach these directly to the lid.

My first pump got a bit hot and gave up the ghost, so it doesn’t feature in these photos. A replacement has been ordered.

Front view. The PID controller has just been switched on. It’s a Chinese REX-C700, apparently a non-pin-compatible fake of a Japanese controller of the same model number. The enclosure happens to be such a good fit that the controller doesn’t move at all between the box top/bottom and the enclosure’s screw posts. The power switch is at the top.

Rear panel. On the bottom left is the fused input. On the bottom-right is pump output, always on when the switch (on top of the controller) is on. Top-right is the heater output, controlled by the PID driving a 25A solid-state relay. Top-left is the thermometer input.

Building Instructions

These instructions are work in progress. I intend to amend and improve them soon, including adding pictures and circuit diagrams. Meanwhile, comments and questions are welcome.

This project should not be attempted by inexperienced DIYers. In fact, it should probably not be attempted by anyone. Done incorrectly, there is a very real risk of electrocution. These instructions give a very broad overview of the building process; do not expect to see every step described in detail (or correctly).

Right. With that out of the way, let’s crack on.

Bill of Materials

• 2 x REWIREABLE CEE22 CABLE PLUG, Rapid item 23-0120.
• SNAPFIT 4.8MM PLUG, Rapid item 23-2101.
• 2 WAY PUSH FIT IEC SOCKET, Rapid item 23-3107.
• LIGHT GREY ABS BOX 190 X 100 X 80, Rapid item 30-1498.
• SHEET OF 25 22.0 X 10 BLACK FEET, Rapid item 31-0465.
• DPST illuminated rocker switch, Maplin item GU55K.
• 3-pole locking chassis plug and line socket, Maplin items FK23A and FM51F.
• PID controller, eBay. I bought this one.
• Solid-state relay, eBay. I bought this one.
• Stainless steel immersion heater, 1 kW (search eBay for ‘tauchsieder’, German for the heater, in EU).
• Pt100-type thermometer probe, eBay. I bought these.
• Aquarium powerhead, eBay. I bought this one.
• Really Useful Box, 19XL (like 19l but with taller lid), eg. From Ryman.
• Fuse, 5A, fast blow, for the IEC inlet.
• Sheet of perspex, 3mm(?) thick.
• Spade crimp connectors, eg. Rapid item 33-1053; Eyelet crimp connectors.
• Cable ties.
• M3 screws and nuts.
• Bicycle inner tube.

Instructions

1. Start by modifying the dual-outlet IEC socket. We want to control each socket output separately, so they need separate live connections. Cut the ‘live’ metal strip into two and bend the strip so both sides can accept a spade connector. The ‘neutral’ strip can be left unmodified.
2. In the enclosure rear panel, cut suitable holes for the IEC sockets. The holes are probably easiest to cut in the edge of the panel as seen in the picture. Drill a hole for the 3-pole chassis plug. Cut two strips off the front panel to fit the PID controller. Cut a hole in the top for the switch.
3. Mount the IEC sockets and power switch in the enclosure. I used liberal amounts of epoxy glue to fix the IEC sockets in the panel. Because the panel is quite thick, I needed to trim the IEC sockets a bit to make them fit.
4. Using mains leads of suitable length with spade and eyelet crimp connectors, wire up the sockets, switches, PID controller and SSR. Wire both live and neutral from the power inlet through the switch. Be sure to connect the power switch the right way around; if it’s the wrong way, the neon light is on all the time. If it’s the right way, the light goes out when the switch is off.
5. Cut a suitable length (no longer than necessary) of the shielded thermometer probe cable off the probe assembly and use it to connect the 3-pole chassis plug into the PID controller. Choose some suitable wiring order; I wired the common lead in the middle pin. Attach the chassis plug into the enclosure.
6. Attach everything in the enclosure. I used some double-sided tape to fix the SSR to the side of the enclosure, as well as to keep the PID controller in place. The controller came with a couple of clamps which I used to tighten it against the front of the enclosure.
7. Close the enclosure. Attach rubber feet.
8. Cut a strip of perspex about 5 cm in height. I did this by first scoring the sheet several times on both sides using a ruler and a craft knife, then clamping it between the floor and a metal sheet and bending until the strip broke off. Done correctly, this leaves a neat clean edge.
9. Attach the thermometer probe and heater element to the perspex strip. I did this by first stretching a short piece of bicycle inner tube around the heater handle and the thermometer probe to provide an anti-slip surface, then drilling a couple of holes in the sheet and putting cable ties through the holes and around the probe and heater.
10. Attach the perspex strip to the box. I can think of a couple of ways of doing this. I decided to bend the ends of the perspex sheet into a 90-degree angle (using a clothes iron to warm the perspex and make a sharp bend) and then attaching the strip in the box with screws. Alternatively, you could just use cable ties.
11. Replace the pump and heater element power plugs with the IEC plugs. Solder the 3-pole line socket to the thermometer probe.

