Silicon ChipAmScope Stereo Microscope - July 2014 SILICON CHIP
  1. Outer Front Cover
  2. Contents
  3. Publisher's Letter: Argo drones gathering deep sea data
  4. Feature: Argo: Drones Of The Deep Oceans by Dr. David Maddison
  5. Review: AmScope Stereo Microscope by Andrew Levido
  6. Project: Threshold Voltage Switch by John Clarke
  7. Feature: Eye-Fi Mobi SD Wireless Camera Cards by Ross Tester
  8. Subscriptions
  9. Product Showcase
  10. Salvage It! Wrecking The Computer Itself by Bruce Pierson
  11. Project: Micromite, Pt.3: Build An ASCII Video Display Terminal by Geoff Graham
  12. Project: Touch-Screen Digital Audio Recorder, Pt.2 by Andrew Levido
  13. Project: L-o-o-o-n-g Gating Times For The 12-Digit Counter by Jim Rowe
  14. Order Form
  15. Vintage Radio: The upmarket 1950 HMV R53A radiogram by Rodney Champness
  16. Market Centre
  17. Notes & Errata
  18. Advertising Index
  19. Outer Back Cover

This is only a preview of the July 2014 issue of Silicon Chip.

You can view 38 of the 104 pages in the full issue, including the advertisments.

For full access, purchase the issue for $10.00 or subscribe for access to the latest issues.

Items relevant to "Threshold Voltage Switch":
  • Threshold Voltage Switch PCB [99106141] (AUD $10.00)
  • Threshold Voltage Switch PCB pattern (PDF download) [99106141] (Free)
Items relevant to "Micromite, Pt.3: Build An ASCII Video Display Terminal":
  • PIC32MX170F256B-50I/SP programmed for the Micromite Mk2 plus capacitor (Programmed Microcontroller, AUD $15.00)
  • PIC32MX170F256D-50I/PT programmed for the Micromite Mk2 (44-pin) (Programmed Microcontroller, AUD $15.00)
  • CP2102-based USB/TTL serial converter with 5-pin header and 30cm jumper cable (Component, AUD $5.00)
  • Firmware (HEX) file and user manual for the Micromite (Software, Free)
  • Firmware (HEX) file and user manual for the 44-pin Micromite (Software, Free)
  • 44-pin Micromite PCB pattern (PDF download) [24108141] (Free)
  • 44-pin Micromite PCB [24108141] (AUD $5.00)
  • ASCII Video Terminal PCB [24107141] (AUD $5.00)
  • PIC32MX270F256B-I/SP programmed for the ASCII Video Terminal [2410714A.HEX] (Programmed Microcontroller, AUD $15.00)
  • MCP1700 3.3V LDO (TO-92) (Component, AUD $2.00)
  • Firmware (HEX) file for the ASCII Video Terminal [2410714B] (Software, Free)
  • ASCII Video Terminal PCB pattern (PDF download) [24107141] (Free)
Articles in this series:
  • The Micromite: An Easily Programmed Microcontroller, Pt.1 (May 2014)
  • The Micromite: An Easily Programmed Microcontroller, Pt.2 (June 2014)
  • Micromite, Pt.3: Build An ASCII Video Display Terminal (July 2014)
  • The 44-pin Micromite Module (August 2014)
Items relevant to "Touch-Screen Digital Audio Recorder, Pt.2":
  • Touch-screen Audio Recorder PCB [01105141] (AUD $12.50)
  • PIC32MX695F512H-80I/PT programmed for the Touchscreen Digital Audio Recorder (Programmed Microcontroller, AUD $30.00)
  • Firmware for the Touchscreen Audio Recorder [0110514B.HEX] (Software, Free)
  • Touch-screen Audio Recorder PCB pattern (PDF download) [01105141] (Free)
  • Touch-screen Audio Recorder end panel artwork (PDF download) (Free)
Articles in this series:
  • Touch-Screen Digital Audio Recorder, Pt.1 (June 2014)
  • Touch-Screen Digital Audio Recorder, Pt.2 (July 2014)
Items relevant to "L-o-o-o-n-g Gating Times For The 12-Digit Counter":
  • 2.5GHz 12-Digit Frequency Counter Main PCB [04111121] (AUD $20.00)
  • 2.5GHz 12-Digit Frequency Counter Display PCB [04111122] (AUD $12.50)
  • 2.5GHz 12-Digit Frequency Counter Add-on PCB [04106141a/b] (AUD $12.50)
  • PIC16F877A-I/P programmed for the 2.5GHz 12-Digit Frequency Counter [0411112C.HEX] (Programmed Microcontroller, AUD $20.00)
  • VK2828U7G5LF TTL GPS/GLONASS/GALILEO module with antenna and cable (Component, AUD $25.00)
  • 2.5GHz 12-Digit Frequency Counter front panel [04111123] (PCB, AUD $25.00)
  • Firmware for the 2.5GHz 12-Digit Frequency Counter project [0411112C.HEX] (Software, Free)
  • 2.5GHz 12-Digit Frequency Counter Main PCB pattern (PDF download) [04111121] (Free)
  • 2.5GHz 12-Digit Frequency Counter Display PCB pattern (PDF download) [04111122] (Free)
  • Long Gating Time Add-on Module for the 2.5GHz 12-Digit Frequency Counter PCB pattern (PDF download) [04106141a/b] (Free)
  • 2.5GHz 12-Digit Frequency Counter front and rear panel artwork (PDF download) [04111123] (Free)
Articles in this series:
  • A 2.5GHz 12-digit Frequency Counter, Pt.1 (December 2012)
  • A 2.5GHz 12-Digit Frequency Counter, Pt.2 (January 2013)
  • L-o-o-o-n-g Gating Times For The 12-Digit Counter (July 2014)

Purchase a printed copy of this issue for $10.00.

