Saifullah AhadHow I built it
Brojilo: Check Power BillLive on Google PlayBrojilo: is my electricity meter running fast? How to check
Electricity meter running fast? You can check it without opening anything: rule out the usual reasons for a high bill, run a creep test and a load test, and time the meter’s light. Brojilo is my app, live on Google Play, that times the light with a phone camera and turns it into watts.
01
The problem
A higher electricity bill arrives. The person who has to make sense of it has no special meter equipment, and must never open the meter. The bill’s price steps are hard to follow, tariffs change, a slow meter light can look like no use at all, and a rough estimate is easy to mistake for proof.
02
The plan I wrote
Brojilo turns a phone camera into a meter watcher that never touches the meter. You aim it at the small light marked imp/kWh, or at the dark mark on a rotating disc, and place a guide box over it. The app times the gaps between pulses and works out the power as 3,600,000 ÷ (meter constant × seconds between pulses). It uses the middle value of many gaps, never one, and shows a low-to-high range with it. Until it has at least four steady gaps, it says “Building a stable interval” instead of a number.
From there you can run a fixed 10-minute standby test with ordinary things switched off, compare a baseline with one appliance switched on (for an appliance that switches itself on and off, you keep going until you have seen a full off-and-on cycle), check the meter’s start and end digits, typed or photographed, and rebuild a bill line by line from the tariff that covered that billing period: each price step, the demand charge, tax and total, with the rule’s date and its source. Bills can be rebuilt for the household tariffs of six utilities in Bangladesh (BPDB, BREB, DESCO, DPDC, NESCO and WZPDCL). The meter reading works anywhere the meter has a visible light or disc mark.
Records stay on the phone, and a plain-text summary can be shared, for example to take to the electricity office. The name is a Croatian word for a meter.
03
The build
AI coding agents built it from my written specification. My work was the specification, the rules for when a number may be shown, and the review.
04
What broke: Google Play said no, twice
Google Play rejected Brojilo twice under its rule on misleading claims. An app that uses government information must link the official sources and say clearly that it is not a government app. Brojilo already had both, but every source link was dead. The six links in the app went nowhere: most of their www addresses did not open at all, and one government site showed “Site is not available”. A source link from the tariff service gave “not found”.
The links were moved to the official addresses that really open, the tariff regulator BERC was added, the statement was reworded, and the tariff service was corrected and checked live. Google Play now shows the app updated on August 27, 2026, with the statement at the top and the regulator’s link in the list. The lesson I keep: a link that looks right is not proof that it works.
05
What I have checked, and what I have not
Automated tests replay recorded pulse patterns. At 50, 250, 1,000 and 2,000 watts the result was exact; a very fast 5,000-watt pattern came out at 5,023 watts, less than half a percent off. Dim, bright, tilted, flickering and dropped-frame versions stayed exact. On two phones, an Infinix Note 8 and a Galaxy Z Flip4, the signed release build opened all 15 screens with no crash, the camera ran at about 30 frames a second, and both phones rebuilt the same bill: BDT 1,439.55 for 180 kWh with a 2 kW load on DPDC’s tariff.
What I have not done: in testing, the camera has not yet watched a real flashing light, on a meter or anywhere else, so I make no claim about how close Brojilo is on a real meter.
06
Where it stands
“Brojilo: Check Power Bill” is live on Google Play. It is an independent tool, not a service of any government or electricity company. Its results are estimates for personal checking: they do not calibrate a meter, prove a billing error, or replace a test by the electricity company or a qualified electrician. Keep the phone outside the meter box. Never remove a cover or seal, and never touch wiring.
If you can try it on a real meter with an appliance of known power, I would like to hear how close it came. Email me or message me on LinkedIn.
What this shows about how I work
- A link that looks right is not proof: open it.
- An estimate comes with a range, and no number until enough pulses agree.
- Results come with their limits: tested on recorded pulses, not yet on a real meter’s light.
How to check if your electricity meter is running fast
Most high bills are not a faulty meter, so start with the simple checks. These steps come from UK guidance (GOV.UK and the electricity supplier Octopus Energy). None of them needs the meter opened.
- Rule out the usual reasons first. GOV.UK lists three: the price of electricity has gone up, you have used more (for example in cold weather), or this bill is based on a real meter reading after estimated ones. It calls a faulty meter “unusual”.
- Do a creep test. Only if you are happy switching the mains off at the fuse: switch it off, photograph the reading with the time on it, wait 15 minutes, switch back on and photograph the reading again. If it has not moved, the meter is “very likely operating as intended” (Octopus Energy).
- Do a load test. Switch off all non-essential appliances (not your fridge or freezer). Switch appliances on one at a time, a few minutes apart, and compare what the meter records with each one’s power rating. If one reads much higher than expected, that appliance may be faulty or the meter may be fast; test two more. If every appliance reads high, “it’s most likely the meter”.
- Still looks wrong? Contact your electricity company, with your photos and test results.
Whatever you check, never open the meter box, remove a cover or seal, or touch wiring.
How to check if your electricity meter is accurate
GOV.UK says that “there is no simple way you can test whether your meter is accurate” yourself. The checks above can show that something is wrong; only a test arranged by your electricity company can show whether the meter is. In the UK, the supplier investigates and may fit a “check meter” next to yours, and you have the right to ask for an independent test. The test is free, but you may have to pay the supplier for organising it if your meter turns out to be working correctly. Other countries have their own rules, so ask your electricity company what it offers.
How to check appliance power consumption from the meter’s light
Many meters have a small light marked with a number such as 1000 imp/kWh. It flashes once for each fixed amount of energy. Switch the appliance on, time the seconds between two flashes, and work out: watts = 3,600,000 ÷ (the imp/kWh number × the seconds). At 1000 imp/kWh, a flash every 3.6 seconds means 1,000 watts. Time several flashes, not one, and measure once with the appliance off and once with it on: the difference is the appliance. This is the same rule Brojilo uses.
Brojilo, an app that reads the meter’s light, does this timing with a phone camera: it watches the light or the disc mark, uses many pulses, shows a range, and keeps a record you can take to your electricity company.
Sources: GOV.UK, Office for Product Safety and Standards, “Electricity meters: high bills or meter readings”; Octopus Energy, “Meter Accuracy”.
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