Done! (Kind of.)

Issues

• SAFETY: The device should never be left unattended.
• SAFETY: Combining mains power and water is always risky. A residual-current device adds a layer of safety and should be used at all times. Even if your home has RCDs, adding an extra in-line device can’t hurt. I bought one from B&Q for about £8.
• The immersion heaters are not designed to work for long periods of time. I have no idea how long they will last. Observe the minimum/maximum water level indicators and avoid splashing water above the high water level mark.
• Running the heater dry, even for a short time, would almost certainly break it. My heater has an internal overheating protection, a thermal fuse which cannot be changed. A good solution might be to add a float switch to make sure the box is filled with water. This could be added in the SSR control circuit.
• If the heater element is longer than the thermometer probe, there’s a risk of filling the box so that the heater is underwater but the thermometer isn’t. In this case, the heater would be on continuously, eventually boiling the water away. The best solution would be to get a longer thermometer probe.
• My first pump was a water fountain one, but it broke after a session at 85 degrees. I would not use the new pump at temperatures above about 68 degrees. Temperatures higher than that are normally used for things like fruit and vegetables where I suspect exact temperature control is less important, so you could just leave the pump out when cooking such things. There are some pumps designed to be submerged in caravan hot-water tanks that are rated for continuous operation at 70 degrees, but they require 12V and so may be less convenient.
• Due to the shape of the lid, condensed water on the lid drips down along the lid and out of the box. It would be better to add a seal of some sort on the lid to avoid this.
• At least in the UK, limescale is a big problem. In areas of hard water, a single 24-hour session can cause serious limescale buildup. I am currently experimenting with adding a small amount of washing soda in the water to prevent limescale buildup. If you notice a white powdery residue collecting on the heater and pump, descale!
• The insulation of the box is not great. I have measured that, when the box stands on a couple of cork trivets, it consumes around 150-180W to maintain the temperature at 60 degrees. This could be improved by insulating the box better. One option might be to put the whole thing in a soft picnic cooler bag or similar.

For the record, I hate the word beverage.

English speakers: nevermind. Anyway, I, too, saw this yesterday. Didn’t have my camera along though.

So, a few people have been contacting their local friendly chiropractors regarding the recent ASA ruling. I think Martin was the first; jdc325 and Tristan have also done their bit, the latter with remarkable success!

The ASA ruling states that the chiropractor could not “refer to the treatment of IBS, colic and learning difficulties” in his advertising. Now, it should be noted that the ASA do not regulate advertising on websites (but, randomly, they do on leaflets!) However, the General Chiropractic Council’s own Code of Practice states that chiropractors may “publicise their practices or permit another person to do so consistent with the law and the guidance issued by the Advertising Standards Authority.” My interpretation of the GCC guidelines is that they extend the ASA’s recommendations from advertising to all information published by GCC members.

Please note: I have no reason to believe Oxford Chiropractic Clinic are being deliberately dishonest or are trying to mislead the public. I also do not believe their claims are significantly different from any other chiropractor, or even the General Chiropractic Council. They happened to be local to me, so I contacted them. I am sure they are perfectly capable chiropractors, highly trained in their vocation, and their ability and willingness to twist your spine is up there with the best of them. My only motivation in contacting them was trying to ensure that any efficacy claims presented on chiropractors’ websites are substantiated and backed up by evidence.

On Monday 25 May I sent the following to the Oxford Chiropractic Clinic:

I am writing to request that you remove misleading claims from your website at http://oxfordchiroclinic.com/. I wanted to give you an opportunity to respond before contacting the General Chiropractic Council.

On page http://oxfordchiroclinic.com/wellness_topics/14_Colic.html you suggest that chiropractic may help with colic.

On 20 May the Advertising Standards Authority ruled in the case of Dr. Carl Irwin that the chiropractor could not continue to refer to the treatment of colic. The ruling is available here: http://www.asa.org.uk/asa/adjudications/Public/TF_ADJ_46281.htm

According to the General Chiropractic Council’s Code of Practice, available at http://www.gcc-uk.org/files/link_file/COPSOP_Dec05_WEB(with_glossary)07Jan09.pdf, chiropractors “may publicise their practices or permit another person to do so consistent with the law and the guidance issued by the Advertising Standards Authority.”

The ASA ruling is incompatible with the claims currently displayed on your website, and therefore would appear to place you in breach of GCC guidelines.