AmScope Stereo Microscope a boon for working with surface-mount devices How you do cope with assembling PCBs with surface-mount devices? You can always inspect the solder joints with a magnifying glass after they have been made. Or perhaps you use a large illuminated magnifying glass while you solder. But the “deluxe” way is to use a stereo microscope. T hese days it is more or less impossible to avoid surface-mount technology if you are involved in building or repairing electronics. Almost all the really interesting devices seem to be available only in finepitch or leadless packages. Rather than fight this trend, I have been working quite happily with SMT technology 22  Silicon Chip for many years and have developed an armoury of tools and techniques to cope with most of the packages those devious chip designers can dream up. One of these tools was a very cheap, hand-held USB microscope. Review by Andrew Levido This was handy for inspecting joints or looking for solder bridges but it was not practical to use while soldering since the working distance (the distance between the work piece and the lens) was only around 20mm and there was a considerable lag in the video. Thus, I tended to do most of my SMT work without magnification. siliconchip.com.au Viewing your work through the eyepieces then moving your soldering tool to the same place takes a bit of getting used to – but after a couple of hours, it does become second nature. The microscope is perfect for surface-mount devices. Recently, after spending an afternoon hunched over the bench with my face only centimetres from a PCB, the crick in my neck told me something had to be done. I hit the ’net to see what the options were. I steered away from video microscopes because I was wary of the video lag effect. I therefore narrowed my search down to optical stereo microscopes with a wide field of view and a good working distance. Incidentally, I should point out the difference between a compound microscope (the type you might have used in science at school) and a stereo microscope. A compound microscope may have one or two eyepieces but has a single objective lens close to the object being examined. Often there are several objective lenses mounted on a turret but only one is in the optical path any time. Compound microscopes offer high magnifications (up to 1600x) but the image is two-dimensional. A stereo microscope, on the other hand, has two completely separate siliconchip.com.au optical paths offering slightly different views, resulting in a three dimensional image. Magnification is usually lower than for compound microscopes (less than 100x). What’s available? There is a wide variety of options out there, ranging from the top-ofthe-line Mantis Elite at nearly $3,000 to low cost “toy” microscopes under $100. After much searching I settled for a microscope from the US-based online retailer AmScope (www.amscope. com). They offer a truly bewildering array of microscope types and configurations. Ultimately I chose their SM4TX-144A microscope package. See www.amscope.com/sm-4tx-144a.html This is a trinocular microscope: as well as two eyepieces, it has a third optical port suitable for mounting a camera. It has a magnification ranging from 3.5x to 45x, continuously variable via a zoom knob, a wide field of view at 65mm and a working distance of 200mm. It comes with a boom stand that allows the microscope to be moved in and out of the workspace and a LED ring light to illuminate the work surface. At about $US550 this seemed to be a very reasonable package. I went onto the website and placed my order, only to discover the shipping would be around $US360, bringing the total to almost $1000 Aussie dollars – right at the top end of what I was prepared to spend. Given that the package weighs over 30kg, there were no cheaper shipping options. I swallowed hard, entered my credit card details, hit the go button and sat back to wait. But a few days later I got an email from AmScope explaining that they did not accept foreign credit cards, asking me to pay via their PayPal account. No problem here but it seems an inefficient way to operate. They also stated: “all of our items come standard 110V, if you need 220V please let us know as there is a $5 fee for the upgrade”. Again, no big issue – but the website could be a bit more friendly to overseas purchasers. A few weeks later two parcels duly arrived, one containing the microscope head, the eye pieces, Barlow lens, eye guards, a plastic dust cover, the ring light and its control box. The second box (which I could barely lift) contained the parts for the boom stand. This is truly a massive (30kg) piece of hardware. Caveat emptor! By the way, there is an enormous price range for the AmScope SM-4TX144A on the internet – and we’re not sure why. Some sources offer this microscope for about the same net price as AmScope or even less: after ordering (of The eyepieces have a rubber shroud which can be