How I modified a cheap greetings card sound module to provide sound for a small diesel loco

When I had finished constructing my IP Engineering plate frame Simplex loco (see How I constructed an IP Engineering plate frame Simplex) and equipped it with Deltang radio control, I decided she ought to have a simple sound system. Owing to its diminutive size, the MyLocoSound card and even the Mtronics soundcards were going to be too large; I needed something ultra small and, being a skinflint, something ultra cheap.

On a whim, I sent for a very cheap sound module (£1.29 inc postage) which was intended to be used for musical greetings cards. This came equipped with a 'play' button, a 'record' button, an LED, a microphone and a speaker in addition to the board itself and a couple of small batteries.

The first job was to track down a suitable sound effect. Fortunately, I had shot some video of Simplexes (Simplices??), at the Apedale Valley Light Railway, and so was able to record the sound of one ticking over by placing the mike near the speaker on my laptop and holding down the record button until the LED flashed to show it had reached its full 10 second limit.

I needed to do the recording a couple of times until I was happy with the result. Not exactly high fidelity, but the sound is just about recognisable.

After removing the blobs of hot glue from the board to get at the connections, ......

..... by prising them off with a finger nail, ......

.... the next job was to find a way of making the recording loop continuously. Some research on the internet revealed this was possible and so I experimented by touching the end of a lead soldered to the Play button connection on the board to various contacts on the board until I found the right spot. This turned out, for some reason, to be the terminals for the microphone. Once I'd satisfied myself that this worked, a lead was soldered permanently from the play button connection on the board to one of the mike terminals.

There is a pause of roughly 0.5 seconds at the end of each 10 second cycle. I've not yet found a way of overcoming this. I could try synching two boards to work in unision but slightly out of step, or find a sound effect which has a distinct engine beat and try to coincide the pause with the rhythm of the engine. However, for now, I am prepared to live with this slight anomaly.

Once, I was satisfied with the sound, I unsoldered the leads for the mike, the LED and record button, leaving the leads for the Play Button and the speaker still connected.

I then turned the board over and unbent the tags holding the batteries to the board.

I then carefully unsoldered the metal cradles for the batteries.

Ith a craft knife, I carefully scored across the board to separate the section of the circuit board holding the batteries from the rest of the board and snapped it off.

Two wires were then soldered to the tracks on the circuit board leading from the batteries.

As the Simplex was powered with a single 3.7 volt li-ion battery, I checked that this would be a sufficient for the board. The leads were connected to the negative supply from the loco battery and to the output side of the power switch. This supply proved sufficient to power the board (confirmed by pressing the 'Play' button.

When I install boards in my 12v powered locos, I will need to use a voltage regulator circuit such as this to limit the supply voltage for the board (see below).

I decided to replace the loudspeaker supplied with the module for one slightly smaller in diameter to enable it to be fitted under the cab roof. A small speaker was purchased from Maplin (Part code N93FU ). The 'Play' button was also positioned under the cab roof, so the loco could be run with or without sound.

 The circuit board fitted quite neatly under the engine cover of the Simplex, being held in place with a blob of Blutak.

As indicated above, for now I am happy to live with the hiccup in the sound, though may experiment with ways of overcoming it.

I have also added another sound module to the Simplex containing a klaxon sound. As the sound does not need to loop, there was no need to solder the lead from the play button connection to the mike connection. The klaxon sound board is triggered by the output from the C output pad on my Deltang Rx65b receiver/controller, responding when the bind button is pressed on my Deltang Tx22 transmitter.

As you can see from the video. The klaxon sound is quite clear when the engine sound is not running, but is somewhat muffled by the engine sound. This is probably because both boards are connected to the same speaker. I will try experimenting with adding low value resistors into the circuit between the boards and the speaker to see if I can balance the outputs. If I had more space, the klaxon board would have its own speaker.

As indicated above. I am intending to install a couple of these boards into another of my small diesel locos which is powered by a higher voltage battery pack. I will need to use a voltage regulator circuit to reduce the voltage for the sound board, but there might be space in the second diesel for two loudspeakers.

I might also experiment with ways of overcoming the half second hiccup at the end of the looped recording .

To be continued ........