Please let me know when you have remedied the situation, or explain why you think this ruling does not apply to you.

Today my patience was rewarded with the following message:

Thank you for your interest in our website. In common with other regulated health professionals (including chartered physiotherapists) who utilise a similar technique to ours, we have found that babies with colic respond well to chiropractic care. At Oxford Chiropractic Clinic we have been successfully treating children for 27 years and our website explains the range of options available to parents of infants suffering from colic, itself an ill-defined condition with no clear aetiology.

Your e-mail contains the threat that you will contact the General Chiropractic Council if I do not remove certain materials from the Oxford Chiropractic Clinic website. You also refer to the ASA guidelines and ask why I think the ruling does not apply to me.

I understand that you are a research scientist. If this is correct, I am sure that you will understand the importance of having properly researched your information before seeking to threaten individuals. Had you bothered to go to the ASA website (http://www.asa.org.uk/asa/about/Guided%20Tours/New%20Media/) you would have seen that the ASA Code does not cover claims made by companies on their own websites.

It is a shame when those who are ill-informed seek to disrupt the legitimate business activities of others; still worse when they make threats based on false information. I would suggest that before sending such emails in the future you might reflect on your motives and question the wisdom of your actions.

I actually think it’s mighty nice of them to reply, and I thank Oxford Chiropractic Clinic for taking the time. However, a few things strike me as strange.

1. Thrice they mention that I have sent them a “threat”. I am “threatening” to contact the GCC. I don’t understand why the Oxford Chiropractic Clinic considers it threatening if I contact a regulatory body to ensure its member is compliant.
2. The paragraph “I understand that you are a research scientist…” seems to be taken nearly verbatim from Russell Dean’s reply to Martin, except for that reference to my “threats”, and the pieced-together reminder of the “importance of having properly researched your information before seeking to threaten individuals.” (That’s the first lecture in Research Science 101: first research information, then seek to threaten individuals.)
3. The last sentence in particular seems somehow menacing. Maybe as a non-native English speaker I’m just misinterpreting it, but are they suggesting that making sure healthcare practictioners comply with the appropriate regulation is unwise?

So, erm, that’s what I told them in a reply.

Thank you for your email.

Had you bothered to go to the ASA website (http://www.asa.org.uk/asa/about/Guided%20Tours/New%20Media/) you would have seen that the ASA Code does not cover claims made by companies on their own websites.

I had indeed.

As I pointed out in my email, the GCC permits its members to “publicise their practices [...] consistent with the law and the guidance issued by the Advertising Standards Authority.” My interpretation of the wording is that, even though websites are outside of the ASA’s jurisdiction, the GCC clause extends the ASA guidance to any publication. In other words, a website that promotes chiropractic for the treatment of colic is not “consistent with the guidance issues by the ASA” as defined by the GCC. As I said earlier, I wanted to get your interpretation of the rule before approaching the GCC for clarification.

It is a shame when those who are ill-informed seek to disrupt the legitimate business activities of others; still worse when they make threats based on false information.

It is certainly not my intention to disrupt legitimate business. I do believe there is a certain amount of evidence that chiropractic treatment may be useful for certain musculoskeletal conditions. However, I don’t believe there is credible evidence to support the claim that that chiropractic is effective for colic. If you are able to provide such evidence, I’ll be happy to retract any objections I have to your website content.

Also, I am not entirely sure what ‘threat’ you refer to. Do you consider it threatening if I contact a regulatory body to ensure its member is compliant?

I would suggest that before sending such emails in the future you might reflect on your motives and question the wisdom of your actions.

I hope you agree that the regulation of healthcare, alternative or not, is very important for the safety of the public. Do you feel that making sure healthcare practictioners comply with such regulation is “unwise”?

I guess next up is contacting the GCC for clarification. Unless of course I find in my inbox a peer-reviewed, methologically sound study that proves that chiropractic can treat colic. Then I’m happy to apologise and admit defeat.

This is how I did it under Ubuntu:

1. Download xpvox here.
2. Compile it (I had to install libforms and then change all instances of #include "forms.h" to #include <X11/forms.h>).
3. Install speex.
4. Make sure /dev/dsp0 exists (if not, mknod /dev/dsp0 c 14 3).
5. Run xpvox -ios | speexenc -V --rate 44100 - out.spx.

After you quit xpvox, you’ll find a file called out.spx which contains all recorded traffic, with silent bits cut out.

This is what BA thinks Europe looks like:

Cropped around Finland:

Google Earth’s view on the same area:

The map is proudly produced by Oxford Cartographers.

20080125-102856.flv