Reading codes with a phone camera: practical tips

A phone camera is not a dedicated scanner, but used properly it delivers enough accuracy and speed for most warehouses. The difference lies in small things: lighting, distance, the state of the label and the worker's habits. Those small things make the difference between a smooth count and a frustrating one. Below are some practical tips.

Lighting decides

The camera recognises a code by the sharpness of its black and white bars. When there is too little light, contrast drops and reading slows.

• The inside of a rack is often in shadow. Switch on the phone's torch or turn the code toward a lit aisle.
• Glossy cellophane and thermal film reflect lamp light, and the code vanishes into a white glare. Tilt the phone slightly so the reflection moves aside.
• Strong sunlight is a problem too, because the screen is hard to see. Stand on the shaded side or raise the screen brightness.

Do not leave screen brightness permanently at maximum, or the battery will go quickly. Work at a medium level and raise it where needed.

Distance and angle

The commonest mistake is bringing the phone too close to the code. The camera needs distance to focus. For a small barcode 10 to 15 centimetres usually works well, and for a larger label 20 to 25. If the code looks blurred on screen, slowly pull the phone back instead of moving closer.

Angle matters as well. Hold the phone nearly parallel to the code: at a steep tilt the bars are squeezed together. On a cylindrical container (a bottle or a jar) the code is curved, so aim at the centre of the code and hold the container flat so it does not roll.

Long labels are a special case. If the code does not fit in the frame completely it will not read, so move the phone back a little and bring both ends of the code into view. Conversely, a very small code needs a closer approach, but only until focus is lost.

The state of the label

Most problems lie not in the camera but in the label:

1. A creased or torn code. A code with broken bars will not read. Put a new internal label on that item.
2. Faded thermal print. Over time the paper darkens or the writing wears off. Such labels disappear quickly in the light.
3. Moisture. Goods brought out of a cold room gather condensation. Wipe the label with a dry cloth and read it afterwards.
4. Several codes on one box. The unit code, the pack code, the outer carton code: agree beforehand which one counts.

Habits of hand and phone

Another cause of slow work is a worker hunting for the code while the screen shakes. Two simple habits reduce the problem. The first is to press the elbow against the body, so the hand shakes less. The second is to know where the code usually sits: it is often in the same corner of the box, so the worker looks in the same place every time.

Wipe the camera glass now and then with a soft cloth. Dust and fingerprints build up quickly in a warehouse, and a clean lens noticeably speeds up reading. If you work in gloves, choose thin ones that are touchscreen compatible.

The app's sound or vibration confirms that the code has been read. In a noisy warehouse the sound cannot be heard, so switch on vibration: the worker moves on to the next item as soon as the signal arrives, without staring at the screen. It saves a second or two on each position, which adds up to real time over a day.

If the code will not read

Sometimes a code will not read at all. Then do not waste time:

• Type the digits printed under the code by hand. Most apps check the final (check) digit and will flag a typing error at once.
• Find the item by name or article number.
• If it happens often, put the item on a separate list and apply an internal label later.

Conclusion

Camera reading speed rests on three things: good light, the right distance and a healthy label. The rest is habit: elbow in, lens clean, no time spent on an unreadable code. A small test before the count saves a lot of time on the big day. If you need dedicated scanning equipment and an experienced crew, order a count from StockCheck: the team arrives with scanners and hands over the result as a finished report.