Progress Report 61

It has been quite an eventful summer - not least because the weather has been very changeable which is not good news for garden railway modelling. However, there have been a few developments since the last Progress Report (see Progress Report 60).

• In terms of infrastructure, the major development has been the completion  (after two years) of the viaduct crossing the access to the patio. In addition, the unintended incline at the end of the swing bridge on the approach to Bulkeley station has been iron-out.
• Very little has happened with the permanent way, though the siding for the cattle dock at Beeston Market has been extended a little.
• A very pleasing development has occurred in the motive power department - the last remaining track-powered locomotive (Fowler No.7 - Tollemache) has been converted to battery power
• There have been several developments in Controls - some of the Deltang receiver/controllers have been updated in the locos and a new Tx20 Deltang transmitter has been constructed to now give three separate controllers for locomotives
• Some of the little-used rolling stock has been passed on to other railway companies and there have been a number of general repairs to serving rolling stock
• Operating sessions have been sporadic - partly owing to the unpredictable weather, partly because we have been away on holiday and partly because other developments have taken priority. However, I have managed a couple of full operating sessions and played host to fellow modeller.

Infrastructure

Two years ago, I decided to replace the rather ramshackle structure which pretended to be a viaduct across the access path to the patio. This had become an experimental test-bed for construction techniques with the plywood base being covered at various times with a range of claddings such as tile cement, plaster of Paris, grout and filler. The intention was to indent and/or scribe these materials to represent stone blockwork. None had proved particularly successful and the plywood was beginning to rot.

 As the viaduct needed to be readily removable to allow access, I wanted something relatively lightweight but nonetheless reasonably realistic. I had already built structures using balsa wood to represent stonework (following ideas proposed by Peter and Kes Jones in Making Model Buildings for Garden Railways). And so a lightweight plywood substructure was made and clad in around 3500 individually cut, shaped, glued, grouted, textured and painted balsa wood blocks.

 

On a less ambitious scale, there had always been a slight drop at the end of the swing bridge at Bulkeley but I had begun to notice that the slope was becoming more severe. The trackbed at Bulkeley seemed to have dropped by around 5cm.

Previously, I had attacked the slot into which the end of the bridge fitted with a hammer and cold chisel, but this time I felt the time had come for more drastic action. The slot was deepened with an angle grinder.

The transition from bridge to terra firma is now a lot less abrupt - but as you can see, the ground level has shifted quite considerably over the past ten years.

Permanent Way

Apart from the usual ongoing maintenance of keeping the stock moving and the wheels on the track, there have been no major developments on the permanent way since the last progress report. The most significant development has then the extension of the siding serving the cattle dock at Beeston Market. When I built the cattle dock (see How I constructed a cattle dock), I was more concerned with ensuring that the dimensions of the gates and railings matched the positions of the doors on the four cattle wagons which the line possessed at that time.

What I hadn't appreciated was that the overall length of the siding would not accommodate the fifth ( Accucraft Welshpool & Llanfair) cattle wagon which the line acquired. Fortunately, there was sufficient space between the end of the siding and the adjacent tracks for it to be extended by 3cm. However, the track had been embedded in concrete and so I was unsure as to whether it would be possible to extend the siding without major engineering works. I decided that, if I could sever the track just before the rail built buffer stop, I might be able to insert a short length of track with the minimum of disruption.

The track was cut with a slitting disk attached to a mini drill and the buffer stop was prised out with a hammer and chisel. The 3cm length of track was inserted into the gap.

The siding is now just the right length to accommodate all five cattle trucks, with plenty of room for stock to pass by.

Motive Power

The biggest development here has been the conversion of my last track powered locomotive to battery power. The Fowler(ish) Loco No. 7, Tollemache, was the first loco I scratchbuilt and so has particular poignancy for me (see How I constructed an early Fowler diesel locomotive).

During the build, I had had a major problem with the layshaft. The only flycranks I could find (from Garden Railway Specialists - GRS), had 8mm offsets but the cranks on Tollemache's drivers had 10mm offsets. Although I solved the problem at the time by slotting the bearings in the connecting rods, I was never happy with the sloppy motion which this produced. I felt I needed to find a better way of solving the problem before I set about making the conversion to battery power. It turned out that the solution was a lot more straightforward than I had anticipated (see How I increased the offset on my GRS whitemetal flycranks)

Once this problem had been sorted out, the installation of the three 18650 li-ion batteries, protection board, switch, charge socket and the Deltang Rx65a receiver/controller was very straightforward (see How I converted my Fowler diesel to battery radio control).

