![](https://a.pololu-files.com/picture/0J9152.1200.jpg?056dab31e4806bc27fc31b1270b842bb)
All the student engineering interns we had over the summer from out-of-town colleges are headed back to school, so I get to announce the release of products they worked on over the summer. The new QTR sensors we are releasing today include the 15-channel version laid out by seventeen-year-old Chris H.
![](https://a.pololu-files.com/picture/0J9153.600.jpg?f0e14caac0897ff8cf6ebafcd6fa0f61) |
Hadouken! (2018 summer engineering intern Chris couldn’t come up with a clever pun to use for this picture of him posing with a circuit board he designed.) |
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You can see more about our new line of QTR reflectance sensor arrays in the first blog post I wrote about them a few weeks ago. One cool design and manufacturing aspect I did not mention then is that we designed these boards so that they could be populated at various densities. For example, that lets us make an 8-channel version with 8 mm sensor pitch on the same board that also works as a 15-channel array with 4 mm sensor pitch:
![](https://a.pololu-files.com/picture/0J9148.500.jpg?ff043685a3681ac0b44cdf073115c229) |
QTRX-MD-08RC Reflectance Sensor Array. |
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Here are some diagrams showing some of the thought that went into the soon-to-be released 31-channel version, which can also be populated to be an 8 mm pitch, 16-sensor array; a 12 mm pitch, 11-channel array; and a 20 mm pitch, 7-channel array:
![](https://a.pololu-files.com/picture/0J9155.300.jpg?a760229c6f57354e48d2d275f94ed11a) | Diagram of emitters and drivers on a QTR-HD-31x sensor array board with all sensors populated. |
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![](https://a.pololu-files.com/picture/0J9156.300.jpg?8752e67cc2690c517eb287939d69ea4c) | Diagram of emitters and drivers on a QTR-HD-31x sensor array board with 1/2 sensors populated. |
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![](https://a.pololu-files.com/picture/0J9157.300.jpg?79ab95f236af0a913ae56e3f464011ab) | Diagram of emitters and drivers on a QTR-HD-31x sensor array board with 1/3 sensors populated. |
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![](https://a.pololu-files.com/picture/0J9158.300.jpg?b7379eeb5d63a2612d093880e864777e) | Diagram of emitters and drivers on a QTR-HD-31x sensor array board with 1/5 sensors populated. |
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With so many combinations of sensor types and output circuits, we won’t make every one of the possible arrangements a stock product, but the idea is that if you have an application where a particular sensor pitch is ideal for you, we can quickly make some for you without having to lay out new PCBs.
We expect eight channels on an 8 mm pitch to be a popular variant, so those will be stock products. We have also added the corresponding 4-channel version (using the same boards used for the full-density, 7-channel product), so this new product announcement covers twelve new stock sensor arrays:
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![](https://a.pololu-files.com/picture/0J9133.310.jpg?4cb5bdf7777c0533a19adc9757c9adba) | QTRX-HD-15RC Reflectance Sensor Array. |
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![](https://a.pololu-files.com/picture/0J9151.310.jpg?0fbf501d16e6206a1f52b2df71842d85) | QTRX-MD-08RC Reflectance Sensor Array. |
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![](https://a.pololu-files.com/picture/0J9174.147.jpg?f1536fbc2d28bf96ae7bf9d5617239d7) | QTRX-MD-04RC Reflectance Sensor Array. |
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Our introductory promotions are still going strong! Be one of the first 100 customers using coupon code QTRINTRO and snag any of these new sensors at half price! (Limit 3 per item per customer.)
![](https://a.pololu-files.com/picture/0J9152.1200.jpg?056dab31e4806bc27fc31b1270b842bb)