extended, as shown here, or collapsed for those of us who are visually aided (ie, wear glasses!). July 2014  23 The ring light control box is also a bit disappointing and has a bit of a home-made feel. It works fine but the buttons feel cheap and the ring light connector is a USB mini B type. I don’t like the idea of using these connectors for non-USB purposes in commercial gear. One day some “valued customer” will plug a USB device into the control box or the ring light into a USB device with ugly consequences. The control box does have a CE mark label (although no US or Australian approval marks), so I assume it is reasonably well designed and made. Using It Included in the package is this ring LED worklight, absolutely essential for illuminating the subject, along with its power supply/controller. We have just a few reservations about the quality – but it works! course!) we found one site selling for $US520 with $US53 shipping to Australia (~$AU600). But there are others selling for much more (eg, >$AU1350 inc shipping) with no apparent “extras”. You can order this scope through amazon.com (“sold and shipped by AmScope”) which suggests a $US499.98 ($AU537) including postage. But when you go through the cart process to order one, you’re likely to find that they either “will not supply to your geographic area” or the “free postage” suddenly becomes not quiteso-free. That same site adds a “per shipment” charge of $US29.00 and a “per weight” charge of $US8.99 per pound – and the AmScope website states a shipping weight of 68 pounds. So that free postage could equate to $US611 or more than $AU650! So if you order on line, shop around, check the fine print and watch for any emails from the supplier. In the end, I was happy that I ordered it from AmScope direct (and the security that provides) even if I did pay a premium. Assembly . . . instructions? The assembly instructions are pretty rudimentary and I found it easier to use a photograph from the website rather than the provided booklet to assemble the stand. Otherwise, assembling the microscope head is fairly foolproof with 24  Silicon Chip the two eyepieces dropping in place and the Barlow lens screwing onto the objective lens at the bottom. The ring light is attached by three radial thumbscrews to a supplied collar that is screwed on to the Barlow lens. Incidentally, the Barlow lens is used to increase the working distance at the expense of magnification. In the case of my microscope, the Barlow lens doubles the working distance and halves the magnification. If it is removed, the maximum magnification increase to 90x but the working distance is only 100mm. The ring light is worthy of comment as it contains no less than 144 LEDs arranged in concentric rings. The controller allows the LEDs to be dimmed and also for separate control of each quadrant. This is handy if you want to light from one side only (for example to read those pesky black-on-black IC markings). The ring light and its control box are shown above. Note the (mis)use of a USB connector and the US mains cable. The photo opposite shows two of the four segments illuminated. One surprise was that my five-dollar “220V upgrade” consisted of an unapproved Chinese power adaptor so I could plug the supplied US-style 2-pin mains plug into an Aussie socket. Pretty dumb really, since the mains cable connects to the light control box via a shaver-style cord. It would have been better (and safer) if they had simply packed an Australian cable. Apart from a bit of playing about, the first intensive use of the microscope was to construct the prototypes for the Audio Recorder published in the May and June 2014 issues of SILICON CHIP. This required five or six hours of intensive SMT work including soldering 0.5mm pitch TQFP microcontrollers and a 3mm x 3mm leadless pack, also with 0.5mm pitch. Although it took a few minutes to get used to the idea of looking more or less straight ahead, while my hands were working down at bench level, I quickly became a complete convert to working with a microscope. For most work, I kept the magnification quite modest, with the greatest benefit being improved posture and zero eyestrain. I think the consistency of my solder joints was also improved. The microscope really came into its own when checking for solder bridges between pins or to check that a pin had properly reflowed. By increasing the magnification, those tiny 0.25mm gaps between pins became yawning chasms and any soldering faults were rendered blindingly obvious. I was even able to tilt the microscope 45º to look at the edges of the leadless packages to see if the solder had reflowed properly. As mentioned above, the ring light has plenty of modes but in practice I used it with all segments on and at close to full brightness almost all the time. The ring light is essential since without it the microscope image is almost unusable, despite my having a very bright lab. I found the working distance to be completely adequate and never felt constrained by the presence of the microscope while using the soldering siliconchip.com.au Helping to put you in Control N480D PID Controller Low-cost PID controller that accepts T/C & RTD input, 3 relay outputs & 1 pulse output for driving SSRs. Auto-tuning PID function, dual display & ramps soak function. 