She has now assumed duties and has already participated in a couple of test runs. I can't wait for some decent weather so she can once more take part in a full operating session. As you can see, I am now more than happy to video her running slowly.

Controls

There have been a few developments in the area of control technology on the railway. The most significant is the construction of a new Deltang transmitter, a Tx20 (see How I constructed a Deltang Tx20 transmitter).

As indicated above, Fowler Loco No, 7 (Tollemache) has now been converted from track power to battery power using the Deltang Rx60a receiver which was removed from Manning Wardle Loco No. 6 (Harthill).

I had re-bound this loco from my Tx22 transmitter to my Tx21 transmitter but was finding that the Tx22-enabled Rx65a was struggling to remain bound to the Tx21. Rather than re-program the Rx60a, I decided to buy another Rx65b which was already programmed for use with Tx21 (or Tx20) - an Rx65-2. 

When I constructed an IP Engineering 'Jessie' kit which became loco No. 8 (Wynford), the only suitable Deltang receivers which were available could handle only 1.5amps.  

Wynford sometimes drew more amps than this and so was unreliable with the lower power receivers. To solve the problem I installed a Deltang Rx102 receiver linked to a Brian Jones Mac5 ESC. Since the release of the Deltang Rx65, I have been meaning to install one in Wynford but, as she was functioning happily, I felt there was no urgency. An enquiry on the 16mm NGM forum from a fellow modeller, asking which Deltang Rx would be most suitable for an IP Engineering 'Jessie' with a soundcard, prompted me to replace the Rx102/Mac5 arrangement with an Rx65, to ensure my suggestion was appropriate. The Rx65 needed to be re-programmed to allow the DigiSounds soundcard to be controlled from the transmitter and  Wynford is now happily re-energised and back in service (see How I installed an Rx65 in my IP Engineering 'Jessie').

Manning Wardle Loco No. 4 (Bulkeley) has now had her Deltang Rx60 receiver replaced with an Rx65. Although Bulkeley was working satisfactorily, I have decided that I want to standardise the receivers in my locos and the Rx65 includes features which one day I might want to exploit (eg auto-station stop).

Rolling Stock

Because I have recently constructed a new gunpowder van (see How I constructed a gunpowder van), the Swift Sixteen corrugated van which had been pressed into service as an explosives van was now redundant and so was sold to a fellow modeller through eBay.

Similarly, the Accucraft Lynton & Barnstaple van which I had bought a few years ago was now surplus to requirements. The other vans on the line (converted from LGB vans) are larger and hence L&B van looked out of place. It too followed the corrugated van.

Apart from some ongoing maintenance (mainly re-fixing couplings) there have been no further developments with rolling stock since the previous Progress Report.

Operations

I have had the opportunity for a few operating sessions since the last report in July, though these have been less frequent than I would have liked as holidays, the weather and projects (such as the viaduct) have taken up time that might have been used for running trains. However, a couple of full operating sessions have been squeezed in and from time to time I have run a train or two for an hour or so.

Having constructed a second rake of coaches (see How I converted Bachmann Jackson Sharps into Leek & Manifold coaches), I felt it was about time I ran two passenger trains at the same time (assuming it was a busy market day during the summer season). Here we see Sharp Stewart Loco No. 5 (Tarporley) on an Up passenger .........

...... crossing Manning Wardle Loco No 6 (Harthill) at Bulkeley on a Down passenger service.

During another operating session, a few photos were taken of trains in action ....

Barclay Loco No. 2 Beeston about to depart Beeston Market

Freelance diesel, Wynford, passing the engine shed at Beeston Market

No. 2 (Beeston) passing an Up ore train at Bulkeley

Peckett Loco No. 1 on a Down pickup goods passing an Up ore train at Beeston Castle

No. 1 on an Up goods approaching Bulkeley while No. 2 approaches Beeston Castle on a Down passenger

In addition, the railway hosted a visitor, Derek, who brought two locos with him - a Peckett and a Hunslet built from GRS kits

Derek's Peckett leaving Peckforton, crossing the viaduct

Approaching Bulkeley on Gallantry Bank

Peckett and Hunslet (Linda) storming up Gallantry Bank

Double header approaching Bulkeley

Autumn is upon us. As you can see from the above photo, the apple tree is starting to shed its leaves and there is a definite nip in the air. My railway todo list seems as long as ever and so, over the winter season, I hope to clear some items off it, such as:

• installing interiors and lighting in the Leek & Manifold coaches
• installing solar lighting at the stations
• adding more detail to goods wagons
• exploring auto station stop for locos equipped with Rx65b receivers
• constructing a couple of horse drawn wagons
• constructing buildings for the approach to Beeston Market station
• etc etc etc

As I said in one of my first blog posts made in 2006, I doubt my railway will ever be finished.

How I converted my Fowler diesel to battery radio control

My first scratchbuilt loco was a diesel mechanical loco based on a cross between a standard gauge and a 2' gauge Fowler loco (see How I constructed an early Fowler diesel locomotive). I had been unable to find a 3' gauge Fowler and so surmised it would look similar to their standard gauge locos - albeit smaller.

 When I changed from DCC track power to battery powered radio control, I constructed several locos to be purely battery powered and slowly converted my previously track powered locos to battery power. This particular loco had been sitting on the shelf, awaiting conversion to battery power, for around two years. Her duties were being discharged by my IP Engineering Jessie (Loco No. 8, Wynford) and so there was no immediate need for Tollemache's conversion. I kept putting it off as I knew I'd have to sort out the flycranks which had been a problem during construction. Ultimately, the solution of this problem was a lot easier than I expected (see How I increased the offset of some GRS whitemetal flycranks).

With this problem solved, the path was paved for the loco's conversion to battery power.

 The LGB ToyTrain 0-4-0 motor block was separated from the body and taken apart to remove the wheel and track electrical pickups. I have described this process previously (see How I converted my GRS Peckett to battery power).

 To create space in the engine compartment of the loco, I had to remove the lead flashing to accommodate the three tagged 18650 li-ion batteries which were soldered together in series to provide the 11.1 volts power supply.

This battery pack was then connected to a li-ion battery protection board (see circuit diagram below) which had been bought from China via eBay  ......

 A 3S balance charge socket was also soldered into the circuit to allow the charge levels in the individual cells to be measured.

The charge socket and two-way switch were wired-up with connections to the output terminals on the protection board.

 The switch and socket were then installed in holes drilled in the instrument panel of the loco cab.

 The positive input lead to the Deltang Rx65a was then connected to the switch and the negative lead to the supply contact on the protection board. A lead was also soldered to Pad 2 on the receiver board. This is the output for the rear directional light (my locos are all reverse wired for directional lighting because the first locos I wired-up were all accidentally reverse wired). This lead was then connected to the headlamp LED.

 The incandescent bulb in the headlamp was removed and a bright white LED inserted into the socket (this was actually the most difficult and time consuming stage of the conversion). A 470ohm resistor was then wired into the supply lead for the LED before being connected to the output from the board. The other lead from the LED was connected to the negative terminal on the protection board.

The wiring was then tested by turning on the power switch and binding the receiver to the Tx22 transmitter. The circuit boards and batteries were then insulated with insulation tape to avoid accidental short circuits when the components were squeezed into the engine compartment.

After test-fitting the components, I realised there was some available space to re-instal some of the lead flashing. This was trimmed to size and glued to the sides and roof of the engine compartment with clear Bostik adhesive.

To summarise, the circuit diagram for the conversion indicates how the components were connected. The four leads for the balance charge socket were soldered to the four connections for the batteries on the protection board making sure the order of connections to the batteries was preserved (from positive (red lead) to negative (final black lead)).

The loco was reassembled ..........

...... and then given a few test runs.

Although she has quite good hauling power (as can be seen from the video), I would like to install a little more weight as there is some wheel spin on my 1:40 gradients when hauling a full load. It might be possible to install a couple more pieces of lead flashing in the engine compartment but I will probably also find a few nooks and crannies to add a few more pieces of lead.

Overall, I am delighted to have this loco back in service. She has now been fully recharged and seems to be very controllable. For now, I feel I have sufficient locos to run services on my railway - but who knows whether I might see another prototype which seizes my attention??