240 VAC powered. SKU: CET-052 Price:$79+GST Wireless Freezer Thermometer FT0076 is an 8 channel wireless thermometer suitable for monitoring temperature of freezers. It has temp accuracy of ± 1 °C. Comes with 2 remotes & up to 8 sensors can be added, plus alarm configuration. 100 m transmission range. Batteries not included. SKU: UTS-005 Price:$85+GST Here’s that same LED ringlight in action. It simply clips to the bottom of the Barlow lens (also supplied) and can be varied in brightness as well as in the segments illuminated. We tend to use it with all four on and flat out! iron or any of my usual tools. The field of view was also fine but there was an unusual side effect of viewing the work through what is effectively a 65mm diameter hole. I would tend not to lift my eyes from the eyepieces to grab the soldering iron, for example, and then fail to be able to bring it to the “hole”. The answer of course, is to only look through the microscope once your tools are nearly in position, but this took a little practice. One other pleasing feature compared to the old USB microscope I used to use was the true three-dimensional nature of the image. You can really see the way the solder fillet runs up the end of a SMT capacitor, for example. The depth of field is adequate at about 5 or 6mm for typical levels of magnification. Once you start using the microscope, you really begin to appreciate that heavy stand that cost so much to ship. The horizontal movement is very smooth and the solid construction and heavy counterweights mean that the microscope remains rock solid even at the fullest extension. This means you can push the microscope right out of the way when you don’t need it, but pull it into place in a couple of seconds. I wear spectacles all the time and I was a little concerned how these would work with the eyepieces since I have had trouble with microscopes and telescopes before. I need not siliconchip.com.au have worried, since the rubber eye guards (in their folded-down position) worked perfectly with my glasses. These eye guards also fold up for those lucky enough to have perfect vision. Conclusion On balance, the AmScope SM-4TX144A is a great tool for anyone regularly using surface mount components – and that’s most of us these days. It is easy to use and will in all probability significantly improve the quality of the work you can do, and give you the ability to tackle the very fine pitch, leadless, and miniscule components that seem to be the norm these days. I think that the manufacturer could easily do a little more to make things easier for non-US purchasers, by improving the website, fixing the “220V upgrade” and most importantly optimising the freight. If I have a criticism it is the poor documentation and the barely adequate quality of the ring light power supply. At around $1000 delivered, it is an investment on par with an entry-level oscilloscope or a top quality soldering station, so not one to be made lightly. Nevertheless, I am a complete convert, and would recommend a stereo microscope if you are doing a lot of SMT work. For further information, go to the Amscope website at www.amscope. com SC Limit Switch Roller adjustable lever type limit switch comes in a solid IP67 die cast cast with LED operation indicator. It is designed to for high mechanical intensity environments where it is exposed to heat, oil & dust. 24 VDC powered. SKU: HNR-402 Price:$49.95+GST Warning Red Light Simple round cap, wall mount warning red light with PIR sensor that turns on light when motion is detected. It features 4 selectable melody tones that are rated to 90 dB. 24 VDC/AC powered. SKU: HNL-101 Price:$89.50+GST 4 Channel Temp Logger Serial port powered, temp data is output as a continuous data stream over an RS-232 serial port. Supports up to 4 x DS18S20 sensor, only 1 is included. PC software is provided for logging data to a CSV file. SKU: KTA-145 Price:$25+GST Ethernet Serial Server Connects an RS-232, RS422 or RS-485 serial signal to an ethernet network. 10/100 Mbps ethernet supported. SE5001 offers fullduplex and bi-directional data that is transmission transparent between the serial port and the Ethernet network. DE-9 serial port. 5 to 30 VDC powered. SKU: ATO-101 Price:$129+GST GSM Wireless Home Alarm Kit Home or office wireless alarm kit with base unit, wireless PIR and door sensor, strobe siren, 12 VDC plugpack and two keyfob remotes. GSM functions allow notifications to be sent to your mobile phone. SKU: KPR-100 Price:$249+GST For OEM/Wholesale prices Contact Ocean Controls Ph: (03) 9782 5882 oceancontrols.com.au July 2014  25